Xen devel - Nov 2007 - Notification on a domU creation and a XenBus watch question

Hi,

I am writing a module for dom0 which needs to be notified when a domain is
created/destroyed. Is that possible? And is it possible to add a watch on
all /local/domain/<id>/path/key without specifying the domain ID? I mean
the
watch should be on all /path/key of the currently executing domains. Does
XenBus support this or will I have to individually add a watch on all
/local/domain/<id>/path/keys?


Regards,
Ashutosh


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You should be able to put a watch on the special path of

"@introduceDomain" and
"@releaseDomain"

to catch cases of doman construction / descruction.

Hope that helps

Ben

ashutosh mehra wrote:
> Hi,
>
> I am writing a module for dom0 which needs to be notified when a 
> domain is created/destroyed. Is that possible? And is it possible to 
> add a watch on all /local/domain/<id>/path/key without specifying the
> domain ID? I mean the watch should be on all /path/key of the 
> currently executing domains. Does XenBus support this or will I have 
> to individually add a watch on all  /local/domain/<id>/path/keys?
>
>
> Regards,
> Ashutosh
> ------------------------------------------------------------------------
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>   


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Hi,

Thanks, that worked! Where are these documented? :) Now how do I iterate
over the domains? for_each_domain is defined in xen/sched.h, but when I try
to include it I get an error that there''s no such file!

Also, can I add a "generic" watch on all /local/domain/*/path/key
without
specifying the domain ID? Or will I have to individually add a watch on all
/local/domain/<id>/path/keys?

Thanks,
Ashutosh



On Nov 8, 2007 12:44 AM, Ben Guthro < bguthro@virtualiron.com> wrote:
>  You should be able to put a watch on the special path of
>
> "@introduceDomain" and
> "@releaseDomain"
>
> to catch cases of doman construction / descruction.
>
> Hope that helps
>
> Ben
>
> ashutosh mehra wrote:
>
> Hi,
>
> I am writing a module for dom0 which needs to be notified when a domain is
> created/destroyed. Is that possible? And is it possible to add a watch on
> all /local/domain/<id>/path/key without specifying the domain ID? I
mean the
> watch should be on all /path/key of the currently executing domains. Does
> XenBus support this or will I have to individually add a watch on all
> /local/domain/<id>/path/keys?
>
>
> Regards,
> Ashutosh
>
> ------------------------------
>
> _______________________________________________
> Xen-devel mailing
listXen-devel@lists.xensource.comhttp://lists.xensource.com/xen-devel
>
>
>

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> I am writing a module for dom0 which needs to be notified when a domain is
> created/destroyed. Is that possible?
Do you mean a kernel module?

But yes, if you create the appropriate watches using the XenBus API I think 
you should be able to get notifications.  Or in userspace you can use C or 
Python to register Xenbus watches.
> And is it possible to add a watch on 
> all /local/domain/<id>/path/key without specifying the domain ID? I
mean
> the watch should be on all /path/key of the currently executing domains.
> Does XenBus support this or will I have to individually add a watch on all
> /local/domain/<id>/path/keys?
As far as I know you''d need to register a watch on each path separately
at the
moment...

In the future, I was thinking it might be nice to have a
"/local/services/"
directory which everyone could watch and which domain could post 
notifications in.  e.g. if everyone is interested in the "foo"
service, they
could watch /local/services/foo.  If domain 5 wants to advertise this service 
they''d post into "/local/services/foo/5/" to tell everyone
about it.  I''ve
never got round to implementing it but I''m curious whether this would
suit
the application you have in mind?

Cheers,
Mark

-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

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