Oracle VirtualBox has a very flexible internal design that enables you to use multiple interfaces to control the same virtual machines. For example, you can start a virtual machine with the VirtualBox Manager window and then stop it from the command line. With Oracle VirtualBox's support for the Remote Desktop Protocol (RDP), you can even run virtual machines remotely on a headless server and have all the graphical output redirected over the network.

The following front ends are shipped in the standard Oracle VirtualBox package:

• VirtualBox. This is the VirtualBox Manager, a graphical user interface that uses the Qt toolkit. This interface is described throughout this user guide. While this is the simplest and easiest front end to use, some of the more advanced Oracle VirtualBox features are not included.

• VBoxManage. A command-line interface for automated and detailed control of every aspect of Oracle VirtualBox. See VBoxManage.

• VBoxHeadless. A front end that produces no visible output on the host at all, but can act as a RDP server if the VirtualBox Remote Desktop Extension (VRDE) is installed and enabled for the VM. As opposed to the other graphical interfaces, the headless front end requires no graphics support. This is useful, for example, if you want to host your virtual machines on a headless Linux server that has no X Window system installed. See VBoxHeadless, the Remote Desktop Server.

• Separate mode. A front end that is based on VBoxHeadless, but does not require VRDE or an RDP viewer. See Separate Mode.

If the above front ends still do not satisfy your particular needs, it is possible to create yet another front end to the complex virtualization engine that is the core of Oracle VirtualBox, as the Oracle VirtualBox core neatly exposes all of its features in a clean API. See Oracle VirtualBox Programming Interfaces.

The following limitations apply when using an Arm platform host:

• Virtual machines must use an Arm-based guest operating system. Running an x86-based guest operating system on an Arm host platform is not supported.

• Only VMSVGA is supported as a graphics controller.

• Unattended installation isn't available.

• The following System page settings aren't available for Arm guests:

  • Motherboard tab: Chipset, TPM

  • Processor tab: Extended Features such as Enable PAE/NX, Enable Nested VT-x/AMD-V

Intel host CPUs must have SSE2 (Streaming SIMD Extensions 2).

The Preferences window offers a selection of settings, which apply to all virtual machines of the current user.

To display the Preferences window, do either of the following:

• Select File, Preferences.

• Click Preferences on the Welcome screen in VirtualBox Manager.

The following settings are available:

• General. Enables you to specify the default folder or directory for VM files, and the VRDP Authentication Library.

• Input. Enables you to specify keyboard shortcuts, both in VirtualBox Manager and in individual VMs. For example you might want to specify a different Host key. This is the key that toggles whether the cursor is in the focus of the VM or the Host OS windows, see Capturing and Releasing Keyboard and Mouse. The Host key is also used to trigger certain VM actions, see Typing Special Characters.

• Update. Enables you to specify various settings for Automatic Updates.

• Language. Enables you to specify the language used for menus, labels, and text in VirtualBox Manager.

• Display. Enables you to specify the screen resolution, and its width and height. A default scale factor can be specified for all guest screens.

  A default font scaling factor can be set for all guest screen displays.

  Other extended features can be selected, to ensure that guest screens work well with the host display.

• Proxy. Enables you to configure an HTTP proxy server.

• Interface. Enables you to select a color theme for the VirtualBox Manager user interface.

  Note:

  This setting is only available on Windows host platforms.

When you use VirtualBox Manager to configure settings for virtual machines, you can select an experience level for the user interface. The following experience levels are available:

• Basic. Only a limited number of settings and tools are shown. Workflows are used to display settings and configuration options. This is the default setting for new installations.

  This level is suitable for a first time user of Oracle VirtualBox.

• Expert. All available settings and tools are shown.

  Single pages show all settings and configuration options. This is the default setting for upgrades when a user already has at least one saved VM.

  This level is suitable for an experienced user who needs more control of virtual machine settings.

Experience levels can be configured in the following places in VirtualBox Manager:

• The Welcome screen, for new installations only.

• The Preferences window.

• The Settings window for a virtual machine.

Wherever you set it, the preference applies throughout VirtualBox Manager.

In the left pane of the VirtualBox Manager window, click the Menu icon in the Tools banner located above the machine list. The Global Tools menu is displayed.

A drop-down list enables you to select from the following global tools:

• Welcome. Displays the VirtualBox Manager welcome message. The VirtualBox Manager toolbar is also included, to enable you to get started with using Oracle VirtualBox.

• Extensions. Displays the Extension Pack Manager tool. This tool is used to install and uninstall Oracle VirtualBox Extension Packs. See The Extension Pack Manager.

• Media. Displays the Virtual Media Manager tool. This tool is used to manage the disk images used by Oracle VirtualBox. See The Virtual Media Manager.

• Network. Displays the Network Manager tool. This tool is used to create and configure some types of networks used by Oracle VirtualBox. See Network Manager.

• Cloud. Displays the Cloud Profile Editor tool. This tool is used to configure connections to a cloud service, such as Oracle Cloud Infrastructure. See Using the Cloud Profile Manager.

• Activities. Displays the VM Activity Overview tool. This tool is used to monitor performance and resource usage of virtual machines. See Monitoring of Virtual Machines.

The Pin icon is used to keep the Tools banner visible as you scroll down the entries in the machine list.

If you choose Unattended guest OS Installation, Oracle VirtualBox installs the OS on the new virtual machine (VM) automatically. You must supply certain configuration options to be used in the installation.

See also Using VBoxManage Commands for Unattended Guest Installation for details of how to configure unattended installation from the command line.

1. Enter the Username and Password for a default user on the guest OS.

2. For Windows guests, enter the Product Key supplied with Windows.

3. Enter the Hostname for the VM. By default, this is the same as the VM name.

4. Enter the Domain Name for the VM.

5. Select Install in Background if you want to enable headless mode for the VM rather than using a graphical user interface.
6. Unattended Guest Additions installation is available for some x86 guests. Select Guest Additions if you would like Oracle VirtualBox to install the Guest Additions after the OS. Download the Guest Additions installation ISO to the host, and select the file location.
7. Click Next to Set Up VM Hardware.

1. For Base Memory, select the amount of RAM that Oracle VirtualBox should allocate to the virtual machine (VM) every time it is started. The guest OS will report this size as the VM's installed RAM.
   CAUTION:

   Choose this setting carefully. The memory you give to the VM will not be available to your host OS while the VM is running.

   Do not specify more than you can spare, whilst ensuring you allocate enough for your guest OS and applications to run properly. For example, if your host machine has 4 GB of RAM and you enter 2048 MB as the base memory for a VM, you will have 2 GB left for all the other software on your host while that VM is running.

   A guest OS may require at least 1 or 2 GB of memory to install and boot up. If you intend to run more than one VM at a time, plan accordingly. A VM will not start if it does not have enough RAM to boot.

   Always ensure that the host OS has enough RAM remaining. If insufficient RAM remains, the system might excessively swap memory to the hard disk, which will effectively bring the host system to a standstill.

2. For Processor(s), select the number of virtual processors to assign to the VM. Do not assign more than half of the total processor threads from the host machine.
3. Select Enable EFI if you want to enable Extensible Firmware Interface (EFI) booting for the guest OS.
4. Click Next to Specify a Virtual Hard Disk.

There are many ways in which Oracle VirtualBox can provide hard disk space to a VM, see Virtual Storage.

The most common way is to use a virtual hard disk. This is a large image file on your physical hard disk, whose contents Oracle VirtualBox presents to your VM as if it were a complete hard disk. You can copy this file to another host, and use it with another Oracle VirtualBox VM.

To prevent your physical hard disk on the host OS from filling up, Oracle VirtualBox limits the size of the image file. But the image file must be large enough to hold the contents of the guest OS and the applications you want to install. For a Windows or Linux guest, you will probably need several gigabytes for any serious use. The size limit of the image file can be changed later, see VBoxManage modifymedium.

When you start a VM for the first time the OS installation process is started automatically, using the ISO image file specified in the Create Virtual Machine workflow.

Follow the onscreen instructions to install your OS.

A status bar is displayed at the bottom of the virtual machine window. The status bar contains icons that enable you to view and change settings for the virtual machine, as follows:

• Highlight an icon to show details of the current settings.

• Right-click an icon to change a setting.

  Some settings, such as audio, can be changed directly by right-clicking the status bar icon. For other settings, you select from the displayed menu options.

See Configuring Virtual Machines for detailed information about the available virtual machine settings.

Table 2 describes the icons on the status bar.

Table 2. Virtual Machine Status Bar Icons. Describes icons on the status bar located at the bottom of the virtual machine window

Icon	Description
	Storage (SATA) Settings for attached SATA storage devices, such as hard disk drives. See also Storage Settings.
	Storage (IDE) Settings for attached IDE storage devices, such as optical CD-ROM drives. See also Storage Settings. Right-click to show options for adding and removing IDE devices. See also Changing Removable Media.
	Audio Settings for audio output and audio input. Right-click to change a setting. The status bar icon is updated automatically to show which settings are enabled. See also Audio Settings.
	Network Settings for attached network adapters. Right-click to connect or disconnect a network adapter. See also Network Settings.
	USB Settings for attached USB devices. Right-click to select from the available USB devices on the host and to specify a USB filter. See also USB Settings.
	Shared Folders Settings for shared folders. Right-click to change shared folder settings or to add a new shared folder. See also Shared Folders.
	Display Settings for the virtual machine display. Right-click to show options for resizing and scaling the display. See also Resizing the Machine's Window.
	Recording Settings for video and audio recording. Right-click to show options to enable and disable recording, or to change recording settings. To enable recording, right-click the status bar icon and select the Recording option. The icon changes to show a movie reel animation, as follows: To disable recording, right-click the status bar icon and deselect the Recording option. The icon changes back to the default image. See also Recording Tab.
	Processor Settings for the CPU used by the virtual machine. The colored bar in the icon indicates current processor activity. Red indicates high CPU usage, Green indicates low CPU usage. A green turtle icon indicates that a native hypervisor, such as Hyper-V, is running on the host. See also Processor Tab.
	Mouse Integration Settings for capturing the host mouse pointer. The icon indicates whether mouse integration is on (green arrow) or off (yellow arrow) and whether the pointer is captured (mouse icon colored) or not (mouse icon gray). Right-click to enable or disable mouse integration. See also Capturing and Releasing Keyboard and Mouse.
	Host Key Settings for capturing the host keyboard. The arrow on the icon is green if the keyboard is captured, and black if not. The background is blue if the host key is not pressed, and white when it is pressed. A check icon appears when the VM is waiting for a host key combination to be typed. The current host key is displayed to the right of the icon. Right-click to show options for configuring the host key combination and other keyboard shortcuts. Right-click to insert a special key combination, such as Ctrl-Alt-Del. See also Typing Special Characters.

Oracle VirtualBox provides a virtual USB tablet device to new virtual machines through which mouse events are communicated to the guest OS. If you are running a modern guest OS that can handle such devices, mouse support may work out of the box without the mouse being captured as described below. See Motherboard Tab.

Otherwise, if the virtual machine detects only standard PS/2 mouse and keyboard devices, since the OS in the virtual machine does not know that it is not running on a real computer, it expects to have exclusive control over your keyboard and mouse. But unless you are running the VM in full screen mode, your VM needs to share keyboard and mouse with other applications and possibly other VMs on your host.

After installing a guest OS and before you install the Guest Additions, described in Guest Additions, either your VM or the rest of your computer can own the keyboard and the mouse. Both cannot own the keyboard and mouse at the same time. You will see a second mouse pointer which is always confined to the limits of the VM window. You activate the VM by clicking inside it.

To return ownership of keyboard and mouse to your host OS, Oracle VirtualBox reserves a special key on your keyboard: the Host key. By default, this is the right Ctrl key on your keyboard. On a Mac host, the default Host key is the left Command key. You can change this default using the Preferences window. See Oracle VirtualBox Preferences. The current setting for the Host key is always displayed at the bottom right of your VM window.

Figure 1. Host Key Setting on the Virtual Machine Status Bar

This means the following:

• Your keyboard is owned by the VM if the VM window on your host desktop has the keyboard focus. If you have many windows open in your guest OS, the window that has the focus in your VM is used. This means that if you want to enter text within your VM, click the title bar of your VM window first.

  To release keyboard ownership, press the Host key. As explained above, this is typically the right Ctrl key.

  Note that while the VM owns the keyboard, some key sequences, such as Alt+Tab, will no longer be seen by the host, but will go to the guest instead. After you press the Host key to reenable the host keyboard, all key presses will go through the host again, so that sequences such as Alt+Tab will no longer reach the guest. For technical reasons it may not be possible for the VM to get all keyboard input even when it does own the keyboard. Examples of this are the Ctrl+Alt+Del sequence on Windows hosts or single keys grabbed by other applications on X11 hosts such as the GNOME desktop Locate Pointer feature.

• Your mouse is owned by the VM only after you have clicked in the VM window. The host mouse pointer will disappear, and your mouse will drive the guest's pointer instead of your normal mouse pointer.

  Note that mouse ownership is independent of that of the keyboard. Even after you have clicked on a titlebar to be able to enter text into the VM window, your mouse is not necessarily owned by the VM yet.

  To release ownership of your mouse by the VM, press the Host key.

As this behavior is inconvenient, Oracle VirtualBox provides a set of tools and device drivers for guest systems called the Oracle VirtualBox Guest Additions. These tools make VM keyboard and mouse operations much more seamless. Most importantly, the Guest Additions suppress the second "guest" mouse pointer and make your host mouse pointer work directly in the guest. See Guest Additions.

Some OSes expect certain key combinations to initiate certain procedures. The key combinations that you type into a VM might target the host OS, the Oracle VirtualBox software, or the guest OS. The recipient of these keypresses depends on a number of factors, including the key combination itself.

• Host OSes reserve certain key combinations for themselves. For example, you cannot use the Ctrl+Alt+Delete combination to reboot the guest OS in your VM, because this key combination is reserved by the host OS. Even though both Windows and Linux OSes can intercept this key combination, the host OS is rebooted automatically.

  On Linux and Oracle Solaris hosts, which use the X Window System, the key combination Ctrl+Alt+Backspace normally resets the X server and restarts the entire graphical user interface. As the X server intercepts this combination, pressing it will usually restart your host graphical user interface and kill all running programs, including Oracle VirtualBox, in the process.

  On Linux hosts supporting virtual terminals, the key combination Ctrl+Alt+Fx, where Fx is one of the function keys from F1 to F12, normally enables you to switch between virtual terminals. As with Ctrl+Alt+Delete, these combinations are intercepted by the host OS and therefore always switch terminals on the host.

  If, instead, you want to send these key combinations to the guest OS in the virtual machine, you will need to use one of the following methods:

  • Use the items in the Input, Keyboard menu of the virtual machine window. This menu includes the settings Insert Ctrl+Alt+Delete and Insert Ctrl+Alt+Backspace. However, the latter setting affects only Linux guests or Oracle Solaris guests.

    This menu also includes an option for inserting the Host key combination.

  • Use special key combinations with the Host key, which is normally the right Control key. Oracle VirtualBox then translates the following key combinations for the VM:

    • Host key + Del sends Ctrl+Alt+Del to reboot the guest OS.

    • Host key + Backspace sends Ctrl+Alt+Backspace to restart the graphical user interface of a Linux or Oracle Solaris guest.

    • Host key + Function key. For example, use this key combination to simulate Ctrl+Alt+Fx to switch between virtual terminals in a Linux guest.

• For some other keyboard combinations such as Alt+Tab to switch between open windows, Oracle VirtualBox enables you to configure whether these combinations will affect the host or the guest, if a virtual machine currently has the focus. This is a global setting for all virtual machines and can be found under File, Preferences, Input.

• A soft keyboard can be used to input key combinations in the guest. See Soft Keyboard.

While a virtual machine is running, you can change removable media in the Devices menu of the VM's window. Here you can select in detail what Oracle VirtualBox presents to your VM as a CD, DVD, or floppy drive.

The settings are the same as those available for the VM in the Settings window of VirtualBox Manager. But as the Settings window is disabled while the VM is in the Running or Saved state, the Devices menu saves you from having to shut down and restart the VM every time you want to change media.

Using the Devices menu, you can attach the host drive to the guest or select a floppy or DVD image, as described in Storage Settings.

The Devices menu also includes an option for creating a virtual ISO (VISO) from selected files on the host.

You can resize the VM's window while that VM is running. When you do, the window is scaled as follows:

• If you have scaled mode enabled, then the virtual machine's screen will be scaled to the size of the window. This can be useful if you have many machines running and want to have a look at one of them while it is running in the background. Alternatively, it might be useful to enlarge a window if the VM's output screen is very small, for example because you are running an old OS in it.

  To enable scaled mode, press Host key + C, or select Scaled Mode from the View menu in the VM window. To leave scaled mode, press Host key + C again.

  The aspect ratio of the guest screen is preserved when resizing the window. To ignore the aspect ratio, press Shift during the resize operation.

  See Known Limitations for additional remarks.

