[vbox-dev] Help with sessions

[Lucas Charles]

Hi Nikolay,


Thank you very much for sorting this out, now it's solved.
What I actually didn't get was that I had to close the session after
openRemoteSession. (My bad)

I just had one question, it seems to me that using snapshot (Either restore
the snapshot or start from a saved one) can be really expensive if I have
modifications on the harddrive.. It takes something like 5-10 seconds to
recover form a snapshot that has been done after an install of a few package
in an Ubuntu guest.

- Does it make any sense ?

Lucas

On Mon, Oct 25, 2010 at 4:46 PM, Nikolay Igotti
<nikolay.igotti at oracle.com>wrote:

>  Hi Lucas,
>
>
>
> Lucas Charles wrote:
>
>> Thanks also for reminding me the change of the API, I also remember that
>> there should be an xpcom-like API for java in the next version.
>>
> Yes, but look and feel of both WS and XPCOM API shall be the same, and you
> can use pretty much the same Java code for both.
>
>  I understood that openRemoteSession is used to start a vm and I used this
>> call to open several vms.
>> The problem is how to access this session once it has been opened.
>>
> To create a session object you may want to use getSessionObject(). Complete
> example can be found in
> src/VBox/Main/webservice/samples/java/jax-ws/clienttest.java which is also
> shipped with SDK.
>
>
>
>  Up to know I passed the same session object to every open remote session
>> call, which is apparently wrong.
>> I tried to reused this session object to command the snapshots, and it
>> apparently failed. I understood that a session is
>> linked to one machine, so it makes sense that I cannot reuse them
>> everywhere.
>>
> Yes, you need one session per machine. See my getSessionObject() remark
> above.
>
>
>
>> I saw in some threads in the mailing list that I could create one
>> IWebsessionManager to start all the vms and then
>> create one IWesessionManager per machine started to create new session
>> objects. Is it really the right thing to do, since the IVirtualbox is a
>> singleton.
>>
> You need different managers if you maintain connection to multiple
> VirtualBox hosts, if you all your VMs run on the same host/port
> there is no need for multiple managers.
>
>  Nikolay
>
>
>
>> On Mon, Oct 25, 2010 at 11:14 AM, Nikolay Igotti <
>> nikolay.igotti at oracle.com <mailto:nikolay.igotti at oracle.com>> wrote:
>>
>>       Hi Lucas,
>>
>>
>>    First of all, please keep in mind that for next major release
>>    there will be significant rework of both session API and
>>    the way it's accessed from Java. Having said that, with 3.x
>>     approach, which is, indeed not very straightforward,
>>    openRemoteSession() API is just a way start a new VM, so it's not
>>    possible to use one remote session to start several VMs -
>>    you have to openRemoteSession() for every VM you want to start.
>>    Please refer to SDK documentation, and vboxshell.py TUI example
>>    (while in Python, patterns of API usage is the same).
>>
>>
>>    Hope that will help,
>>      Nikolay
>>
>>
>>    Lucas Charles wrote:
>>
>>        Hello everyone,
>>
>>        I'm stuck with a problem related to the sdk for java-ws.
>>        I want to manage several machines on a given host from my java
>>        client.
>>
>>        I need to start vms Take snapshots of the one I started at
>>        given intervals.
>>        After a new boot I need to restore the machines to their
>>        latest snapshot.
>>        Start them and redo snapshots.
>>
>>        The problem I'm facing is how to open sessions.
>>
>>        Yet I'm starting the vms by calling
>>        ------
>>
>>        IWebsessionManager mgr;
>>
>>        IVirtualBox vbox
>>
>>        mgr = new IWebsessionManager("http://localhost:18083");
>>
>>        vbox = mgr.logon("", "");
>>
>>        ISession session = mgr.getSessionObject(vbox);
>>
>>        IProgress prog = vbox.openRemoteSession(session,
>>        machineToStart.getId(), "gui", "");
>>
>>        prog.waitForCompletion(-1);
>>
>>        -----
>>
>>        Isn't it a problem to call openRemoteSession with the session
>>        I got from IWebSessionManager::getSessiontObject() ?
>>        Because I then use only one session to start several vms.
>>
>>        My next question is when I want to take snapshots of every
>>        machines I have in charge.
>>
>>        Which session object should I use to get the IConsole ?
>>        Can/Must I reuse the one I used upon calling
>>        openRemoteSession() ? Reusing seems to work, if I control only
>>        one machine but fails with more than one.
>>
>>        Best Regard,
>>        Lucas Charles
>>
>>  ------------------------------------------------------------------------
>>
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>>
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>>
>>
>>
>>
>
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