Re: Is it possible to follow a rebooted domain (with a different ID)?

[Mats Petersson <mats.petersson@citrix.com>]

On 07/01/13 10:48, Razvan Cojocaru wrote:
> Hello,
>
> I have an application, running in dom0 userspace, that receives
> mem_events about a domU HVM guest. At some point, the HVM guest (a
> Windows machine) restarts, at which point I need to shut down my
> userspace application, find it's new ID (with 'xm list'), then re-start
> my application passing the new ID as a parameter.
>
> What I'd like to be able to do is to automatically follow the domain
> after it has started again. Is it possible to do this from dom0
> userspace (using libxc), and if it is, how?
Xenstore will keep track of the name of the domain, which has to be 
unique, so you should be able to "find" your domain again by looking for 
its name. I've just reinstalled everything on my test-box, so I can't 
look at exactly where the name is stored [I don't have any VM's on 
there!], but I think you can figure it out yourself with a bit of 
"xenstore-ls".
>
> A related question is this: is it possible to get notifications from
> userspace about a new domU that's just been started (regardless of
> whether it's a reboot of a previously watched domU or not)?
You can have a xenstore watch for that.

I was looking at some code that does that the other day in xenconsoled 
[it watches for "new domain appearing"]. Have a look at 
xen/tools/console/daemon/io.c (I think!)

--
Mats
>
> Thanks,
> Razvan Cojocaru
>
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