• If you have the Guest Additions installed and they support automatic resizing, the Guest Additions will automatically adjust the screen resolution of the guest OS. For example, if you are running a Windows guest with a resolution of 1024x768 pixels and you then resize the VM window to make it 100 pixels wider, the Guest Additions will change the Windows display resolution to 1124x768.

  See Guest Additions.

• Otherwise, if the window is bigger than the VM's screen, the screen will be centered. If it is smaller, then scroll bars will be added to the machine window.

When you click the Close button of your virtual machine window, at the top right of the window, just like you would close any other window on your system, Oracle VirtualBox asks you whether you want to save or power off the VM. As a shortcut, you can also press Host key + Q.

The difference between the three options is crucial. They mean the following:

• Save the machine state: With this option, Oracle VirtualBox freezes the virtual machine by completely saving its state to your local disk.

  When you start the VM again later, you will find that the VM continues exactly where it was left off. All your programs will still be open, and your computer resumes operation. Saving the state of a virtual machine is thus in some ways similar to suspending a laptop computer by closing its lid.

• Send the shutdown signal. This will send an ACPI shutdown signal to the virtual machine, which has the same effect as if you had pressed the power button on a real computer. This should trigger a proper shutdown mechanism from within the VM.

• Power off the machine: With this option, Oracle VirtualBox also stops running the virtual machine, but without saving its state.

  CAUTION:

  This is equivalent to pulling the power plug on a real computer without shutting it down properly. If you start the machine again after powering it off, your OS will have to reboot completely and may begin a lengthy check of its virtual system disks. As a result, this should not normally be done, since it can potentially cause data loss or an inconsistent state of the guest system on disk.

  As an exception, if your virtual machine has any snapshots, see Snapshots, you can use this option to quickly restore the current snapshot of the virtual machine. In that case, powering off the machine will discard the current state and any changes made since the previous snapshot was taken will be lost.

The Discard button in the VirtualBox Manager window discards a virtual machine's saved state. This has the same effect as powering it off, and the same warnings apply.

You may need to change the configuration of a Virtual Machine (VM) after it has been created. For example, you may want to add more memory.

Be careful when changing VM settings. It is possible to change all VM settings after installing a guest OS, but certain changes might prevent a guest OS from functioning correctly if done after installation.

The settings are described in detail in Configuring Virtual Machines.

Even more parameters are available when using the VBoxManage command line interface. See VBoxManage.

Create VM groups if you want to manage several VMs together, and perform functions on them collectively, as well as individually.

The following features are available for groups:

• Create a group using VirtualBox Manager. Do one of the following:

  • Drag a VM on top of another VM.

  • Select multiple VMs and select Group from the right-click menu.

• Create and manage a group using the command line. Do one of the following:

  • Create a group and assign a VM. For example:

    VBoxManage modifyvm "vm01" --groups "/TestGroup"

    This command creates a group TestGroup and attaches the VM vm01 to that group.

  • Detach a VM from the group, and delete the group if empty. For example:

    VBoxManage modifyvm "vm01" --groups ""

    This command detaches all groups from the VM vm01 and deletes the empty group.

• Create multiple groups. For example:

  VBoxManage modifyvm "vm01" --groups "/TestGroup,/TestGroup2"

  This command creates the groups TestGroup and TestGroup2, if they do not exist, and attaches the VM vm01 to both of them.

• Create nested groups, having a group hierarchy. For example:

  VBoxManage modifyvm "vm01" --groups "/TestGroup/TestGroup2"

  This command attaches the VM vm01 to the subgroup TestGroup2 of the TestGroup group.

• Use VirtualBox Manager menu options to control and manage all the VMs in a group. For example: Start, Pause, Reset, Close (save state, send shutdown signal, poweroff), Discard Saved State, Show in Explorer, Sort.

There are three operations related to snapshots, as follows:

1. Take a snapshot. This makes a copy of the machine's current state, to which you can go back at any given time later.

   • If your VM is running:

     Select Take Snapshot from the Machine menu in the VM window.

     The VM is paused while the snapshot is being created. After snapshot creation, the VM continues to run as normal.

   • If your VM is in either the Saved or the Powered Off state, as displayed next to the VM name in the machine list:

     Display the Snapshots window and do one of the following:

     • Click Take in the Snapshots window toolbar.

     • Right-click the Current State item in the list and select Take.

   A dialog is displayed, prompting you for a snapshot name. This name is purely for reference purposes, to help you remember the state of the snapshot. For example, a useful name would be Fresh installation from scratch, no Guest Additions, or Service Pack 3 just installed. You can also add a longer text description in the Snapshot Description field.

   Your new snapshot will then appear in the snapshots list. Underneath your new snapshot, you will see an item called Current State, signifying that the current state of your VM is a variation based on the snapshot you took earlier. If you later take another snapshot, you will see that they are displayed in sequence, and that each subsequent snapshot is derived from an earlier one.

   Oracle VirtualBox imposes no limits on the number of snapshots you can take. The only practical limitation is disk space on your host. Each snapshot stores the state of the virtual machine and thus occupies some disk space. See Snapshot Contents for details on what is stored in a snapshot.

2. Restore a snapshot. In the Snapshots window, select the snapshot you have taken and click Restore in the toolbar. By restoring a snapshot, you go back or forward in time. The current state of the machine is lost, and the machine is restored to the exact state it was in when the snapshot was taken.

   Note:

   Restoring a snapshot will affect the virtual hard drives that are connected to your VM, as the entire state of the virtual hard drive will be reverted as well. This means also that all files that have been created since the snapshot and all other file changes will be lost. In order to prevent such data loss while still making use of the snapshot feature, it is possible to add a second hard drive in write-through mode using the VBoxManage interface and use it to store your data. As write-through hard drives are not included in snapshots, they remain unaltered when a machine is reverted. See Special Image Write Modes.

   To avoid losing the current state when restoring a snapshot, you can create a new snapshot before the restore operation.

   By restoring an earlier snapshot and taking more snapshots from there, it is even possible to create a kind of alternate reality and to switch between these different histories of the virtual machine. This can result in a whole tree of virtual machine snapshots.

3. Delete a snapshot. This does not affect the state of the virtual machine, but only releases the files on disk that Oracle VirtualBox used to store the snapshot data, thus freeing disk space. To delete a snapshot, select the snapshot name in the Snapshots window and click Delete in the toolbar. Snapshots can be deleted even while a machine is running.

   Note:

   Whereas taking and restoring snapshots are fairly quick operations, deleting a snapshot can take a considerable amount of time since large amounts of data may need to be copied between several disk image files. Temporary disk files may also need large amounts of disk space while the operation is in progress.

   There are some situations which cannot be handled while a VM is running, and you will get an appropriate message that you need to perform this snapshot deletion when the VM is shut down.

Think of a snapshot as a point in time that you have preserved. More formally, a snapshot consists of the following:

• The snapshot contains a complete copy of the VM settings, including the hardware configuration, so that when you restore a snapshot, the VM settings are restored as well. For example, if you changed the hard disk configuration or the VM's system settings, that change is undone when you restore the snapshot.

  The copy of the settings is stored in the machine configuration, an XML text file, and thus occupies very little space.

• The complete state of all the virtual disks attached to the machine is preserved. Going back to a snapshot means that all changes that had been made to the machine's disks, file by file and bit by bit, will be undone. Files that were since created will disappear, files that were deleted will be restored, changes to files will be reverted.

  Strictly speaking, this is only true for virtual hard disks in "normal" mode. You can configure disks to behave differently with snapshots, see Special Image Write Modes. In technical terms, it is not the virtual disk itself that is restored when a snapshot is restored. Instead, when a snapshot is taken, Oracle VirtualBox creates differencing images which contain only the changes since the snapshot were taken. When the snapshot is restored, Oracle VirtualBox throws away that differencing image, thus going back to the previous state. This is both faster and uses less disk space. For the details, which can be complex, see Differencing Images.

  Creating the differencing image as such does not occupy much space on the host disk initially, since the differencing image will initially be empty and grow dynamically later with each write operation to the disk. The longer you use the machine after having created the snapshot, however, the more the differencing image will grow in size.

• If you took a snapshot while the machine was running, the memory state of the machine is also saved in the snapshot. This is in the same way that memory can be saved when you close a VM window. When you restore such a snapshot, execution resumes at exactly the point when the snapshot was taken.

  The memory state file can be as large as the memory size of the VM and will therefore occupy considerable disk space.

OVF is a cross-platform standard supported by many virtualization products which enables the creation of ready-made virtual machines that can then be imported into a hypervisor such as Oracle VirtualBox. Oracle VirtualBox makes OVF import and export easy to do, using VirtualBox Manager or the command-line interface.

Using OVF enables packaging of virtual appliances. These are disk images, together with configuration settings that can be distributed easily. This way one can offer complete ready-to-use software packages, including OSes with applications, that need no configuration or installation except for importing into Oracle VirtualBox.

Appliances in OVF format can appear in the following variants:

• They can come in several files, as one or several disk images, typically in the widely-used VMDK format. See Disk Image Files (VDI, VMDK, VHD, HDD). They also include a textual description file in an XML dialect with an .ovf extension. These files must then reside in the same directory for Oracle VirtualBox to be able to import them.

• Alternatively, the above files can be packed together into a single archive file, typically with an .ova extension. Such archive files use a variant of the TAR archive format and can therefore be unpacked outside of Oracle VirtualBox with any utility that can unpack standard TAR files.

The following steps show how to import an appliance in OVF format.

1. Double-click the OVF or OVA file.

   Oracle VirtualBox creates file type associations automatically for any OVF and OVA files on your host OS.

   The Appliance Settings page of the Import Virtual Appliance wizard is shown. This page shows the VMs described in the OVF or OVA file and enables you to change the VM settings.

2. By default, membership of VM groups is preserved on import for VMs that were initially exported from Oracle VirtualBox. You can change this behavior by using the Primary Group setting for the VM.

   The following global settings apply to all of the VMs that you import:

   • Base Folder: Specifies the directory on the host in which to store the imported VMs.

     If an appliance has multiple VMs, you can specify a different directory for each VM by editing the Base Folder setting for the VM.

   • MAC Address Policy: Reinitializes the MAC addresses of network cards in your VMs prior to import, by default. You can override the default behavior and preserve the MAC addresses on import.

   • Import Hard Drives as VDI: Imports hard drives in the VDI format rather than in the default VMDK format.

3. Click Finish to import the appliance.

   Oracle VirtualBox copies the disk images and creates local VMs with the settings described on the Appliance Settings page. The imported VMs are shown in the list of VMs in VirtualBox Manager.

   Because disk images are large, the VMDK images that are included with virtual appliances are shipped in a compressed format that cannot be used directly by VMs. So, the images are first unpacked and copied, which might take several minutes.

You can use the VBoxManage import command to import an appliance. See VBoxManage import.

The following steps show how to export an appliance in OVF format.

1. Select File, Export Appliance to display the Export Virtual Appliance wizard.

   On the initial Virtual Machines page, you can combine several VMs into an OVF appliance.

   Select one or more VMs to export, and click Next.

2. The Format Settings page enables you to configure the following settings:

   • Format: Selects the Open Virtualization Format value for the output files.

     The Oracle Cloud Infrastructure value exports the appliance to Oracle Cloud Infrastructure. See Exporting an Appliance to Oracle Cloud Infrastructure.

   • File: Selects the location in which to store the exported files.

   • MAC Address Policy: Specifies whether to retain or reassign network card MAC addresses on export.

   • Write Manifest File: Enables you to include a manifest file in the exported archive file.

   • Include ISO Image Files: Enables you to include ISO image files in the exported archive file.

3. Click Next to show the Appliance Settings page.

   You can edit settings for the virtual appliance. For example, you can change the name of the virtual appliance or add product information, such as vendor details or license text.

   Double-click the appropriate field to change its value.

4. Click Finish to begin the export process. Note that this operation might take several minutes.

You can use the VBoxManage export command to export an appliance. See VBoxManage export.

Perform the following configuration steps before using Oracle VirtualBox to integrate with your Oracle Cloud Infrastructure account.

1. Install the Extension Pack. Cloud integration features are only available when you install the Oracle VirtualBox Extension Pack. See Installing Oracle VirtualBox and Extension Packs.

2. Create a key pair. Generate an API signing key pair that is used for API requests to Oracle Cloud Infrastructure. See Creating an API Signing Key Pair.

   Upload the public key of the key pair from your client device to the cloud service. See Uploading the Public Key to Oracle Cloud Infrastructure.

3. Create a cloud profile. The cloud profile contains resource identifiers for your cloud account, such as your user OCID, and details of your key pair. See Creating a Cloud Profile.

To use the cloud integration features of Oracle VirtualBox, you must generate an API signing key pair that is used for API requests to Oracle Cloud Infrastructure.

Your API requests are signed with your private key, and Oracle Cloud Infrastructure uses the public key to verify the authenticity of the request. You must upload the public key to the Oracle Cloud Infrastructure Console.

1. (Optional) Create a .oci directory to store the key pair.

   $ mkdir ~/.oci

   The key pair is usually installed in the .oci folder in your home directory. For example, ~/.oci on a Linux system.

2. Generate the private key.

   Use the openssl command.

   • To generate a private key with a passphrase (prompt for passphrase):

     $ openssl genrsa -out ~/.oci/oci_api_key.pem -aes256 2048 

   • To generate a private key with a passphrase entered on the command line as an argument:

     $ openssl genrsa -aes256 -passout pass:user_passphrase -out ~/.oci/oci_api_key.pem 2048

   • To generate a private key without a passphrase:

     $ openssl genrsa -out ~/.oci/oci_api_key.pem 2048

3. Change permissions for the private key.

   $ chmod 600 ~/.oci/oci_api_key.pem

   Generate the public key.

   $ openssl rsa -pubout -in ~/.oci/oci_api_key.pem -out ~/.oci/oci_api_key_public.pem

   Enter the passphrase when prompted, if you set one.

Use the following steps to upload your public key to Oracle Cloud Infrastructure.

1. Log in to the Oracle Cloud Console.

2. Display the User Settings page.

   Click Profile, User Settings.

3. Display your current API signing keys.

   Click Resources, API Keys.

4. Upload the public key.

   Click Add Public Key.

   The Add Public Key dialog is displayed.

5. Select one of the following options:

   • Choose Public Key File. This option enables you to browse to the public key file on your local hard disk.

   • Paste Public Keys. This option enables you to paste the contents of the public key file into the window in the dialog box.

6. Click Add to upload the public key.

Oracle VirtualBox uses a cloud profile to connect to Oracle Cloud Infrastructure. A cloud profile is a text file that contains details of your key files and Oracle Cloud Identifier (OCID) resource identifiers for your cloud account, such as the following:

• Fingerprint of the public key. To obtain the fingerprint, you can use the openssl command:

  $ openssl rsa -pubout -outform DER -in ~/.oci/oci_api_key.pem | openssl md5 -c

• Location of the private key on the client device. Specify the full path to the private key.

• (Optional) Passphrase for the private key. This is only required if the key is encrypted.

• Region. Shown on the Oracle Cloud Infrastructure Console. Click Administration, Tenancy Details.

• Tenancy OCID. Shown on the Oracle Cloud Infrastructure Console. Click Administration, Tenancy Details.

  A link enables you to copy the Tenancy OCID.

• Compartment OCID. Shown on the Oracle Cloud Infrastructure Console. Click Identity, Compartments.

  A link enables you to copy the Compartment OCID.

• User OCID. Shown on the Oracle Cloud Infrastructure Console. Click Profile, User Settings.

  A link enables you to copy the User OCID.

You can create a cloud profile in the following ways:

• Automatically, by using the Cloud Profile Manager. See Using the Cloud Profile Manager.

  The Cloud Profile Manager is a VirtualBox Manager tool that enables you to create, edit, and manage cloud profiles for your cloud service accounts.

• Automatically, by using the VBoxManage cloudprofile command. See VBoxManage cloudprofile.

• Manually, by creating an oci_config file in your Oracle VirtualBox global configuration directory. For example, this is $HOME/.config/VirtualBox/oci_config on a Linux host.

• Manually, by creating a config file in your Oracle Cloud Infrastructure configuration directory. For example, this is $HOME/.oci/config on a Linux host.

  This is the same file that is used by the Oracle Cloud Infrastructure command line interface.

  Oracle VirtualBox automatically uses the config file if no cloud profile file is present in your global configuration directory. Alternatively, you can import this file manually into the Cloud Profile Manager.

To open the Cloud Profile Manager click File, Cloud Profile Manager in VirtualBox Manager.

You can use the Cloud Profile Manager in the following ways:

• To create a new cloud profile automatically.

• To create a cloud profile by importing settings from your Oracle Cloud Infrastructure configuration file.

This section describes how you can use Oracle VirtualBox with Oracle Cloud Infrastructure to do the following tasks:

• Create, add, and manage Oracle Cloud Infrastructure cloud instances using VirtualBox Manager. See Using Cloud Virtual Machines.

