Running scripts at domain creation/destruction?

Running scripts at domain creation/destruction?

[John Byrne]

Are there any hooks for running generic scripts/apps in domain 0 when a 
domain is created or destroyed? I don't see any such thing in 
xend-config.sxp.

Taking it back a step, my desire is to have something in domain 0 export 
the xen console via VNC. The reason for wanting to be available via VNC, 
is that we expect Anthony Ligouri's frame buffer work (or something) to 
eventually provide a VNC virtual console for para-virtualized domains. 
If and when that happens, our tool for viewing consoles remotely will 
continue to work.

Assuming that this is at all viable, does any have a piece of code for 
libvncserver that might be useful as the interface between xenconsoled 
and VNC?

Thanks,

John Byrne

Re: Running scripts at domain creation/destruction?

[Anthony Liguori]

Hi John,

John Byrne wrote:

>
> Are there any hooks for running generic scripts/apps in domain 0 when 
> a domain is created or destroyed? I don't see any such thing in 
> xend-config.sxp.

Since xend configuration files are just python scripts, you could add 
something to the config files.

> Taking it back a step, my desire is to have something in domain 0 
> export the xen console via VNC. The reason for wanting to be available 
> via VNC, is that we expect Anthony Ligouri's frame buffer work (or 
> something) to eventually provide a VNC virtual console for 
> para-virtualized domains. If and when that happens, our tool for 
> viewing consoles remotely will continue to work.
>
> Assuming that this is at all viable, does any have a piece of code for 
> libvncserver that might be useful as the interface between xenconsoled 
> and VNC?

There are a few VNC terminal programs--none are very good (including my 
own).  I've been exploring this area quite a bit.  This is a tough area 
b/c it takes a lot of work to be a full terminal emulator.

An interesting approach would be to use vncserver to create a VNC 
session with the resolution of an xterm and setup the vncrc file to only 
start an X term positioned at 0, 0.  If you don't start a window 
manager, and change the background/foreground color, it should give you 
what you're looking for.

Regards,

Anthony Liguori

> Thanks,
>
> John Byrne
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>

Re: Running scripts at domain creation/destruction?

[Ewan Mellor]

On Fri, Dec 09, 2005 at 05:05:08PM -0800, John Byrne wrote:

> 
> Are there any hooks for running generic scripts/apps in domain 0 when a 
> domain is created or destroyed? I don't see any such thing in 
> xend-config.sxp.

Not per say.  This wouldn't be difficult for you to add though -- Xend has all
the information you need, so you just need to take a start-up and shutdown
script from the domain configuration, call the former on creation of the domain
(asynchronously, I presume), write the latter in the store for retrieval
by Xend, and then call it on domain destruction.

Alternatively, you could write your own tool (in Python or C would be easiest)
and watch the store in the same way as the other tools do, waiting for watches
on @introduceDomain and @releaseDomain.

> Taking it back a step, my desire is to have something in domain 0 export 
> the xen console via VNC. The reason for wanting to be available via VNC, 
> is that we expect Anthony Ligouri's frame buffer work (or something) to 
> eventually provide a VNC virtual console for para-virtualized domains. 
> If and when that happens, our tool for viewing consoles remotely will 
> continue to work.
> 
> Assuming that this is at all viable, does any have a piece of code for 
> libvncserver that might be useful as the interface between xenconsoled 
> and VNC?

I'll let others answer, as I don't know the specifics, but I do know that the
VMX guys use VNC, and I believe that VNC is used on the Xen demo CDs, so there
should be enough code lying around for you to get the bits that you need.

Ewan.