[libvirt] [PATCH 0/2] Support of auto-dump on watchdog event in libvirtd

[Daniel P. Berrange]

On Wed, Nov 17, 2010 at 03:45:05PM +0800, Hu Tao wrote:
> This patch series adds support of auto-dump on watchdog event in
> libvirtd. If a qemu guest is configured with a watchdog device and 
> libvirtd receives a watchdog event from the guest, it can do
> something on the guest, currently `dump' action is defined.
> 
> This patch series adds a new watchdog action `managed', it has a
> subaction wich indicates the action libvirtd will take on a watchdog
> event.
> 
> The meaning of subaction_arg depends on subaction. If subaction is
> `dump', then subaction_arg defines a folder path into which libvirtd
> saves dumpfile.
> 
> An example:
> 
> <watchdog model='i6300esb' action='managed' subaction='dump' subaction_arg='/mnt/data/dumps'>

Is there any need to have both 'action' and 'subaction' here ? I
would think we could just have action='dump' on its own. 

One interesting side not, from the Xen driver we already have a 
bit of XML syntax 

  <on_crash>destroy|restart|rename|preserve|coredump-destroy|coredump-restart</on_crash>

Which we never use with the QEMU driver so far, since we can't
detect whether a guest kernel has crashed or not. I'm wondering
if we shouldn't let one of the watchdog actions be 'crash'
and then take whatever action is specified in <on_crash>.

For the dump location, I think it would suffice to just have a
parameter set globally in /etc/libvirt/qemu.conf  (cf XenD which
just always dumps core to /var/lib/xen/dump/$NAME)

Regards,
Daniel
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