• Export an Oracle VirtualBox VM to Oracle Cloud Infrastructure. See Exporting an Appliance to Oracle Cloud Infrastructure.

• Import a cloud instance into Oracle VirtualBox. See Importing an Instance from Oracle Cloud Infrastructure.

• Connect from a local VM to an Oracle Cloud Infrastructure cloud subnet. See Using a Cloud Network.

• Use the VBoxManage commands to integrate with Oracle Cloud Infrastructure and perform cloud operations. See Using VBoxManage Commands With Oracle Cloud Infrastructure.

A cloud virtual machine (cloud VM) is a type of VM that represents an instance on a cloud service. Cloud VMs are shown in the machine list in VirtualBox Manager, in the same way as local VMs are.

By using cloud VMs you can create, manage, and control your Oracle Cloud Infrastructure instances from VirtualBox Manager.

Cloud VMs can be used to do the following tasks in Oracle Cloud Infrastructure:

• Create a new Oracle Cloud Infrastructure instance. See Creating a New Cloud VM.

• Use an existing Oracle Cloud Infrastructure instance. See Adding a Cloud VM.

• Copy an existing Oracle Cloud Infrastructure instance. See Cloning a Cloud VM.

• Configure an Oracle Cloud Infrastructure instance. You can change settings for the instance, such as display name. See Changing Settings for a Cloud VM.

• Control an Oracle Cloud Infrastructure instance. Stop, start, and terminate the instance. See Controlling a Cloud VM

• Create a console connection to an Oracle Cloud Infrastructure instance. See Creating an Instance Console Connection for a Cloud VM.

Oracle VirtualBox supports the export of VMs to an Oracle Cloud Infrastructure service. The exported VM is stored on Oracle Cloud Infrastructure as a custom Linux image. You can configure whether a cloud instance is created and started after the export process has completed.

Use the following steps to export a VM to Oracle Cloud Infrastructure:

1. Select File, Export Appliance.

2. Select a VM to export, and then click Next to display the Format Settings page.

3. From the Format drop-down list, select Oracle Cloud Infrastructure.

4. In the Profile drop-down list, select the cloud profile used for your Oracle Cloud Infrastructure account.

5. In the Machine Creation field, select an option to configure settings for the cloud instance created when you export to Oracle Cloud Infrastructure. The options enable you to do one of the following:

   • Configure settings for the cloud instance after you have finished exporting the VM.

   • Configure settings for the cloud instance before you start to export the VM.

   • Do not create a cloud instance when you export the VM.

   Click Next to make an API request to the Oracle Cloud Infrastructure service and open the Appliance Settings page.

6. (Optional) Edit storage settings used for the exported virtual machine in Oracle Cloud Infrastructure. You can change the following settings:

   • The name of the bucket used to store the exported files.

   • Whether to store the custom image in Oracle Cloud Infrastructure.

   • The display name for the custom image in Oracle Cloud Infrastructure.

   • The launch mode for the cloud instance.

     Paravirtualized mode gives improved performance and is suitable for most Oracle VirtualBox VMs.

     Emulated mode is suitable for legacy OS images.

   Click Finish to continue.

7. (Optional) Depending on the selection in the Machine Creation field, the Appliance Settings page may be displayed before or after export. This screen enables you to configure settings for the cloud instance, such as Shape and Disk Size.

   Click Finish. The VM is exported to Oracle Cloud Infrastructure.

   Depending on the Machine Creation setting, a cloud instance may be started after upload to Oracle Cloud Infrastructure is completed.

8. Monitor the export process by using the Oracle Cloud Console.

You can also use the VBoxManage export command to export a VM to Oracle Cloud Infrastructure. See VBoxManage export.

Perform the following steps to import a cloud instance from Oracle Cloud Infrastructure into Oracle VirtualBox:

1. Select File, Import Appliance.

   In the Source drop-down list, select Oracle Cloud Infrastructure.

   In the Profile drop-down list, select the cloud profile for your Oracle Cloud Infrastructure account.

   Choose the required cloud instance from the list in the Machines field.

   Click Next to make an API request to the Oracle Cloud Infrastructure service and display the Appliance Settings page.

2. (Optional) Edit settings for the new local virtual machine.

   For example, you can edit the Name and Description that will be used for the VM.

   Click Finish to import the instance from Oracle Cloud Infrastructure.

3. Monitor the import process by using the Oracle Cloud Console.

You can also use the VBoxManage import command to import an instance from Oracle Cloud Infrastructure. See VBoxManage import.

A cloud network is a type of network that can be used for connections from a local VM to a remote Oracle Cloud Infrastructure cloud instance.

To create and use a cloud network, do the following:

1. Set up a virtual cloud network on Oracle Cloud Infrastructure.

   The following steps create and configure a virtual cloud network (VCN) on Oracle Cloud Infrastructure. The VCN is used to tunnel network traffic across the cloud.

   1. Ensure that you have a cloud profile for connecting to Oracle Cloud Infrastructure. See Creating a Cloud Profile.

   2. Run the following VBoxManage cloud command:

      VBoxManage cloud --provider="OCI" --profile="vbox-oci" network setup

      where vbox-oci is the name of your cloud profile.

      Other options are available for the VBoxManage cloud network setup command, to enable you to configure details for the VCN. For example, you can configure the operating system used for the cloud gateway instance and the IP address range used by the tunneling network. See VBoxManage cloud.

      For best results, use an Oracle Linux 7 instance for the cloud gateway. This is the default option.

2. Register the new cloud network with Oracle VirtualBox.

   Use the Cloud Networks tab in the Network Manager tool. See Cloud Networks Tab.

3. Add cloud network adaptors to the local VMs that will use the cloud network. See Cloud Networks.

This section includes some examples of how VBoxManage commands can be used to integrate with Oracle Cloud Infrastructure and perform common cloud operations.

Creating a Cloud Profile

To create a cloud profile called vbox-oci:

VBoxManage cloudprofile --provider "OCI" --profile="vbox-oci" add \
--clouduser="ocid1.user.oc1..."  --keyfile="/home/username/.oci/oci_api_key.pem" \
--tenancy="ocid1.tenancy.oc1..."  --compartment="ocid1.compartment.oc1..."  --region="us-ashburn-1"

The new cloud profile is added to the oci_config file in your Oracle VirtualBox global configuration directory. For example, this is $HOME/.VirtualBox/oci_config on a Windows host.

Listing Cloud Instances

To list the instances in your Oracle Cloud Infrastructure compartment:

VBoxManage cloud --provider="OCI" --profile="vbox-oci" list instances

Exporting an Oracle VirtualBox VM to the Cloud

To export a VM called myVM and create a cloud instance called myVM_Cloud:

VBoxManage export myVM --output OCI:// --cloud 0 --vmname myVM_Cloud \
--cloudprofile "vbox-oci" --cloudbucket myBucket \
--cloudshape VM.Standard2.1 --clouddomain US-ASHBURN-AD-1 --clouddisksize 50  \
--cloudocivcn ocid1.vcn.oc1... --cloudocisubnet ocid1.subnet.oc1... \
--cloudkeepobject true --cloudlaunchinstance true --cloudpublicip true
      

Importing a Cloud Instance Into Oracle VirtualBox

To import a cloud instance and create an Oracle VirtualBox VM called oci_Import:

VBoxManage import OCI:// --cloud --vmname oci_Import --memory 4000
--cpus 3 --ostype FreeBSD_64 --cloudprofile "vbox-oci"
--cloudinstanceid ocid1.instance.oc1... --cloudbucket myBucket
  

Creating a New Cloud Instance From a Custom Image

To create a new cloud instance from a custom image on Oracle Cloud Infrastructure:

VBoxManage cloud --provider="OCI" --profile="vbox-oci" instance create \
--domain-name="oraclecloud.com" --image-id="ocid1.image.oc1..." --display-name="myInstance" \
--shape="VM.Standard2.1" --subnet="ocid1.subnet.oc1..."

Terminating a Cloud Instance

To terminate an instance in your compartment on Oracle Cloud Infrastructure:

VBoxManage cloud --provider="OCI" --profile="vbox-oci" instance terminate \
--id="ocid1.instance.oc1..." 

Showing Cloud Instance Performance Metrics

To show CPU usage metrics for a cloud instance:

VBoxManage cloud --provider="OCI" --profile="vbox-oci" instance metricdata \
--id="ocid1.instance.oc1..." --metric-name="CpuUtilization"

For more details about the available commands for cloud operations, see VBoxManage cloud.

1. Display the soft keyboard.

   In the guest VM window, select Input, Keyboard, Soft Keyboard.

2. Select the required keyboard layout.

   The name of the current keyboard layout is displayed in the toolbar of the soft keyboard window. This is the previous keyboard layout that was used.

   Click the Layout List icon in the toolbar of the soft keyboard window. The Layout List window is displayed.

   Select the required keyboard layout from the entries in the Layout List window.

   The keyboard display graphic is updated to show the available input keys.

3. Use the soft keyboard to enter keyboard characters on the guest.

   • Modifier keys such as Shift, Ctrl, and Alt are available on the soft keyboard. Click once to select the modifier key, click twice to lock the modifier key.

     The Reset the Keyboard and Release All Keys icon can be used to release all pressed modifier keys, both on the host and the guest.

   • To change the look of the soft keyboard, click the Settings icon in the toolbar. You can change colors used in the keyboard graphic, and can hide or show sections of the keyboard, such as the NumPad or multimedia keys.

You can use one of the supplied default keyboard layouts as the starting point to create a custom keyboard layout.

1. Display the Layout List.

   Click the Layout List icon in the toolbar of the soft keyboard window.

2. Make a copy of an existing keyboard layout.

   Highlight the required layout and click the Copy the Selected Layout icon.

   A new layout entry with a name suffix of -Copy is created.

3. Edit the new keyboard layout.

   Highlight the new layout in the Layout List and click the Edit the Selected Layout icon.

   Enter a new name for the layout.

   Edit keys in the new layout. Click the key that you want to edit and enter new key captions in the Captions fields.

   The keyboard graphic is updated with the new captions.

4. (Optional) Save the layout to a file. This means that your custom keyboard layout will be available for future use.

   Highlight the new layout in the Layout List and click the Save the Selected Layout into File icon.

   Any custom layouts that you create can later be removed from the Layout List, by highlighting and clicking the Delete the Selected Layout icon.

The VM Activity Overview tool displays several performance metrics for all running virtual machines and cloud VM instances, and for the host system. This provides an overview of system resources used by individual virtual machines and the host system.

To display the VM Activity Overview tool, open the global Tools menu and click Activities. The VM Activity Overview window is shown.

• To show metrics for all virtual machines, including those that are not running, right-click the list of virtual machines and select List All Virtual Machines.
• To show metrics for cloud VMs, right-click the list of virtual machines and select Show Cloud Virtual Machines.
• To configure the set of metrics to be shown, click Columns in the toolbar. You can then sort the list of virtual machines by a particular metric.
• To see more performance information for a virtual machine, select the VM name and click VM Activity in the toolbar. The VM Activity tab of the Session Information dialog is shown, see Session Information Dialog.

The Session Information dialog includes multiple tabs that show important configuration and runtime information for the guest system. The tabs are as follows:

• Configuration Details. Displays the system configuration of the virtual machine in a tabular format. The displayed information includes details such as storage configuration and audio settings.

• Runtime Information. Displays runtime information for the guest session in a tabular format similar to the Configuration Details tab.

• VM Activity. Includes several time series charts which monitor guest resource usage including CPU, RAM, Disk I/O, and Network. Note that the RAM chart requires the Guest Additions to be running on the guest system. The VM Activity tab can also be accessed directly from the VM Activity Overview tool. See VM Activity Overview.

• Guest Control. Details of processes used by the Guest Control File Manager. See Guest Control File Manager.

To display session information for a guest VM or a cloud VM, select the VM name in the machine list and click Activity in the machine tools menu.

Every time you start up a VM, Oracle VirtualBox creates a log file that records system configuration and events. The Log Viewer is a VirtualBox Manager tool that enables you to view and analyze system logs.

To display the Log Viewer, do either of the following:

• Click the VM name in the machine list and select Logs from the machine tools menu.

• In the VM, select Machine, Show Log.

Log messages for the VM are displayed in tabs in the Log Viewer window. See Collecting Debugging Information for details of the various log files generated by Oracle VirtualBox.

If you select multiple VMs in the machine list, logs are listed for each VM.

The toolbar of the Log Viewer includes the following options:

• Save: Exports the contents of the selected log file to a text file. Specify the destination filename and location in the displayed dialog.

• Find: Searches for a text string in the log file.

• Filter: Uses filter terms to display specific types of log messages. Common log message terms used by Oracle VirtualBox, such as Audio and NAT, are included by default. Select one or more terms from the drop-down list. To add your own filter term, enter the text string in the text box field.

• Bookmark: Saves the location of a log message, enabling you to find it quickly. To create a bookmark, either click the line number, or select some text and then click Bookmark.

• Preferences: Configures the text display used in the log message window.

• Refresh: Refreshes the log file you are currently viewing. Only log messages in the current tab are updated.

• Reload: Refreshes all log files. Log messages in every tab are updated.

• Settings: Displays the Settings window for the VM, enabling you to make configuration changes.

• Discard: For a running VM, discards the saved state for the VM and closes it down.

• Show/Start: For a running VM, Show displays the VM window. For a stopped VM, Start displays options for powering up the VM.

For the various versions of Windows that are supported as host operating systems, please refer to Available Installation Packages.

In addition, Windows Installer must be present on your system. This should be the case for all supported Windows platforms.

The installation directory on Windows hosts must meet certain security requirements, in order to be accepted by the Windows installer.

This also applies for upgrades of Oracle VirtualBox.

        Users               S-1-5-32-545:(OI)(CI)(RX)
        Users               S-1-5-32-545:(DE,WD,AD,WEA,WA)
        Authenticated Users S-1-5-11:(OI)(CI)(RX)
        Authenticated Users S-1-5-11:(DE,WD,AD,WEA,WA)
      

      icacls <Directory> /reset /t /c
      icacls <Directory> /inheritance:d /t /c
      icacls <Directory> /grant *S-1-5-32-545:(OI)(CI)(RX)
      icacls <Directory> /deny  *S-1-5-32-545:(DE,WD,AD,WEA,WA)
      icacls <Directory> /grant *S-1-5-11:(OI)(CI)(RX)
      icacls <Directory> /deny  *S-1-5-11:(DE,WD,AD,WEA,WA)
      

The Oracle VirtualBox installation can be started in either of the following ways:

• By double-clicking on the executable file.

• By entering the following command:

  VirtualBox-<version>-<revision>-Win.exe -extract

  This will extract the installer into a temporary directory, along with the .MSI file. Run the following command to perform the installation:

  msiexec /i VirtualBox-<version>-<revision>-Win.msi

Using either way displays the installation Welcome dialog and enables you to choose where to install Oracle VirtualBox, and which components to install. In addition to the Oracle VirtualBox application, the following components are available:

• USB support. This package contains special drivers for your Windows host that Oracle VirtualBox requires to fully support USB devices inside your virtual machines.

• Networking. This package contains extra networking drivers for your Windows host that Oracle VirtualBox needs to support Bridged Networking. This enables your VM's virtual network cards to be accessed from other machines on your physical network.

• Python support. This package contains Python scripting support for the Oracle VirtualBox API, see Oracle VirtualBox Programming Interfaces. For this to work, an already working Windows Python installation on the system is required.

  See, for example: http://www.python.org/download/windows/.

  Note:

  Python version 3 is required. Python version 2.x is no longer supported.

Depending on your Windows configuration, you may see warnings about unsigned drivers, or similar. Click Continue for these warnings, as otherwise Oracle VirtualBox might not function correctly after installation.

The installer will create an Oracle VirtualBox group in the Windows Start menu, which enables you to launch the application and access its documentation.

With standard settings, Oracle VirtualBox will be installed for all users on the local system. If this is not wanted, you must invoke the installer by first extracting as follows:

VirtualBox.exe -extract

Then, run either of the following commands on the extracted .MSI file. This will install Oracle VirtualBox only for the current user.

VirtualBox.exe -msiparams ALLUSERS=2

msiexec /i VirtualBox-<version>-Win.msi ALLUSERS=2

If you do not want to install all features of Oracle VirtualBox, you can set the optional ADDLOCAL parameter to explicitly name the features to be installed. The following features are available:

VBoxApplication

Main binaries of Oracle VirtualBox.

Note:

This feature must not be absent, since it contains the minimum set of files to have working Oracle VirtualBox installation.

VBoxUSB

USB support.

VBoxNetwork

All networking support. This includes the VBoxNetworkFlt and VBoxNetworkAdp features.

VBoxNetworkFlt

Bridged networking support.

VBoxNetworkAdp

Host-only networking support

VBoxPython

Python support

For example, to only install USB support along with the main binaries, run either of the following commands:

VirtualBox.exe -msiparams ADDLOCAL=VBoxApplication,VBoxUSB

msiexec /i VirtualBox-<version>-Win.msi ADDLOCAL=VBoxApplication,VBoxUSB

The user is able to choose between NDIS5 and NDIS6 host network filter drivers during the installation. This is done using a command line parameter, NETWORKTYPE. The NDIS6 driver is the default for most supported Windows hosts. For some legacy Windows versions, the installer will automatically select the NDIS5 driver and this cannot be changed.

