[libvirt-users] Preventing 'virsh start' while doing backup?

[Eric Blake]

On 01/25/2012 04:34 PM, Ken Coar wrote:
> Is there any way to interface with virsh to keep it from executing a
> startup operation?  Sort of like the /etc/nologin (man page nologin(5))
> mechanism?
> 
> Basically, I want to be able to shut down a VM in order to copy its
> disk images, and be reasonably assured that it won't be started
> before I'm finished.
> 
> Is there any sort of hook or interlock file or other mechanism to
> accomplish this?

Libvirt has startup hooks; if the hook fails, the domain won't be
started.  So you could write a hook that checks if the domain about to
be started is on your black-list because you are in the middle of some
other operation on the disk image.  You do have to restart libvirtd to
recognize a newly added hook, though.  http://libvirt.org/hooks.html

Libvirt also has the ability to interact with the sanlock file lock
manager; if you configure libvirt to use the lock manager, and then you
can independently take out a lease on a disk image, then you can lock
out libvirt from starting any domain with that image.
http://libvirt.org/locking.html

-- 
Eric Blake   eblake at redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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