[vbox-dev] Fail to restore snapshot remotely

[Klaus Espenlaub]

On 10.08.2010 17:00, Alex wrote:
> I try to restore the snapshot of a Saved/PowerDown machine but fail.
>
> The VM has a snapshot called 'snapshot' before it's powered on. The VM
> has been
> powered on by IVirtualBox::openRemoteSession().
>
> <code>
>    // 'manager' is a IWebSessionManager objec
>    // 'vbox' is a IVirtualBox object
>    ISession session = manager.getSesscionObject(vbox);
>    // machine
>    vbox.openExistingSession(session, machine.getId());
>    ISnapshot snapshot1 = machine.findSnapshot("snapshot1");
>    IProgress progress = session.getConsole().saveState();
>    progress.waitForCompletion(-1);
>    long result = progress.getResultCode();
>    session.getConsole().restoreSnapshot(snapshot);
> <code>
>
> Error from vboxwebsrv.exe:
>
>    API return code:            0x80BB0002 (VBOX_E_INVALID_VM_STATE)
>    COM error info result code: 0x80BB0002
>    COM error info text:        The virtual machine is being powered down

This means you're trying to perform an operation which requires a 
powered off VM on a VM which is not yet powered down. I can't comment on 
what reason one could have to save the VM state and then immediately run 
restoreSnapshot() with that VM... it makes no sense whatsoever to me.

> Several notes:
> * Even if I do powerDown() instead of saveState(),restoreSnapshot()
> still fails.

You need to wait until the VM is truly powered off, if you do the call 
to restoreSnapshot too early it'll fail, even if there is no other 
session open.

> * I call ISession::getState() before restoreSnapshot(), and it's CLOSED.
> This confuse me. The documentations says restoreSnapshot() cannot be
> executed on a running machine, so I power it down first, but after powering
> down, the session is *closed*, meaning that I cannot use the session object
> to restore the snapshot.

The session state is not the same as the machine state.

> * I notice that phpvirtualbox doesn't use IWebSessionManager and neither
> openRemoteSession(). Instead it uses openSession() to open a direct session.
> I cannot do this since I am doing every operations remotely instead of
> writing a
> frontend.

That cannot be true - for starting a VM phpvirtualbox must also use 
openRemoteSession. It is not a frontend which can run VMs on its own. I 
hope you're not looking at the latest version of phpvirtualbox, which is 
designed to run with the latest VirtualBox version from the subversion 
repository, where API calls have been changed, moved and renamed a lot. 
Especially in the session area.

There's so much confusion that I cannot really say much about the true 
cause of the problem, but I hope I gave a few hints which makes the 
picture somewhat clearer.

Klaus

>
> Alex Barna.