You can force an install of the legacy NDIS5 host network filter driver by specifying NETWORKTYPE=NDIS5. For example, to install the NDIS5 driver on Windows 7 use either of the following commands:

VirtualBox.exe -msiparams NETWORKTYPE=NDIS5

msiexec /i VirtualBox-<version>-Win;.msi NETWORKTYPE=NDIS5

As Oracle VirtualBox uses the standard Microsoft Windows installer, Oracle VirtualBox can be safely uninstalled at any time. Click the program entry in the Add/Remove Programs list in the Windows Control Panel.

Unattended installations can be performed using the standard MSI support.

Public properties can be specified with the MSI API, to control additional behavior and features of the Windows host installer. Use either of the following commands:

VirtualBox.exe -msiparams NAME=VALUE [...]

msiexec /i VirtualBox-<version>-Win.msi NAME=VALUE [...]

The following public properties are available.

• VBOX_INSTALLDESKTOPSHORTCUT

  Specifies whether or not an Oracle VirtualBox icon on the desktop should be created.

  Set to 1 to enable, 0 to disable. Default is 1.

• VBOX_INSTALLQUICKLAUNCHSHORTCUT

  Specifies whether or not an Oracle VirtualBox icon in the Quick Launch Bar should be created.

  Set to 1 to enable, 0 to disable. Default is 1.

• VBOX_REGISTERFILEEXTENSIONS

  Specifies whether or not the file extensions .vbox, .vbox-extpack, .ovf, .ova, .vdi, .vmdk, .vhd and .vdd should be associated with Oracle VirtualBox. Files of these types then will be opened with Oracle VirtualBox.

  Set to 1 to enable, 0 to disable. Default is 1.

• VBOX_START

  Specifies whether to start Oracle VirtualBox right after successful installation.

  Set to 1 to enable, 0 to disable. Default is 1.

For macOS hosts, Oracle VirtualBox ships in a dmg disk image file. Perform the following steps to install on a macOS host:

1. Double-click the dmg file, to mount the contents.

2. A window opens, prompting you to double-click the VirtualBox.pkg installer file displayed in that window.

3. This starts the installer, which enables you to select where to install Oracle VirtualBox.

4. An Oracle VirtualBox icon is added to the Applications folder in the Finder.

To uninstall Oracle VirtualBox, open the disk image dmg file and double-click the uninstall icon shown.

To perform a noninteractive installation of Oracle VirtualBox you can use the command line version of the installer application.

Mount the dmg disk image file, as described in the installation procedure, or use the following command line:

hdiutil attach /path/to/VirtualBox-xyz.dmg

Open a terminal session and run the following command:

sudo installer -pkg /Volumes/VirtualBox/VirtualBox.pkg -target /Volumes/Macintosh\ HD

For the various versions of Linux that are supported as host operating systems, see Available Installation Packages.

You may need to install the following package on your Linux system before starting the installation. Some systems will do this for you automatically when you install Oracle VirtualBox.

• Qt 6.5.3 or later.

In order to run other operating systems in virtual machines alongside your main operating system, Oracle VirtualBox needs to integrate very tightly with your system. To do this it installs a driver module called vboxdrv into the system kernel. The kernel is the part of the operating system which controls your processor and physical hardware. Without this kernel module, you can still use VirtualBox Manager to configure virtual machines, but they will not start.

Network drivers called vboxnetflt and vboxnetadp are also installed. They enable virtual machines to make more use of your computer's network capabilities and are needed for any virtual machine networking beyond the basic NAT mode.

Since distributing driver modules separately from the kernel is not something which Linux supports well, the Oracle VirtualBox install process creates the modules on the system where they will be used. This means that you may need to install some software packages from the distribution which are needed for the build process. Required packages may include the following:

• GNU compiler (GCC)

• GNU Make (make)

• Kernel header files

Also ensure that all system updates have been installed and that your system is running the most up-to-date kernel for the distribution.

The following list includes some details of the required files for some common distributions. Start by finding the version name of your kernel, using the command uname -r in a terminal. The list assumes that you have not changed too much from the original installation, in particular that you have not installed a different kernel type.

• With Debian and Ubuntu-based distributions, you must install the correct version of the linux-headers, usually whichever of linux-headers-generic, linux-headers-amd64, linux-headers-i686 or linux-headers-i686-pae best matches the kernel version name. Also, the linux-kbuild package if it exists. Basic Ubuntu releases should have the correct packages installed by default.

• On Fedora, Red Hat, Oracle Linux and many other RPM-based systems, the kernel version sometimes has a code of letters or a word close to the end of the version name. For example "uek" for the Oracle Unbreakable Enterprise Kernel or "default" or "desktop" for the standard kernels. In this case, the package name is kernel-uek-devel or equivalent. If there is no such code, it is usually kernel-devel.

• On some SUSE and openSUSE Linux versions, you may need to install the kernel-source and kernel-syms packages.

If you suspect that something has gone wrong with module installation, check that your system is set up as described above and try running the following command, as root:

rcvboxdrv setup

Oracle VirtualBox is available in a number of package formats native to various common Linux distributions. See Available Installation Packages. In addition, there is an alternative generic installer (.run) which you can use on supported Linux distributions.

The Linux installers create the system user group vboxusers during installation. Any system user who is going to use USB devices from Oracle VirtualBox guests must be a member of that group. A user can be made a member of the group vboxusers either by using the desktop user and group tools, or with the following command:

sudo usermod -a -G vboxusers username

The easiest way to start an Oracle VirtualBox program is by running the program of your choice (VirtualBox, VBoxManage, or VBoxHeadless) from a terminal. These are symbolic links to VBox.sh that start the required program for you.

The following detailed instructions should only be of interest if you want to execute Oracle VirtualBox without installing it first. You should start by compiling the vboxdrv kernel module and inserting it into the Linux kernel. Oracle VirtualBox consists of a service daemon, VBoxSVC, and several application programs. The daemon is automatically started if necessary. All Oracle VirtualBox applications will communicate with the daemon through UNIX local domain sockets. There can be multiple daemon instances under different user accounts and applications can only communicate with the daemon running under the user account as the application. The local domain socket resides in a subdirectory of your system's directory for temporary files called .vbox-<username>-ipc. In case of communication problems or server startup problems, you may try to remove this directory.

All Oracle VirtualBox applications (VirtualBox, VBoxManage, and VBoxHeadless) require the Oracle VirtualBox directory to be in the library path, as follows:

LD_LIBRARY_PATH=. ./VBoxManage showvminfo "Windows XP"

Oracle VirtualBox is available as a standard Oracle Solaris package. Download the Oracle VirtualBox SunOS package, which includes the 64-bit version of Oracle VirtualBox. The installation must be performed as root and from the global zone. This is because the Oracle VirtualBox installer loads kernel drivers, which cannot be done from non-global zones. To verify which zone you are currently in, execute the zonename command.

To start installation, run the following commands:

gunzip -cd VirtualBox-version-number-SunOS.tar.gz | tar xvf -

The Oracle VirtualBox kernel package is integrated into the main package. Install the Oracle VirtualBox package as follows:

pkgadd -d VirtualBox-version-number-SunOS.pkg

The installer will then prompt you to enter the package you want to install. Choose 1 or all and proceed. Next the installer will ask you if you want to allow the postinstall script to be executed. Choose y and proceed, as it is essential to execute this script which installs the Oracle VirtualBox kernel module. Following this confirmation the installer will install Oracle VirtualBox and execute the postinstall setup script.

Once the postinstall script has been executed your installation is now complete. You may now safely delete the uncompressed package and autoresponse files from your system. Oracle VirtualBox is installed in /opt/VirtualBox.

The installer creates the system user group vboxuser during installation for Oracle Solaris hosts that support the USB features required by Oracle VirtualBox. Any system user who is going to use USB devices from Oracle VirtualBox guests must be a member of this group. A user can be made a member of this group either by using the desktop user and group tools or by running the following command as root:

usermod -G vboxuser username

Note that adding an active user to the vboxuser group will require the user to log out and then log in again. This should be done manually after successful installation of the package.

The easiest way to start an Oracle VirtualBox program is by running the program of your choice (VirtualBox, VBoxManage, or VBoxHeadless) from a terminal. These are symbolic links to VBox.sh that start the required program for you.

Alternatively, you can directly invoke the required programs from /opt/VirtualBox. Using the links provided is easier as you do not have to enter the full path.

You can configure some elements of the VirtualBox Qt GUI, such as fonts and colours, by running VBoxQtconfig from the terminal.

Uninstallation of Oracle VirtualBox on Oracle Solaris requires root permissions. To perform the uninstallation, start a root terminal session and run the following command:

pkgrm SUNWvbox

After confirmation, this will remove Oracle VirtualBox from your system.

To perform a noninteractive installation of Oracle VirtualBox there is a response file named autoresponse. The installer uses this for responses to inputs, rather than prompting the user.

Extract the tar.gz package as described in Performing the Installation. Then open a root terminal session and run the following command:

pkgadd -d VirtualBox-version-number-SunOS-x86 -n -a autoresponse SUNWvbox

To perform a noninteractive uninstallation, open a root terminal session and run the following command:

pkgrm -n -a /opt/VirtualBox/autoresponse SUNWvbox

After installing Oracle VirtualBox in the global zone (see Installing on Oracle Solaris Hosts for the installation instructions) the first step required to run Oracle VirtualBox in a non-global zone is to modify the zone's configuration to be able to access the Oracle VirtualBox device nodes located in the global zone. This is done by performing the following steps as a zone administrator in the global zone.

global$ zonecfg -z vboxzone
                  

Replace vboxzone with the name of the non-gloabl zone where you plan to run Oracle VirtualBox.

Use zonecfg(8) to add the device resource and the match property for each Oracle VirtualBox device node in the global zone to the non-global zone as follows:

zonecfg:vboxzone> add device
zonecfg:vboxzone:device> set match=/dev/vboxdrv
zonecfg:vboxzone:device> end
zonecfg:vboxzone> add device
zonecfg:vboxzone:device> set match=/dev/vboxdrvu
zonecfg:vboxzone:device> end
zonecfg:vboxzone> exit

On Oracle Solaris 11 if you plan to use VMs configured to use a USB device, e.g. a USB pointing device or a USB pass-through device, you should also pass through the /dev/vboxusbmon device using the steps above.

Oracle Solaris 11 does not support sparse root zones so you will need to loopback mount /opt/VirtualBox from the global zone into the non-global zone at the same path. This is done using zonecfg(8) to set the dir attribute and the special attribute for this directory. For example:

zonecfg:vboxzone> add fs
zonecfg:vboxzone:fs> set dir=/opt/VirtualBox
zonecfg:vboxzone:fs> set special=/opt/VirtualBox
zonecfg:vboxzone:fs> set type=lofs
zonecfg:vboxzone:fs> add options [readonly]
zonecfg:vboxzone:fs> end
zonecfg:vboxzone> exit

After making the above changes using zonecfg(8), reboot the zone using zoneadm(8) as follows:

global$ zoneadm -z vboxzone reboot
                  

for the changes to take effect. You will then be able to run Oracle VirtualBox from /opt/VirtualBox within the configured non-global zone.

Extension packs can be installed and managed using the Extension Pack Manager tool in VirtualBox Manager.

The Extension Pack Manager lists the extension packs that are currently installed on the host, and enables you to install and uninstall extension packs.

To display the Extension Pack Manager, go to the global Tools menu and click Extensions. The Extension Pack Manager is shown.

To install an extension pack using the Extension Pack Manager, click Install and select an extension package file. The extension pack is installed on the host and listed in Extension Pack Manager.

To uninstall an extension pack with the Extension Pack Manager, do the following:

1. Select the extension pack in the Extension Pack Manager window and click Uninstall.

2. Click Remove in the prompt dialog.

   The extension pack is uninstalled from the host and removed from the Extension Pack Manager.

Alternatively, you can use the VBoxManage command line to install and manage an Oracle VirtualBox Extension Pack. See VBoxManage extpack.

Oracle Premier Support covers the running of the following guest OSs in a VM with an x86 or x86-64 platform architecture, as appropriate.

Oracle Premier Support covers the running of the following guest OSs in a VM with an Arm64 platform architecture.

The following guest operating systems can be used with Oracle VirtualBox, but only qualify for limited support. Therefore, resolution of customer issues for such guest operating systems cannot be assured.

See also Host and Guest Combinations.

Oracle VirtualBox enables you to install and execute unmodified versions of macOS and OS X guests on supported host hardware. This feature is experimental and thus unsupported.

Be aware of the following important issues before you try to install a macOS guest:

• macOS is commercial, licensed software and contains both license and technical restrictions that limit its use to certain hardware and usage scenarios. You must understand and comply with these restrictions.

  In particular, Apple prohibits the installation of most versions of macOS on non-Apple hardware.

  These license restrictions are also enforced on a technical level. macOS verifies that it is running on Apple hardware. Most DVDs that accompany Apple hardware check for the exact model. These restrictions are not circumvented by Oracle VirtualBox and continue to apply.

• Only CPUs that are known and tested by Apple are supported. As a result, if your Intel CPU is newer than the macOS build, or if you have a non-Intel CPU, you will likely encounter a panic during bootup with an "Unsupported CPU" exception.

  Ensure that you use the macOS DVD that comes with your Apple hardware.

• The macOS installer expects the hard disk to be partitioned. So, the installer will not offer a partition selection to you. Before you can install the software successfully, start the Disk Utility from the Tools menu and partition the hard disk. Close the Disk Utility and proceed with the installation.

• macOS support in Oracle VirtualBox is an experimental feature. See Known Limitations.

If you use the Create VM wizard of VirtualBox Manager, Oracle VirtualBox automatically uses the correct settings for each selected 64-bit OS type. See Creating a Virtual Machine.

The following example shows how to perform an unattended guest installation for an Oracle Linux VM. The example uses various VBoxManage commands to prepare the guest VM. The VBoxManage unattended install command is then used to install and configure the guest OS.

1. Create the virtual machine.

   # VM="ol7-autoinstall"
   # VBoxManage list ostypes
   # VBoxManage createvm --name $VM --ostype "Oracle_64" --register

   Note the following:

   • The $VM variable represents the name of the VM.

   • The VBoxManage list ostypes command lists the guest OSes supported by Oracle VirtualBox, including the name used for each OS in the VBoxManage commands.

   • A 64-bit Oracle Linux 7 VM is created and registered with Oracle VirtualBox.

   • The VM has a unique UUID.

   • An XML settings file is generated.

2. Create a virtual hard disk and storage devices for the VM.

   # VBoxManage createhd --filename /VirtualBox/$VM/$VM.vdi --size 32768
   # VBoxManage storagectl $VM --name "SATA Controller" --add sata --controller IntelAHCI
   # VBoxManage storageattach $VM --storagectl "SATA Controller" --port 0 --device 0 \
   --type hdd --medium /VirtualBox/$VM/$VM.vdi
   # VBoxManage storagectl $VM --name "IDE Controller" --add ide
   # VBoxManage storageattach $VM --storagectl "IDE Controller" --port 0 --device 0 \
   --type dvddrive --medium /u01/Software/OL/OracleLinux-R7-U6-Server-x86_64-dvd.iso

   The previous commands do the following:

   • Create a 32768 MB virtual hard disk.

   • Create a SATA storage controller and attach the virtual hard disk.

   • Create an IDE storage controller for a virtual DVD drive and attach an Oracle Linux installation ISO.

3. (Optional) Configure some settings for the VM.

   # VBoxManage modifyvm $VM --ioapic on
   # VBoxManage modifyvm $VM --boot1 dvd --boot2 disk --boot3 none --boot4 none
   # VBoxManage modifyvm $VM --memory 8192 --vram 128

   The previous commands do the following:

   • Enable I/O APIC for the motherboard of the VM.

   • Configure the boot device order for the VM.

   • Allocate 8192 MB of RAM and 128 MB of video RAM to the VM.

4. Perform an unattended install of the OS.

   # VBoxManage unattended install $VM \
   --iso=/u01/Software/OL/OracleLinux-R7-U6-Server-x86_64-dvd.iso \
   --user=login --full-user-name=name --user-password password \
   --install-additions --time-zone=CET

   The previous command does the following:

   • Specifies an Oracle Linux ISO as the installation ISO.

   • Specifies a login name, full name, and login password for a default user on the guest OS.

     Note that the specified password is also used for the root user account on the guest.

   • Installs the Guest Additions on the VM.

   • Sets the time zone for the guest OS to Central European Time (CET).

5. Start the virtual machine.

   This step completes the unattended installation process.

   # VBoxManage startvm $VM --type headless

   The VM starts in headless mode, which means that the VirtualBox Manager window does not open.

In the Basic tab of the General settings category, you can find these settings:

• Name: The name of the the VM, as shown in the list of VMs in the main VirtualBox Manager window. Using this name, Oracle VirtualBox also saves the VM's configuration files. If you change the name, Oracle VirtualBox renames these files as well. As a result, you can only use characters which are allowed for file names on your host OS.

  Note that internally, Oracle VirtualBox uses unique identifiers (UUIDs) to identify virtual machines. You can display these using the VBoxManage commands.

• Type and Subtype: The type and subtype of the guest OS for the VM. For example, if the Type is Linux, the Subtype might be Oracle Linux.

  These are the same settings that are specified in the New Virtual Machine workflow. See Creating a Virtual Machine.

  Whereas the default settings of a newly created VM depend on the selected OS type, changing the type later has no effect on VM settings.

• Version: The version of the guest OS for the VM. This is the same setting that is specified in the New Virtual Machine workflow. See Creating a Virtual Machine.

The following settings are available in the Advanced tab:

• Snapshot Folder: By default, Oracle VirtualBox saves snapshot data together with your other Oracle VirtualBox configuration data. See Where Oracle VirtualBox Stores its Files. With this setting, you can specify any other folder for each VM.

• Shared Clipboard: You can select here whether the clipboard of the guest OS should be shared with that of your host. If you select Bidirectional, then Oracle VirtualBox will always make sure that both clipboards contain the same data. If you select Host to Guest or Guest to Host, then Oracle VirtualBox will only ever copy clipboard data in one direction.

  Clipboard sharing requires the Oracle VirtualBox Guest Additions.

  For security reasons, the shared clipboard is disabled by default. This setting can be changed at any time using the Shared Clipboard menu item in the Devices menu of the virtual machine.

• Drag and Drop: This setting enables support for drag and drop. Select an object, such as a file, from the host or guest and directly copy or open it on the guest or host. Multiple drag and drop modes for a VM enable restricting of access in either direction.

  For drag and drop to work, the Guest Additions need to be installed on the guest.

  Note:

  Drag and drop is disabled by default. This setting can be changed at any time using the Drag and Drop menu item in the Devices menu of the virtual machine.

  See Drag and Drop.

On the Description tab you can enter a description for your virtual machine. This has no effect on the functionality of the machine, but you may find this space useful to note down things such as the configuration of a virtual machine and the software that has been installed into it.

To insert a line break into the Description text field, press Shift+Enter.

The Disk Encryption tab enables you to encrypt disks that are attached to the virtual machine.

To enable disk encryption, select the Enable Disk Encryption check box.

Settings are available to configure the cipher used for encryption and the encryption password.

On the Motherboard tab, you can configure virtual hardware that would normally be on the motherboard of a real computer.

• Base Memory: Sets the amount of RAM that is allocated and given to the VM when it is running. The specified amount of memory will be requested from the host OS, so it must be available or made available as free memory on the host when attempting to start the VM and will not be available to the host while the VM is running. This is the same setting that was specified in the New Virtual Machine wizard, as described in Creating a Virtual Machine.

  Generally, it is possible to change the memory size after installing the guest OS. But you must not reduce the memory to an amount where the OS would no longer boot.

• Boot Order: Determines the order in which the guest OS will attempt to boot from the various virtual boot devices. Analogous to a real PC's BIOS setting, Oracle VirtualBox can tell a guest OS to start from the virtual floppy, the virtual CD/DVD drive, the virtual hard drive (each of these as defined by the other VM settings), the network, or none of these.

  If you select Network, the VM will attempt to boot from a network using the PXE mechanism. This needs to be configured in detail on the command line. See VBoxManage modifyvm.

• Chipset (Can't be changed on VMs with an Arm architecture): You can select which chipset will be presented to the virtual machine. PIIX3 is the default chipset for most guests. For some guest OSes such as Mac OS X, the PIIX3 chipset is not well supported. As a result, Oracle VirtualBox supports an emulation of the ICH9 chipset, which supports PCI express, three PCI buses, PCI-to-PCI bridges and Message Signaled Interrupts (MSI). This enables modern OSes to address more PCI devices and no longer requires IRQ sharing. Using the ICH9 chipset it is also possible to configure up to 36 network cards, compared to a maximum of eight network adapters with PIIX3. Note that ICH9 support is experimental and not recommended for guest OSes which do not require it.

• TPM (Can't be changed on VMs with an Arm architecture): Enables support for a Trusted Platform Module (TPM) security processor. Choose from the supported TPM versions.

• Pointing Device: The default virtual pointing device for some guest OSes is the traditional PS/2 mouse. If set to USB Tablet, Oracle VirtualBox reports to the virtual machine that a USB tablet device is present and communicates mouse events to the virtual machine through this device. Another setting is USB Multi-Touch Tablet, which is suitable for guests running Windows 8 or later.

  Using the virtual USB tablet has the advantage that movements are reported in absolute coordinates, instead of as relative position changes. This enables Oracle VirtualBox to translate mouse events over the VM window into tablet events without having to "capture" the mouse in the guest as described in Capturing and Releasing Keyboard and Mouse. This makes using the VM less tedious even if Guest Additions are not installed.

• Enable I/O APIC (Can't be changed on VMs with an Arm architecture): Advanced Programmable Interrupt Controllers (APICs) are an x86 hardware feature that have replaced Programmable Interrupt Controllers (PICs). With an I/O APIC, OSes can use more than 16 interrupt requests (IRQs) and therefore avoid IRQ sharing for improved reliability.

  Note:

  Enabling the I/O APIC is required, especially for 64-bit Windows guest OSes. It is also required if you want to use more than one virtual CPU in a virtual machine.

  However, software support for I/O APICs has been unreliable with some OSes other than Windows. Also, the use of an I/O APIC slightly increases the overhead of virtualization and therefore slows down the guest OS a little.

  Note:

  All Windows OSes install different kernels, depending on whether an I/O APIC is available. As with ACPI, the I/O APIC therefore must not be turned off after installation of a Windows guest OS. Turning it on after installation will have no effect however.

• Hardware Clock in UTC Time: If selected, Oracle VirtualBox will report the system time in UTC format to the guest instead of the local (host) time. This affects how the virtual real-time clock (RTC) operates and may be useful for UNIX-like guest OSes, which typically expect the hardware clock to be set to UTC.

• Enable EFI (Can't be changed on VMs with an Arm architecture): Enables Extensible Firmware Interface (EFI), which replaces the legacy BIOS and may be useful for certain advanced use cases. See Alternative Firmware (EFI).

• Enable Secure Boot: Enables Secure Boot, to provide a secure environment for starting the guest OS.

In addition, you can turn off the Advanced Configuration and Power Interface (ACPI) which Oracle VirtualBox presents to the guest OS by default.

ACPI is the current industry standard to allow OSes to recognize hardware, configure motherboards and other devices and manage power. As most computers contain this feature and Windows and Linux support ACPI, it is also enabled by default in Oracle VirtualBox. ACPI can only be turned off using the command line. See VBoxManage modifyvm.

On the Processor tab, you can configure settings for the CPU used by the virtual machine.

• Processor(s): Sets the number of virtual CPU cores the guest OSes can see. Oracle VirtualBox supports symmetrical multiprocessing (SMP) and can present up to 32 virtual CPU cores to each virtual machine.

  You should not configure virtual machines to use more CPU cores than are available physically. This includes real cores, with no hyperthreads.

• Execution Cap: Configures the CPU execution cap. This limits the amount of time a host CPU spends to emulate a virtual CPU. The default setting is 100%, meaning that there is no limitation. A setting of 50% implies a single virtual CPU can use up to 50% of a single host CPU. Note that limiting the execution time of the virtual CPUs may cause guest timing problems.

  A warning is displayed at the bottom of the Processor tab if an Execution Cap setting is made that may affect system performance.

• Enable PAE/NX (Can't be changed on VMs with an Arm architecture): Determines whether the PAE and NX capabilities of the host CPU will be exposed to the virtual machine.

  PAE stands for Physical Address Extension. Normally, if enabled and supported by the OS, then even a 32-bit x86 CPU can access more than 4 GB of RAM. This is made possible by adding another 4 bits to memory addresses, so that with 36 bits, up to 64 GB can be addressed. Some OSes, such as Ubuntu Server, require PAE support from the CPU and cannot be run in a virtual machine without it.

• Enable Nested VT-x/AMD-V (Can't be changed on VMs with an Arm architecture): Enables nested virtualization, with passthrough of hardware virtualization functions to the guest VM.

With virtual machines running modern server OSes, Oracle VirtualBox also supports CPU hot-plugging. For details, see CPU Hot-Plugging.

On this tab, you can configure Oracle VirtualBox to use hardware virtualization extensions that your host CPU supports.

• Paravirtualization Interface: Oracle VirtualBox provides paravirtualization interfaces to improve time-keeping accuracy and performance of guest OSes. The options available are documented under the --paravirt-provider option in VBoxManage modifyvm. For further details on the paravirtualization providers, see Paravirtualization Providers.

• Hardware Virtualization: You can configure hardware virtualization features for each virtual machine.

  • Enable Nested Paging: If the host CPU supports the nested paging (AMD-V) or EPT (Intel VT-x) features, then you can expect a significant performance increase by enabling nested paging in addition to hardware virtualization. For technical details, see Nested Paging and VPIDs. For Intel EPT security recommendations, see CVE-2018-3646.

  Advanced users may be interested in technical details about hardware virtualization. See Hardware Virtualization.

In most cases, the default settings on the Acceleration tab will work well. Oracle VirtualBox selects sensible defaults, depending on the OS that you selected when you created the virtual machine. In certain situations, however, you may want to change the preconfigured defaults.

• Video Memory: Sets the size of the memory provided by the virtual graphics card available to the guest, in megabytes. As with the main memory, the specified amount will be allocated from the host's resident memory. Based on the amount of video memory, higher resolutions and color depths may be available.

  VirtualBox Manager will show a warning if the amount of video memory is too small to be able to switch the VM into full screen mode. The minimum value depends on the number of virtual monitors, the screen resolution and the color depth of the host display as well as on the use of 3D acceleration. A rough estimate is (color depth / 8) x vertical pixels x horizontal pixels x number of screens = number of bytes. Extra memory may be required if display acceleration is used.

• Monitor Count: With this setting, Oracle VirtualBox can provide more than one virtual monitor to a virtual machine. If a guest OS supports multiple attached monitors, Oracle VirtualBox can pretend that multiple virtual monitors are present. Up to eight such virtual monitors are supported.

  The output of the multiple monitors are displayed on the host in multiple VM windows which are running side by side. However, in full screen and seamless mode, they use the available physical monitors attached to the host. As a result, for full screen and seamless modes to work with multiple monitors, you will need at least as many physical monitors as you have virtual monitors configured, or Oracle VirtualBox will report an error.

  You can configure the relationship between guest and host monitors using the View menu by pressing Host key + Home when you are in full screen or seamless mode.

  See also Known Limitations.

• Scale Factor: Enables scaling of the display size. For multiple monitor displays, you can set the scale factor for individual monitors, or globally for all of the monitors. Use the slider to select a scaling factor up to 200%.

  You can set a default scale factor for all VMs. Use the Display tab in the Preferences window.

• Graphics Controller: Specifies the graphics adapter type used by the guest VM. Note that you must install the Guest Additions on the guest VM to specify the VBoxSVGA or VMSVGA graphics controller. The following options are available:

  • VBoxSVGA: The default graphics controller for new VMs that use Windows 7 or later.

    This graphics controller improves performance and 3D support when compared to the legacy VBoxVGA option.

  • VBoxVGA: Use this graphics controller for legacy guest OSes. This is the default graphics controller for Windows versions before Windows 7 and for Oracle Solaris.

    3D acceleration is not supported for this graphics controller.

  • VMSVGA: Use this graphics controller to emulate a VMware SVGA graphics device. This is the default graphics controller for Linux guests.

  • None: Does not emulate a graphics adapter type.

• Enable 3D Acceleration: If a virtual machine has Guest Additions installed, you can select here whether the guest should support accelerated 3D graphics. See Hardware 3D Acceleration (OpenGL and Direct3D 8/9).

On the Remote Display tab, if the VirtualBox Remote Display Extension (VRDE) is installed, you can enable the VRDP server that is built into Oracle VirtualBox. This enables you to connect to the console of the virtual machine remotely with any standard RDP viewer, such as mstsc.exe that comes with Microsoft Windows. On Linux and Oracle Solaris systems you can use the standard open source rdesktop program. These features are described in Remote Display (VRDP Support).

• Enable Server: Select this check box and configure settings for the remote display connection.

On the Recording tab you can enable video and audio recording for a virtual machine and change related settings. Note that these features can be enabled and disabled while a VM is running. Settings apply to all selected screens.

• Enable Recording: Select this check box and select a Recording Mode option.

• Recording Mode: You can choose to record video, audio, or both video and audio.

  Some settings on the Recording tab may be grayed out, depending on the Recording Mode setting.

• File Path: The file where the recording is saved.

• Frame Size: The video resolution of the recorded video, in pixels. The drop-down list enables you to select from common frame sizes.

• Frame Rate: Use the slider to set the maximum number of video frames per second (FPS) to record. Frames that have a higher frequency are skipped. Increasing this value reduces the number of skipped frames and increases the file size.

• Video Quality: Use the slider to set the bit rate of the video in kilobits per second. Increasing this value improves the appearance of the video at the cost of an increased file size.

• Audio Quality: Use the slider to set the quality of the audio recording. Increasing this value improves the audio quality at the cost of an increased file size.

• Screens: For a multiple monitor display, you can select which screens to record video from.

As you adjust the video and audio recording settings, the approximate output file size for a five minute video is shown.

The USB section in a virtual machine's Settings window enables you to configure Oracle VirtualBox's sophisticated USB support.

Oracle VirtualBox can enable virtual machines to access the USB devices on your host directly. To achieve this, Oracle VirtualBox presents the guest OS with a virtual USB controller.

Oracle VirtualBox also enables your guests to connect to remote USB devices by use of the VirtualBox Remote Desktop Extension (VRDE). See Remote USB.

1. Ensure the VM is not running.
2. Select the VM in the machine list, and then click Settings.
3. On the USB tab, select Enable USB Controller and choose the USB Controller you need for your guest OS. In most cases this will be xHCI. Only use OHCI or EHCI if your guest OS does not support xHCI. For some legacy Windows guests you'll need to install third party drivers for xHCI support.
   • OHCI supports USB 1.1
   • EHCI supports USB 2.0. This also enables OHCI.
   • xHCI supports all USB speeds up to USB 3.0
4. Specify which devices can be attached to the guest by adding USB Device Filters. USB devices with a matching filter will be automatically passed to the guest once they are attached to the host. USB devices without a matching filter can be passed manually to the guest, for example by using the Devices, USB menu.
   • Click the USB filter button to create a new filter with blank fields, and then complete the fields.
   • Or, click the Add USB filter button to create a filter with the fields completed for the selected USB device.

   Give the filter a name, for later reference, and specify the filter criteria. The more criteria you specify, the more precisely devices will be selected. For instance, if you specify only a vendor ID of 046d, all devices produced by Logitech will be available to the guest. If you fill in all fields, on the other hand, the filter will only apply to a particular device model from a particular vendor, and not even to other devices of the same type with a different revision and serial number.

   The following criteria are available:

   • Vendor and Product ID. With USB, each vendor of USB products carries an identification number that is unique world-wide, called the vendor ID. Similarly, each line of products is assigned a product ID number. Both numbers are commonly written in hexadecimal, and a colon separates the vendor from the product ID. For example, 046d:c016 stands for Logitech as a vendor, and the M-UV69a Optical Wheel Mouse product.

     Alternatively, you can also specify Manufacturer and Product by name.

     To list all the USB devices that are connected to your host machine with their respective vendor IDs and product IDs, use the following command:

     VBoxManage list usbhost

     On Windows, you can also see all USB devices that are attached to your system in the Device Manager. On Linux, you can use the lsusb command.

   • Serial Number. While vendor ID and product ID are quite specific to identify USB devices, if you have two identical devices of the same brand and product line, you will also need their serial numbers to filter them out correctly.

   • Remote. This setting specifies whether the device will be local only, remote only, such as over VRDP, or either.

   As an example, you could create a new USB filter and specify a vendor ID of 046d for Logitech, Inc, a manufacturer index of 1, and not remote. Then any USB devices on the host system produced by Logitech, Inc with a manufacturer index of 1 will be visible to the guest system.

   Several filters can select a single device. For example, a filter which selects all Logitech devices, and one which selects a particular webcam.

5. On a Windows host, you will need to unplug and reconnect a USB device to use it after creating a filter for it.

6. Ensure the filters you need immediately are selected in the list. Selected filters will be attached automatically when the VM starts.

On Windows hosts, a kernel mode device driver provides USB proxy support. It implements both a USB monitor, which enables Oracle VirtualBox to capture devices when they are plugged in, and a USB device driver to claim USB devices for a particular virtual machine. System reboots are not necessary after installing the driver. Also, you do not need to replug devices for Oracle VirtualBox to claim them.

On supported Linux hosts, Oracle VirtualBox accesses USB devices through special files in the file system. When Oracle VirtualBox is installed, these are made available to all users in the vboxusers system group. In order to be able to access USB from guest systems, make sure that you are a member of this group.

EFI provides two distinct video interfaces: GOP (Graphics Output Protocol) and UGA (Universal Graphics Adapter). Modern OSes, such as Mac OS X, generally use GOP, while some older ones still use UGA. Oracle VirtualBox provides a configuration option to control the graphics resolution for both interfaces, making the difference mostly irrelevant for users.

The default resolution is 1024x768. To select a graphics resolution for EFI, use the following VBoxManage command:

VBoxManage setextradata "VM name" VBoxInternal2/EfiGraphicsResolution HxV

Determine the horizontal resolution H and the vertical resolution V from the following list of default resolutions:

VGA

640x480, 32bpp, 4:3

SVGA

800x600, 32bpp, 4:3

XGA

1024x768, 32bpp, 4:3

XGA+

1152x864, 32bpp, 4:3

HD

1280x720, 32bpp, 16:9

WXGA

1280x800, 32bpp, 16:10

SXGA

1280x1024, 32bpp, 5:4

SXGA+

1400x1050, 32bpp, 4:3

WXGA+

1440x900, 32bpp, 16:10

HD+

1600x900, 32bpp, 16:9

UXGA

1600x1200, 32bpp, 4:3

WSXGA+

1680x1050, 32bpp, 16:10

Full HD

1920x1080, 32bpp, 16:9

WUXGA

1920x1200, 32bpp, 16:10

DCI 2K

2048x1080, 32bpp, 19:10

Full HD+

2160x1440, 32bpp, 3:2

Unnamed

2304x1440, 32bpp, 16:10

QHD

2560x1440, 32bpp, 16:9

WQXGA

2560x1600, 32bpp, 16:10

QWXGA+

2880x1800, 32bpp, 16:10

QHD+

3200x1800, 32bpp, 16:9

WQSXGA

3200x2048, 32bpp, 16:10

4K UHD

3840x2160, 32bpp, 16:9

WQUXGA

3840x2400, 32bpp, 16:10

DCI 4K

4096x2160, 32bpp, 19:10

HXGA

4096x3072, 32bpp, 4:3

UHD+

5120x2880, 32bpp, 16:9

WHXGA

5120x3200, 32bpp, 16:10

WHSXGA

6400x4096, 32bpp, 16:10

HUXGA

6400x4800, 32bpp, 4:3

8K UHD2

7680x4320, 32bpp, 16:9

If this list of default resolution does not cover your needs, see Custom VESA Resolutions. Note that the color depth value specified in a custom video mode must be specified. Color depths of 8, 16, 24, and 32 are accepted. EFI assumes a color depth of 32 by default.

The EFI default video resolution settings can only be changed when the VM is powered off.

It is currently not possible to manipulate EFI variables from within a running guest. For example, setting the boot-args variable by running the nvram tool in a Mac OS X guest will not work. As an alternative method, VBoxInternal2/EfiBootArgs extradata can be passed to a VM in order to set the boot-args variable. To change the boot-args EFI variable, use the following command:

VBoxManage setextradata "VM name" VBoxInternal2/EfiBootArgs <value>

The Oracle VirtualBox Windows Guest Additions are designed to be installed in a virtual machine running a Windows operating system. The following versions of Windows guests are supported:

• Microsoft Windows 11

• Microsoft Windows Server 2022

• Microsoft Windows 10 (all builds)

• Microsoft Windows Server 2019

• Microsoft Windows Server 2016

• Microsoft Windows 8.1 (all editions)

• Microsoft Windows Server 2012R2

• Microsoft Windows 8 (all editions)

• Microsoft Windows Server 2012

• Microsoft Windows 7 (all editions)

• Microsoft Windows Server 2008R2

• Microsoft Windows Vista (all editions)

• Microsoft Windows Server 2008

• Microsoft Windows XP (any service pack)

• Microsoft Windows Server 2003 (any service pack)

• Microsoft Windows 2000 (any service pack)

• Microsoft Windows NT 4.0 (any service pack)

Like the Windows Guest Additions, the Oracle VirtualBox Guest Additions for Linux are a set of device drivers and system applications which may be installed in the guest operating system.

The following Linux distributions are officially supported:

• Oracle Linux as of version 5, including UEK kernels

• Fedora as of Fedora Core 4

• Red Hat Enterprise Linux as of version 3

• SUSE and openSUSE Linux as of version 9

• Ubuntu as of version 5.10

Many other distributions are known to work with the Guest Additions.

The version of the Linux kernel supplied by default in SUSE and openSUSE 10.2, Ubuntu 6.10 (all versions) and Ubuntu 6.06 (server edition) contains a bug which can cause it to crash during startup when it is run in a virtual machine. The Guest Additions work in those distributions.

Note that some Linux distributions already come with all or part of the Oracle VirtualBox Guest Additions. You may choose to keep the distribution's version of the Guest Additions but these are often out of date and limited in functionality, so we recommend replacing them with the Guest Additions that come with Oracle VirtualBox. The Oracle VirtualBox Linux Guest Additions installer tries to detect an existing installation and replace them but depending on how the distribution integrates the Guest Additions, this may require some manual interaction. It is highly recommended to take a snapshot of the virtual machine before replacing preinstalled Guest Additions.

Like the Windows Guest Additions, the Oracle VirtualBox Guest Additions for Oracle Solaris take the form of a set of device drivers and system applications which may be installed in the guest operating system.

The following Oracle Solaris distributions are officially supported:

• Oracle Solaris 11, including Oracle Solaris 11 Express

• Oracle Solaris 10 4/08 and later

Other distributions may work if they are based on comparable software releases.

Oracle VirtualBox also ships with a set of drivers that improve running OS/2 in a virtual machine. Due to restrictions of OS/2 itself, this variant of the Guest Additions has a limited feature set. See Known Limitations for details.

The OS/2 Guest Additions are provided on the same ISO CD-ROM as those for the other platforms. Mount the ISO in OS/2 as described previously. The OS/2 Guest Additions are located in the directory \OS2.

We do not provide an automatic installer at this time. See the readme.txt file in the CD-ROM directory, which describes how to install the OS/2 Guest Additions manually.

You can mount the shared folder from inside a VM, in the same way as you would mount an ordinary network share:

• In a Windows guest, shared folders are browseable and therefore visible in Windows Explorer. To attach the host's shared folder to your Windows guest, open Windows Explorer and look for the folder in My Networking Places, Entire Network, Oracle VirtualBox Shared Folders. By right-clicking on a shared folder and selecting Map Network Drive from the menu that pops up, you can assign a drive letter to that shared folder.

  Alternatively, on the Windows command line, use the following command:

  net use x: \\vboxsvr\sharename

  While vboxsvr is a fixed name, note that vboxsrv would also work, replace x: with the drive letter that you want to use for the share, and sharename with the share name specified with VBoxManage.

• In a Linux guest, use the following command:

  mount -t vboxsf [-o OPTIONS] sharename mountpoint

  To mount a shared folder during boot, add the following entry to /etc/fstab:

  sharename   mountpoint   vboxsf   defaults  0   0

• In a Oracle Solaris guest, use the following command:

  mount -F vboxfs [-o OPTIONS] sharename mountpoint

  Replace sharename, use a lowercase string, with the share name specified with VBoxManage or VirtualBox Manager. Replace mountpoint with the path where you want the share to be mounted on the guest, such as /mnt/share. The usual mount rules apply. For example, create this directory first if it does not exist yet.

  Here is an example of mounting the shared folder for the user jack on Oracle Solaris:

  $ id
  uid=5000(jack) gid=1(other)
  $ mkdir /export/home/jack/mount
  $ pfexec mount -F vboxfs -o uid=5000,gid=1 jackshare /export/home/jack/mount
  $ cd ~/mount
  $ ls
  sharedfile1.mp3 sharedfile2.txt
  $

  Beyond the standard options supplied by the mount command, the following are available:

  iocharset CHARSET

  This option sets the character set used for I/O operations. Note that on Linux guests, if the iocharset option is not specified, then the Guest Additions driver will attempt to use the character set specified by the CONFIG_NLS_DEFAULT kernel option. If this option is not set either, then UTF-8 is used.

  convertcp CHARSET

  This option specifies the character set used for the shared folder name. This is UTF-8 by default.

  The generic mount options, documented in the mount manual page, apply also. Especially useful are the options uid, gid and mode, as they can allow access by normal users in read/write mode, depending on the settings, even if root has mounted the filesystem.

• In an OS/2 guest, use the VBoxControl command to manage shared folders. For example:

  VBoxControl sharedfolder use D: MyShareName
  VBoxControl sharedfolder unuse D:
  VBoxControl sharedfolder list

  As with Windows guests, shared folders can also be accessed using UNC , with \\VBoxSF\, \\VBoxSvr\ or \\VBoxSrv\ as the server name and the shared folder name as sharename.

Oracle VirtualBox provides the option to mount shared folders automatically. When automatic mounting is enabled for a shared folder, the Guest Additions service will mount it for you automatically. For Windows or OS/2, a preferred drive letter can also be specified. For Linux or Oracle Solaris, a mount point directory can also be specified.

If a drive letter or mount point is not specified, or is in use already, an alternative location is found by the Guest Additions service. The service searches for an alternative location depending on the guest OS, as follows:

• Windows and OS/2 guests. Search for a free drive letter, starting at Z:. If all drive letters are assigned, the folder is not mounted.

• Linux and Oracle Solaris guests. Folders are mounted under the /media directory. The folder name is normalized (no spaces, slashes or colons) and is prefixed with sf_.

  For example, if you have a shared folder called myfiles, it will appear as /media/sf_myfiles in the guest.

  The guest properties /VirtualBox/GuestAdd/SharedFolders/MountDir and the more generic /VirtualBox/GuestAdd/SharedFolders/MountPrefix can be used to override the automatic mount directory and prefix. See Guest Properties.

Access to an automatically mounted shared folder is granted to everyone in a Windows guest, including the guest user. For Linux and Oracle Solaris guests, access is restricted to members of the group vboxsf and the root user.

The following limitations are known for Shared Clipboard file transfers:

On Linux hosts and guests, Shared Clipboard file transfers are limited to files only, one file per transfer. Transferring symbolic links is not supported.

Shared Clipboard file transfers are only tested and supported with the official default file managers of the guest or host operating system unless mentioned otherwise.

As Oracle VirtualBox can run on a variety of host operating systems and also supports a wide range of guests, certain data formats must be translated after transfer. This is so that the destination operating system, which receives the data, is able to handle them in an appropriate manner.

The following formats are handled by the Oracle VirtualBox drag and drop service:

• Plain text: From applications such as text editors, internet browsers and terminal windows.

• Files: From file managers such as Windows Explorer, Nautilus, and Finder.

• Directories: For directories, the same formats apply as for files.

The following limitations are known for drag and drop:

On Windows hosts, dragging and dropping content between UAC-elevated (User Account Control) programs and non-UAC-elevated programs is not allowed. If you start Oracle VirtualBox with Administrator privileges then drag and drop will not work with Windows Explorer, which runs with regular user privileges by default.

On Linux hosts and guests, programs can query for drag and drop data while the drag operation is still in progress. For example, on LXDE using the PCManFM file manager. This currently is not supported. As a workaround, a different file manager, such as Nautilus, can be used instead.

The Oracle VirtualBox Guest Additions contain experimental hardware 3D support for Windows, Linux, and Oracle Solaris guests.

With this feature, if an application inside your virtual machine uses 3D features through the OpenGL or Direct3D 8/9 programming interfaces, instead of emulating them in software, which would be slow, Oracle VirtualBox will attempt to use your host's 3D hardware. This works for all supported host platforms, provided that your host operating system can make use of your accelerated 3D hardware in the first place.

The 3D acceleration feature currently has the following preconditions:

• It is only available for certain Windows, Linux, and Oracle Solaris guests. In particular:

  • 3D acceleration with Windows guests requires Windows 2000 or later. Apart from on Windows 2000 guests, both OpenGL and Direct3D 8/9 are supported on an experimental basis.

  • OpenGL on Linux requires kernel 2.6.27 or later, as well as X.org server version 1.5 or later. Ubuntu 10.10 and Fedora 14 have been tested and confirmed as working.

  • OpenGL on Oracle Solaris guests requires X.org server version 1.5 or later.

• The Guest Additions must be installed.

  Note:

  For the basic Direct3D acceleration to work in a Windows Guest, Oracle VirtualBox needs to replace Windows system files in the virtual machine. As a result, the Guest Additions installation program offers Direct3D acceleration as an option that must be explicitly enabled. Also, you must install the Guest Additions in Safe Mode. This does not apply to the WDDM Direct3D video driver available for Windows Vista and later. See Known Limitations for details.

• Because 3D support is still experimental at this time, it is disabled by default and must be manually enabled in the VM settings. See Display Settings.

  Note:

  Untrusted guest systems should not be allowed to use the 3D acceleration features of Oracle VirtualBox, just as untrusted host software should not be allowed to use 3D acceleration. Drivers for 3D hardware are generally too complex to be made properly secure and any software which is allowed to access them may be able to compromise the operating system running them. In addition, enabling 3D acceleration gives the guest direct access to a large body of additional program code in the Oracle VirtualBox host process which it might conceivably be able to use to crash the virtual machine.

To enable Aero theme support, the Oracle VirtualBox WDDM video driver must be installed, which is available with the Guest Additions installation. The WDDM driver is not installed by default for Vista and Windows 7 guests and must be manually selected in the Guest Additions installer by clicking No in the Would You Like to Install Basic Direct3D Support dialog displayed when the Direct3D feature is selected.

The Aero theme is not enabled by default on Windows. See your Windows platform documentation for details of how to enable the Aero theme.

Technically, Oracle VirtualBox implements 3D acceleration by installing an additional hardware 3D driver inside the guest when the Guest Additions are installed. This driver acts as a hardware 3D driver and reports to the guest operating system that the virtual hardware is capable of 3D hardware acceleration. When an application in the guest then requests hardware acceleration through the OpenGL or Direct3D programming interfaces, these are sent to the host through a special communication tunnel implemented by Oracle VirtualBox. The host then performs the requested 3D operation using the host's programming interfaces.

The properties /VirtualBox/HostInfo/VBoxVer, /VirtualBox/HostInfo/VBoxVerExt or /VirtualBox/HostInfo/VBoxRev can be waited on to detect that the VM state was restored from saved state or snapshot:

$ VBoxControl guestproperty wait /VirtualBox/HostInfo/VBoxVer

Similarly the /VirtualBox/HostInfo/ResumeCounter can be used to detect that a VM was resumed from the paused state or saved state.

To use the Guest Control File Manager to transfer files, follow these steps.

1. Ensure you have the username and password for an account on the guest system, with appropriate permissions on the files you need to access.

2. Open the Guest Control File Manager. Do either of the following:

   • In the guest VM, select Machine, File Manager.

   • In VirtualBox Manager, click the machine name. Click File Manager in the machine tools menu for the VM.

   The Host File System pane shows the files on the host system.

3. In the Guest File System pane, enter the User Name and Password for the user you want to log in as.

   Click Open Session.

   The VM file system appears in the Guest File System pane.

4. To transfer from the VM to the host, select the file(s) and click Copy From Guest to Host.

   To transfer from the host to the VM, select the file(s) and click Copy From Host to Guest.

5. Check the progress of the transfer in the Operations pane.

6. Click Close to end the guest session and the Guest Control File Manager.

The Guest Additions can change the amount of host memory that a VM uses, while the machine is running. Because of how this is implemented, this feature is called memory ballooning.

Normally, to change the amount of memory allocated to a virtual machine, you have to shut down the virtual machine entirely and modify its settings. With memory ballooning, memory that was allocated for a virtual machine can be given to another virtual machine without having to shut the machine down.

When memory ballooning is requested, the Oracle VirtualBox Guest Additions, which run inside the guest, allocate physical memory from the guest operating system on the kernel level and lock this memory down in the guest. This ensures that the guest will not use that memory any longer. No guest applications can allocate it, and the guest kernel will not use it either. Oracle VirtualBox can then reuse this memory and give it to another virtual machine.

The memory made available through the ballooning mechanism is only available for reuse by Oracle VirtualBox. It is not returned as free memory to the host. Requesting balloon memory from a running guest will therefore not increase the amount of free, unallocated memory on the host. Effectively, memory ballooning is therefore a memory overcommitment mechanism for multiple virtual machines while they are running. This can be useful to temporarily start another machine, or in more complicated environments, for sophisticated memory management of many virtual machines that may be running in parallel depending on how memory is used by the guests.

At this time, memory ballooning is only supported through VBoxManage. Use the following command to increase or decrease the size of the memory balloon within a running virtual machine that has Guest Additions installed:

VBoxManage controlvm "VM name" guestmemoryballoon n

where VM name is the name or UUID of the virtual machine in question and n is the amount of memory to allocate from the guest in megabytes. See VBoxManage controlvm.

You can also set a default balloon that will automatically be requested from the VM every time after it has started up with the following command:

VBoxManage modifyvm "VM name" --guest-memory-balloon n

By default, no balloon memory is allocated. This is a VM setting, like other modifyvm settings, and therefore can only be set while the machine is shut down. See VBoxManage modifyvm.

Whereas memory ballooning simply reduces the amount of RAM that is available to a VM, Page Fusion works differently. It avoids memory duplication between several similar running VMs.

In a server environment running several similar VMs on the same host, lots of memory pages are identical. For example, if the VMs are using identical operating systems. Oracle VirtualBox's Page Fusion technology can efficiently identify these identical memory pages and share them between multiple VMs.

The more similar the VMs on a given host are, the more efficiently Page Fusion can reduce the amount of host memory that is in use. It therefore works best if all VMs on a host run identical operating systems. Instead of having a complete copy of each operating system in each VM, Page Fusion identifies the identical memory pages in use by these operating systems and eliminates the duplicates, sharing host memory between several machines. This is called deduplication. If a VM tries to modify a page that has been shared with other VMs, a new page is allocated again for that VM with a copy of the shared page. This is called copy on write. All this is fully transparent to the virtual machine.

You may be familiar with this kind of memory overcommitment from other hypervisor products, which call this feature page sharing or same page merging. However, Page Fusion differs significantly from those other solutions, whose approaches have several drawbacks:

• Traditional hypervisors scan all guest memory and compute checksums, also called hashes, for every single memory page. Then, they look for pages with identical hashes and compare the entire content of those pages. If two pages produce the same hash, it is very likely that the pages are identical in content. This process can take rather long, especially if the system is not idling. As a result, the additional memory only becomes available after a significant amount of time, such as hours or sometimes days. Even worse, this kind of page sharing algorithm generally consumes significant CPU resources and increases the virtualization overhead by 10 to 20%.

  Page Fusion in Oracle VirtualBox uses logic in the Oracle VirtualBox Guest Additions to quickly identify memory cells that are most likely identical across VMs. It can therefore achieve most of the possible savings of page sharing almost immediately and with almost no overhead.

• Page Fusion is also much less likely to be confused by identical memory that it will eliminate, just to learn seconds later that the memory will now change and having to perform a highly expensive and often service-disrupting reallocation.

At this time, Page Fusion can only be controlled with VBoxManage, and only while a VM is shut down. To enable Page Fusion for a VM, use the following command:

VBoxManage modifyvm "VM name" --page-fusion on

You can observe Page Fusion operation using some metrics. RAM/VMM/Shared shows the total amount of fused pages, whereas the per-VM metric Guest/RAM/Usage/Shared will return the amount of fused memory for a given VM. See VBoxManage metrics for information on how to query metrics.

The Guest Additions provide services for controlling the guest system's monitor topology. Monitor topology means the resolution of each virtual monitor and its state (disabled/enabled). The resolution of a virtual monitor can be modified from the host side either by resizing the window that hosts the virtual monitor, by using the View menu or the VBoxManage controlvm vmname setscreenlayout command. On guest operating systems with X11/Wayland desktops this is put into effect by either of the following two services:

        VBoxClient --vmsvga
        VBoxDRMClient
      

The following are some details about guest screen resolution control functionality:

• On X11/Wayland desktops the resizing service is started during desktop session initialization, that is desktop login. On X11 desktops VBoxClient --vmsvga handles screen topology through the RandR extension. On Wayland clients VBoxDRMClient is used. The decision is made automatically at each desktop session start.

• On 32-bit guest operating systems VBoxDRMClient is always used, in order to work around bugs.

• Since the monitor topology control services are initialized during the desktop session start, it is impossible to control the monitor resolution of display managers such as GDM or LightDM. This default behavior can be changed by setting the guest property /VirtualBox/GuestAdd/DRMResize of the virtual machine to any value. See Guest Properties for details of how to update guest properties. When this guest property is set then VBoxDRMClient is started during the guest OS boot and stays active all the time, for both the display manager login screen and the desktop session.

1. Display the Hard Disks tab in Virtual Media Manager and click Create.

2. Select a file type for the new virtual hard disk image.

3. Select dynamically allocated or fixed size storage for the virtual hard disk.

4. Configure the location of the virtual hard disk file and use the slider to set the size limit for the virtual hard disk.

   Click Finish to create the virtual hard disk file.

   The virtual hard disk image is created in the specified location and added to the Hard Disks tab in Virtual Media Manager.

Use the VISO Creator tool to create a virtual optical disk image. This enables you to create a virtual ISO from selected files on the host.

1. Display the Optical Disks tab in Virtual Media Manager and click Create.

   The VISO Creator tool is shown.

2. Create the virtual ISO file.

   1. Configure the name of the ISO file.

      Click Settings and select the VISO Options tab. Enter the name in the Viso Name field.

   2. Add files to your virtual ISO.

      In the Host File System pane, select files to copy from the host system to the virtual ISO.

      Click Add Items To VISO. The files are displayed in the VISO Content pane.

      The following file operations are also available:

      • To create folders on the virtual ISO, click Create New Directory.

      • To remove files from the virtual ISO, select files in the VISO Content pane and click Remove Items From VISO.

      • To remove all files from the virtual ISO, click Reset the VISO Content.

      • To import all file content from an existing ISO into the virtual ISO, highlight the ISO file name and click Import Selected ISO into the VISO Content. The imported ISO is opened and content is listed in the VISO Content pane.

        To remove files from the imported ISO, select the files in the Viso Content pane and click Remove Selected Item(s) from VISO.

3. Create the virtual ISO image.

   Click Save and Close.

   A virtual ISO file with the specified name and content is created.

Use the Floppy Disk Creator tool to create a floppy disk image.

1. Display the Floppy Disks tab in Virtual Media Manager and click Create.

   The Floppy Disk Creator tool is shown.

2. Configure the following settings:

   • File Path: The name and location of the floppy disk image.

   • Size: Select from the list of supported floppy disk sizes.

   • Format Disk as FAT 12: This is the default format used for most floppy disks. For an unformatted disk, do not select this option.

3. Create the floppy disk image file.

   Click Create.

   The floppy disk image is created in the specified location and added to the Floppy Disks tab in Virtual Media Manager.

The following examples show how to use the vboximg-mount command to view information about virtual disk images.

The following command outputs detailed information about all registered VMs and associated snapshots:

$ vboximg-mount --list --verbose

    ------------------------------------------------------
    VM Name:   "macOS High Sierra 10.13"
    UUID:      3887d96d-831c-4187-a55a-567c504ff0e1
    Location:  /Volumes/work/vm_guests/macOS High Sierra 10.13/macOS High Sierra 10.13.vbox
       -----------------------
       HDD base:   "macOS High Sierra 10.13.vdi"
       UUID:       f9ea7173-6869-4aa9-b487-68023a655980
       Location:   /Volumes/work/vm_guests/macOS High Sierra 10.13/macOS High Sierra 10.13.vdi

         Diff 1:
              UUID:       98c2bac9-cf37-443d-a935-4e879b70166d
              Location:   /Volumes/work/vm_guests/macOS High Sierra 10.13/
              Snapshots/{98c2bac9-cf37-443d-a935-4e879b70166d}.vdi
         Diff 2:
              UUID:       f401f381-7377-40b3-948e-3c61241b1a42
              Location:   /Volumes/work/vm_guests/macOS High Sierra 10.13/
              Snapshots/{f401f381-7377-40b3-948e-3c61241b1a42}.vdi
       -----------------------
       HDD base:   "simple_fixed_disk.vdi"
       UUID:       ffba4d7e-1277-489d-8173-22ca7660773d
       Location:   /Volumes/work/vm_guests/macOS High Sierra 10.13/simple_fixed_disk.vdi

         Diff 1:
              UUID:       aecab681-0d2d-468b-8682-93f79dc97a48
              Location:   /Volumes/work/vm_guests/macOS High Sierra 10.13/
              Snapshots/{aecab681-0d2d-468b-8682-93f79dc97a48}.vdi
         Diff 2:
              UUID:       70d6b34d-8422-47fa-8521-3b6929a1971c
              Location:   /Volumes/work/vm_guests/macOS High Sierra 10.13/
              Snapshots/{70d6b34d-8422-47fa-8521-3b6929a1971c}.vdi
      ------------------------------------------------------
      VM Name:   "debian"
      UUID:      5365ab5f-470d-44c0-9863-dad532ee5905
      Location:  /Volumes/work/vm_guests/debian/debian.vbox
         -----------------------
         HDD base:   "debian.vdi"
         UUID:       96d2e92e-0d4e-46ab-a0f1-008fdbf997e7
         Location:   /Volumes/work/vm_guests/debian/ol7.vdi

            Diff 1:
                UUID:       f9cc866a-9166-42e9-a503-bbfe9b7312e8
                Location:   /Volumes/work/vm_guests/debian/Snapshots/
                {f9cc866a-9166-42e9-a503-bbfe9b7312e8}.vdi

The following command outputs partition information about the specified disk image:

$ vboximg-mount --image=f9ea7173-6869-4aa9-b487-68023a655980 --list

    Virtual disk image:

       Path: /Volumes/work/vm_guests/macOS High Sierra 10.13/macOS High Sierra 10.13.vdi
       UUID: f9ea7173-6869-4aa9-b487-68023a655980

      #     Start  Sectors     Size       Offset  Type
      1        40  409599    199.9M        20480  EFI System
      2    409640  67453071   32.1G    209735680  Hierarchical File System Plus (HFS+)
      3  67862712  1269535   107.8M  34745708544  Apple Boot (Recovery HD)

The following steps show how to use the vboximg-mount command to mount a partition of a virtual disk image on the host OS.

1. Create a mount point on the host OS. For example:

   $ mkdir macos_sysdisk

2. Show partition information about the virtual disk image.

   $ vboximg-mount --image=uuid --list

   where uuid is the UUID of the disk image.

3. Use vboximg-mount to perform a FUSE mount of a partition on the virtual disk image. For example:

   $ vboximg-mount --image=uuid -p 2 macos_sysdisk

   where uuid is the UUID for the disk image.

   In this example, partition 2 is mounted on the macos_sysdisk mount point. The mount includes all snapshots for the disk image.

4. Use the host OS to mount the vhdd device node. The FUSE-mounted device node represents the virtual disk image.

   $ ls macos_sysdisk
      macOS High Sierra 10.13.vdi  vhdd
   $ sudo mount macos_sysdisk/vhdd /mnt

As the virtual machine is connected to a private network internal to Oracle VirtualBox and invisible to the host, network services on the guest are not accessible to the host machine or to other computers on the same network. However, like a physical router, Oracle VirtualBox can make selected services available to the world outside the guest through port forwarding. This means that Oracle VirtualBox listens to certain ports on the host and resends all packets which arrive there to the guest, on the same or a different port.

To an application on the host or other physical or virtual machines on the network, it looks as though the service being proxied is actually running on the host. This also means that you cannot run the same service on the same ports on the host. However, you still gain the advantages of running the service in a virtual machine. For example, services on the host machine or on other virtual machines cannot be compromised or crashed by a vulnerability or a bug in the service, and the service can run in a different operating system than the host system.

To configure port forwarding you can use the graphical Port Forwarding editor which can be found in the Network settings dialog for network adaptors configured to use NAT. Here, you can map host ports to guest ports to allow network traffic to be routed to a specific port in the guest.

Alternatively, the command line tool VBoxManage can be used. See VBoxManage modifyvm.

You will need to know which ports on the guest the service uses and to decide which ports to use on the host. You may want to use the same ports on the guest and on the host. You can use any ports on the host which are not already in use by a service. For example, to set up incoming NAT connections to an ssh server in the guest, use the following command:

VBoxManage modifyvm "VM name" --nat-pf1 "guestssh,tcp,,2222,,22"

In the above example, all TCP traffic arriving on port 2222 on any host interface will be forwarded to port 22 in the guest. The protocol name tcp is a mandatory attribute defining which protocol should be used for forwarding, udp could also be used. The name guestssh is purely descriptive and will be auto-generated if omitted. The number after --nat-pf denotes the network card, as with other VBoxManage commands.

To remove this forwarding rule, use the following command:

VBoxManage modifyvm "VM name" --natpf1 delete "guestssh"

If for some reason the guest uses a static assigned IP address not leased from the built-in DHCP server, it is required to specify the guest IP when registering the forwarding rule, as follows:

VBoxManage modifyvm "VM name" --natpf1 "guestssh,tcp,,2222,10.0.2.19,22"

This example is identical to the previous one, except that the NAT engine is being told that the guest can be found at the 10.0.2.19 address.

To forward all incoming traffic from a specific host interface to the guest, specify the IP of that host interface as follows:

VBoxManage modifyvm "VM name" --natpf1 "guestssh,tcp,127.0.0.1,2222,,22"

This example forwards all TCP traffic arriving on the localhost interface at 127.0.0.1 through port 2222 to port 22 in the guest.

It is possible to configure incoming NAT connections while the VM is running, see VBoxManage controlvm.

PXE booting is now supported in NAT mode. The NAT DHCP server provides a boot file name of the form vmname.pxe if the directory TFTP exists in the directory where the user's VirtualBox.xml file is kept. It is the responsibility of the user to provide vmname.pxe.

There are some limitations of NAT mode which users should be aware of, as follows:

• ICMP protocol limitations. Some frequently used network debugging tools, such as ping or traceroute, rely on the ICMP protocol for sending and receiving messages. Oracle VirtualBox ICMP support has some limitations, meaning ping should work but some other tools may not work reliably.

• Receiving of UDP broadcasts. The guest does not reliably receive UDP broadcasts. In order to save resources, it only listens for a certain amount of time after the guest has sent UDP data on a particular port. As a consequence, NetBios name resolution based on broadcasts does not always work, but WINS always works. As a workaround, you can use the numeric IP of the required server in the \\server\share notation.

• Some protocols are not supported. Protocols other than TCP and UDP are not supported. GRE is not supported. This means some VPN products, such as PPTP from Microsoft, cannot be used. There are other VPN products which use only TCP and UDP.

• Forwarding host ports below 1024. On UNIX-based hosts, such as Linux, Oracle Solaris, and macOS, it is not possible to bind to ports below 1024 from applications that are not run by root. As a result, if you try to configure such a port forwarding, the VM will refuse to start.

These limitations normally do not affect standard network use. But the presence of NAT has also subtle effects that may interfere with protocols that are normally working. One example is NFS, where the server is often configured to refuse connections from non-privileged ports, which are those ports above 1024.

The Host-Only Networks tab in Network Manager lists all host-only networks that are currently in use.

• Click Create to add a new host-only network to the list.

• Click Remove to remove a host-only network from the list.

• Click Properties to show or hide settings for the selected host-only network.

To configure a host-only network, select the network name in the Name field and do the following:

• Use the Adapter tab to configure the network adapter for the host-only network.

• Use the DHCP Server tab to configure settings for the DHCP server used by the host-only network. The DHCP server is built into Oracle VirtualBox and manages IP addresses for the network automatically.

The NAT Networks tab in Network Manager lists all NAT networks that are currently in use.

• Click Create to add a new NAT network to the list.

• Click Remove to remove a NAT network from the list.

• Click Properties to show or hide settings for the selected NAT network.

To configure a NAT network, select the network name in the Name field and do the following:

• Use the General Options tab to configure the network settings used by the NAT network. For example, the network address and mask of the NAT service interface.

• Use the Port Forwarding tab to configure port forwarding rules used by the NAT network.

The Cloud Networks tab in Network Manager lists all cloud networks that are currently in use.

• Click Create to add a new cloud network to the list.

• Click Remove to remove a cloud network from the list.

• Click Properties to show or hide settings for the selected cloud network.

To configure a cloud network, select the network name in the Name field and specify the following:

• Name: The name used for the cloud network.

• Provider: The cloud service provider, such as Oracle Cloud Infrastructure.

• Profile: The cloud profile used to connect to the cloud network.

• ID: The OCID for the cloud tunneling network. Click the Network icon to view the subnets on Oracle Cloud Infrastructure that are available for tunneling traffic.

  See Using a Cloud Network for details of how you can use the VBoxManage cloud command to create and configure a virtual cloud network (VCN) on Oracle Cloud Infrastructure.

Since VRDP is backward-compatible to RDP, you can use any standard RDP viewer to connect to such a remote virtual machine. For this to work, you must specify the IP address of your host system, not of the virtual machine, as the server address to connect to. You must also specify the port number that the VRDP server is using.

The following examples are for the most common RDP viewers:

• On Windows, you can use the Microsoft Terminal Services Connector, mstsc.exe, that is included with Windows. Press the Windows key + R, to display the Run dialog. Enter mstsc to start the program. You can also find the program in Start, All Programs, Accessories, Remote Desktop Connection. If you use the Run dialog, you can enter options directly. For example:

  mstsc 1.2.3.4:3389

  Replace 1.2.3.4 with the host IP address, and 3389 with a different port, if necessary.

  Note:

  • IPv6 addresses must be enclosed in square brackets to specify a port. For example: mstsc [fe80::1:2:3:4]:3389

  • When connecting to localhost in order to test the connection, the addresses localhost and 127.0.0.1 might not work using mstsc.exe. Instead, the address 127.0.0.2[:3389] has to be used.

• On other systems, you can use the standard open source rdesktop program. This ships with most Linux distributions.

  With rdesktop, use a command line such as the following:

  $ rdesktop -a 16 -N 1.2.3.4:3389

  Replace 1.2.3.4 with the host IP address, and 3389 with a different port, if necessary. The -a 16 option requests a color depth of 16 bits per pixel, which we recommend. For best performance, after installation of the guest operating system, you should set its display color depth to the same value. The -N option enables use of the NumPad keys.

• You can use the Remmina remote desktop client with VRDP. This application is included with some Linux distributions, such as Debian and Ubuntu.

• If you run the KDE desktop, you can use krdc, the KDE RDP viewer. A typical command line is as follows:

  $ krdc rdp://1.2.3.4:3389

  Replace 1.2.3.4 with the host IP address, and 3389 with a different port, if necessary. The rdp:// prefix is required with krdc to switch it into RDP mode.

• With Sun Ray thin clients you can use uttsc, which is part of the Sun Ray Windows Connector package. See the Sun Ray documentation for details.

While any VM started from VirtualBox Manager is capable of running virtual machines remotely, it is not convenient to have to run the full GUI if you never want to have VMs displayed locally in the first place. In particular, if you are running server hardware whose only purpose is to host VMs, and all your VMs are supposed to run remotely over VRDP, then it is pointless to have a graphical user interface on the server at all. This is especially true for Linux or Oracle Solaris hosts, as the VirtualBox Manager comes with dependencies on the Qt and SDL libraries. This is inconvenient if you would rather not have the X Window system on your server at all.

Oracle VirtualBox therefore comes with a front end called VBoxHeadless, which produces no visible output on the host at all, but still can optionally deliver VRDP data. This front end has no dependencies on the X Window system on Linux and Oracle Solaris hosts.

To start a virtual machine with VBoxHeadless, you have the following options:

• Use the VBoxManage command, as follows:

  $ VBoxManage startvm VM-name --type headless

  The --type option causes Oracle VirtualBox to use VBoxHeadless as the front end to the internal virtualization engine, instead of the Qt front end.

• Use the VBoxHeadless command, as follows:

  VBoxHeadless --startvm uuid|vmname
                          

  This way of starting the VM helps troubleshooting problems reported by VBoxManage startvm, because you can sometimes see more detailed error messages, especially for early failures before the VM execution is started. In normal situations VBoxManage startvm is preferred, since it runs the VM directly as a background process which has to be done explicitly when directly starting with VBoxHeadless.

• Start VBoxHeadless from VirtualBox Manager, by pressing the Shift key when starting a virtual machine or by selecting Headless Start from the Machine menu.

When you use the VBoxHeadless command to start a VM, the VRDP server will be enabled according to the VM configuration. You can override the VM's setting using --vrde command line parameter. To enable the VRDP server, start the VM as follows:

VBoxHeadless --startvm uuid|vmname --vrde on

To disable the VRDP server:

VBoxHeadless --startvm uuid|vmname --vrde off

To have the VRDP server enabled depending on the VM configuration, as for other front ends:

VBoxHeadless --startvm uuid|vmname --vrde config

This command is the same as the following:

VBoxHeadless --startvm uuid|vmname
                  

If you start the VM with VBoxManage startvm then the configuration settings of the VM are always used.

The following instructions describe how to create a virtual machine on a headless server over a network connection. This example creates a virtual machine, establishes an RDP connection and installs a guest operating system. All of these tasks are done without having to touch the headless server. You need the following prerequisites:

• Oracle VirtualBox on a server machine with a supported host operating system. The Oracle VirtualBox Extension Pack for the VRDP server must be installed, see Remote Display (VRDP Support). The procedures assume a Linux server is used.

• An ISO file accessible from the server, containing the installation data for the guest operating system to install. Windows XP is used in the example.

• A terminal connection to that host through which you can access a command line, such as ssh.

• An RDP viewer on the remote client. See Common Third-Party RDP Viewers for examples.

Note that on the server machine, since we will only use the headless server, Qt and the X Window system are not required.

1. On the headless server, create a new virtual machine. For example:

   VBoxManage createvm --name "Windows XP" --ostype WindowsXP --register

   If you do not specify --register, you will have to manually use the registervm command later.

   You do not need to specify --ostype, but doing so selects some sensible default values for certain VM parameters. For example, the RAM size and the type of the virtual network device. To get a complete list of supported operating systems you can use the following command:

   VBoxManage list ostypes

2. Ensure the settings for the VM are appropriate for the guest operating system that we will install. For example:

   VBoxManage modifyvm "Windows XP" --memory 256 --acpi on --boot1 dvd --nic1 nat

3. Create a virtual hard disk for the VM. For example, to create a 10 GB virtual hard disk:

   VBoxManage createhd --filename "WinXP.vdi" --size 10000

4. Add an IDE Controller to the new VM. For example:

   VBoxManage storagectl "Windows XP" --name "IDE Controller"
     --add ide --controller PIIX4

5. Set the VDI file you created as the first virtual hard disk of the new VM. For example:

   VBoxManage storageattach "Windows XP" --storagectl "IDE Controller"
    --port 0 --device 0 --type hdd --medium "WinXP.vdi"

6. Attach the ISO file that contains the operating system installation that you want to install later to the virtual machine. This is done so that the VM can boot from it.

   VBoxManage storageattach "Windows XP" --storagectl "IDE Controller"
    --port 0 --device 1 --type dvddrive --medium /full/path/to/iso.iso

7. Enable the VirtualBox Remote Desktop Extension, the VRDP server, as follows:

   VBoxManage modifyvm "Windows XP" --vrde on

8. Start the virtual machine using the VBoxHeadless command:

   VBoxHeadless --startvm "Windows XP"

   If the configuration steps worked, you should see a copyright notice. If you are returned to the command line, then something did not work correctly.

9. On the client machine, start the RDP viewer and connect to the server. See Common Third-Party RDP Viewers for details of how to use various common RDP viewers.

   The installation routine of your guest operating system should be displayed in the RDP viewer.

Separate mode is an alternative front end for local and remote virtual machines. Separate mode is based on the VBoxHeadless front end but uses the VirtualBox Manager user interface to control and display virtual machines, rather than an RDP viewer program. The VirtualBox Remote Desktop Extension (VRDE) is not required for separate mode.

Separate mode enables the guest graphical user interface to easily attach to and detach from a running VM. Users with several running VMs can use separate mode to display the required VM, while keeping all other VMs in the background until they are needed.

Separate mode has some security advantages, compared to using the VBoxHeadless front end.

As a special feature additional to the VRDP support, Oracle VirtualBox also supports remote USB devices over the wire. That is, an Oracle VirtualBox guest that runs on one computer can access the USB devices of the remote computer on which the VRDP data is being displayed the same way as USB devices that are connected to the actual host. This enables running of virtual machines on an Oracle VirtualBox host that acts as a server, where a client can connect from elsewhere that needs only a network adapter and a display capable of running an RDP viewer. When USB devices are plugged into the client, the remote Oracle VirtualBox server can access them.

For these remote USB devices, the same filter rules apply as for other USB devices. See USB Settings. All you have to do is specify Remote, or Any, when setting up these rules.

Accessing remote USB devices is only possible if the RDP client supports this extension. Some versions of uttsc, a client tailored for the use with Sun Ray thin clients, support accessing remote USB devices. RDP clients for other platforms will be provided in future Oracle VirtualBox versions.

For each virtual machine that is remotely accessible using RDP, you can individually determine if and how client connections are authenticated. For this, use the VBoxManage modifyvm command with the --vrde-auth-type option. See VBoxManage modifyvm. The following methods of authentication are available:

• The null method means that there is no authentication at all. Any client can connect to the VRDP server and thus the virtual machine. This is very insecure and only to be recommended for private networks.

• The external method provides external authentication through a special authentication library. Oracle VirtualBox ships with two special authentication libraries:

  1. The default authentication library, VBoxAuth, authenticates against user credentials of the hosts. Depending on the host platform, this means the following:

     • On Linux and Oracle Solaris hosts, VBoxAuth.so authenticates users against the host's PAM system.

     • On Windows hosts, VBoxAuth.dll authenticates users against the host's WinLogon system.

     • On macOS hosts, VBoxAuth.dylib authenticates users against the host's directory service.

     In other words, the external method by default performs authentication with the user accounts that exist on the host system. Any user with valid authentication credentials is accepted. For example, the username does not have to correspond to the user running the VM.

  2. An additional library called VBoxAuthSimple performs authentication against credentials configured in the extradata section of a virtual machine's XML settings file. This is probably the simplest way to get authentication that does not depend on a running and supported guest. The following steps are required:

     1. Enable VBoxAuthSimple with the following command:

        VBoxManage setproperty vrdeauthlibrary "VBoxAuthSimple"

     2. To enable the library for a particular VM, you must switch authentication to external, as follows:

        VBoxManage modifyvm VM-name --vrde-auth-type external

        Replace VM-name with the VM name or UUID.

     3. You then need to configure users and passwords by writing items into the machine's extradata. Since the XML machine settings file, into whose extradata section the password needs to be written, is a plain text file, Oracle VirtualBox uses hashes to encrypt passwords. The following command must be used:

        VBoxManage setextradata VM-name "VBoxAuthSimple/users/user" hash
                                            

        Replace VM-name with the VM name or UUID, user with the user name who should be allowed to log in and hash with the encrypted password. The following command example obtains the hash value for the password secret:

        $ VBoxManage internalcommands passwordhash "secret"
        2bb80d537b1da3e38bd30361aa855686bde0eacd7162fef6a25fe97bf527a25b

        You then use VBoxManage setextradata to store this value in the machine's extradata section.

        As a combined example, to set the password for the user john and the machine My VM to secret, use this command:

        VBoxManage setextradata "My VM" "VBoxAuthSimple/users/john"
            2bb80d537b1da3e38bd30361aa855686bde0eacd7162fef6a25fe97bf527a25b

• The guest authentication method performs authentication with a special component that comes with the Guest Additions. As a result, authentication is not performed on the host, but with the guest user accounts.

  This method is currently still in testing and not yet supported.

In addition to the methods described above, you can replace the default external authentication module with any other module. For this, Oracle VirtualBox provides a well-defined interface that enables you to write your own authentication module. This is described in detail in the Oracle VirtualBox Software Development Kit (SDK) reference. See Oracle VirtualBox Programming Interfaces.

RDP features data stream encryption, which is based on the RC4 symmetric cipher, with keys up to 128-bit. The RC4 keys are replaced at regular intervals, every 4096 packets.

RDP provides the following different authentication methods:

• RDP 4 authentication was used historically. With RDP 4, the RDP client does not perform any checks in order to verify the identity of the server it connects to. Since user credentials can be obtained using a man in the middle (MITM) attack, RDP4 authentication is insecure and should generally not be used.

• RDP 5.1 authentication employs a server certificate for which the client possesses the public key. This way it is guaranteed that the server possess the corresponding private key. However, as this hard-coded private key became public some years ago, RDP 5.1 authentication is also insecure.

• RDP 5.2 or later authentication uses Enhanced RDP Security, which means that an external security protocol is used to secure the connection. RDP 4 and RDP 5.1 use Standard RDP Security. The VRDP server supports Enhanced RDP Security with TLS protocol and, as a part of the TLS handshake, sends the server certificate to the client.

  The Security/Method VRDE property sets the required security method, which is used for a connection. Valid values are as follows:

  • Negotiate. Both Enhanced (TLS) and Standard RDP Security connections are allowed. The security method is negotiated with the client. This is the default setting.

  • RDP. Only Standard RDP Security is accepted.

  • TLS. Only Enhanced RDP Security is accepted. The client must support TLS.

    The version of OpenSSL used by Oracle VirtualBox supports TLS versions 1.0, 1.1, 1.2, and 1.3.

  For example, the following command enables a client to use either Standard or Enhanced RDP Security connection:

  vboxmanage modifyvm VM-name --vrde-property "Security/Method=negotiate"

  If the Security/Method property is set to either Negotiate or TLS, the TLS protocol will be automatically used by the server, if the client supports TLS. However, in order to use TLS the server must possess the Server Certificate, the Server Private Key and the Certificate Authority (CA) Certificate. The following example shows how to generate a server certificate.

  1. Create a CA self signed certificate.

     openssl req -new -x509 -days 365 -extensions v3_ca \
       -keyout ca_key_private.pem -out ca_cert.pem

  2. Generate a server private key and a request for signing.

     openssl genrsa -out server_key_private.pem
     openssl req -new -key server_key_private.pem -out server_req.pem

  3. Generate the server certificate.

     openssl x509 -req -days 365 -in server_req.pem \
       -CA ca_cert.pem -CAkey ca_key_private.pem -set_serial 01 -out server_cert.pem

  The server must be configured to access the required files. For example:

  vboxmanage modifyvm VM-name \
    --vrde-property "Security/CACertificate=path/ca_cert.pem"

  vboxmanage modifyvm VM-name \
    --vrde-property "Security/ServerCertificate=path/server_cert.pem"

  vboxmanage modifyvm VM-name \
    --vrde-property "Security/ServerPrivateKey=path/server_key_private.pem"

As the client that connects to the server determines what type of encryption will be used, with rdesktop, the Linux RDP viewer, use the -4 or -5 options.

The VRDP server of Oracle VirtualBox supports multiple simultaneous connections to the same running VM from different clients. All connected clients see the same screen output and share a mouse pointer and keyboard focus. This is similar to several people using the same computer at the same time, taking turns at the keyboard.

The following command enables multiple connection mode:

VBoxManage modifyvm VM-name --vrde-multi-con on

To access two or more remote VM displays you have to enable the VRDP multiconnection mode. See Multiple Connections to the VRDP Server.

The RDP client can select the virtual monitor number to connect to using the domain login parameter (-d). If the parameter ends with @ followed by a number, Oracle VirtualBox interprets this number as the screen index. The primary guest screen is selected with @1, the first secondary screen is @2, and so on.

The Microsoft RDP 6 client does not let you specify a separate domain name. Instead, enter domain\username in the Username field. For example, @2\name . name must be supplied, and must be the name used to log in if the VRDP server is set up to require credentials. If it is not, you may use any text as the username.

The VRDP server can redirect video streams from the guest to the RDP client. Video frames are compressed using the JPEG algorithm allowing a higher compression ratio than standard RDP bitmap compression methods. It is possible to increase the compression ratio by lowering the video quality.

The VRDP server automatically detects video streams in a guest as frequently updated rectangular areas. As a result, this method works with any guest operating system without having to install additional software in the guest. In particular, the Guest Additions are not required.

On the client side, however, currently only the Windows 7 Remote Desktop Connection client supports this feature. If a client does not support video redirection, the VRDP server falls back to regular bitmap updates.

The following command enables video redirection:

VBoxManage modifyvm VM-name --vrde-video-channel on

The quality of the video is defined as a value from 10 to 100 percent, representing a JPEG compression level, where lower numbers mean lower quality but higher compression. The quality can be changed using the following command:

VBoxManage modifyvm VM-name --vrde-video-channel-quality 75

You can disable display output, mouse and keyboard input, audio, remote USB, or clipboard individually in the VRDP server.

The following commands change the corresponding server settings:

$ VBoxManage modifyvm VM-name --vrde-property Client/DisableDisplay=1
$ VBoxManage modifyvm VM-name --vrde-property Client/DisableInput=1
$ VBoxManage modifyvm VM-name --vrde-property Client/DisableUSB=1
$ VBoxManage modifyvm VM-name --vrde-property Client/DisableAudio=1
$ VBoxManage modifyvm VM-name --vrde-property Client/DisableClipboard=1
$ VBoxManage modifyvm VM-name --vrde-property Client/DisableUpstreamAudio=1

To reenable a feature, use a similar command without the trailing 1. For example:

$ VBoxManage modifyvm VM-name --vrde-property Client/DisableDisplay=

The VBoxHeadless command is an alternate front end that enables you to remotely manage virtual machines (VMs). The front end is a CLI rather than the VirtualBox Manager graphical user interface (GUI).

For information about using this command, see VBoxHeadless, the Remote Desktop Server.

The following command starts the ol7u4 VM:

$ VBoxHeadless --startvm "ol7u4"

The following command starts the ol7u6 VM in the Paused state.

$ VBoxHeadless --startvm "ol7u6" --start-paused

The following command starts the ol7u6 VM and records the session. The recording is saved to the ol7u6-recording WebM file.

$ VBoxHeadless --startvm "ol7u6" --capture --filename ol7u6-recording.webm

VBoxManage list, VBoxManage startvm