[libvirt-users] snapshots with virsh in a pacemaker cluster

[Doug Hughes]

I snapshot my guests live with qemu-guest-agent. It works pretty much 
flawlessly with qcow2, but even with raw I can almost always boot off of 
a snapshot. I combine this with zfs and hourly snapshots and replication 
and have a really usable backup and DR system that works with my guests, 
both Windows and Linux.

You should test it with qemu-guest-agent and then try to boot off of it 
and see if you run into issues. I've been doing this for 2+ years.


On 10/15/2018 3:29 PM, Lentes, Bernd wrote:
> Hi,
>
> i have a two node cluster with virtual guests as resources.
> I'd like to snapshot the guests once in the night and thought i had a procedure.
> But i realize that things in a cluster are a bit more complicated than expected :-))
>
> I will shutdown the guests to have a clean snapshot.
> I can shutdown the guests via pacemaker.
> But then arises the first problem:
>
> When i issue a "virsh snapshot-create-as" libvirt needs the domain name as a parameter.
> but libvirt does not know the domains any longer. When the guests are shutdown a "virsh list --all"
> on both nodes does not show any domain.
>
> A look in the respective resource agent VirtualDomain explains why:
> The domain is started with virsh create:
>
> "# The 'create' command guarantees that the domain will be
> # undefined on shutdown, ...
>
> OK: Now i could of course define all domains with a virsh define.
>
> But then i have immediately the next problem. Now i'd create the snapshots with
> "virsh snapshot-create-as" and starts the domains afterwards via cluster.
> But let's assume i issue that on node 1 and some guests are started afterwards via pacemaker on node 2.
> I can't predict on which node the guests are starting.
>
> Then i don't get a snapshot, right ?
>
> What to do ?
>
> Bernd
>
>
>

-- 
Doug Hughes
Keystone NAP
Fairless Hills, PA
1.844.KEYBLOCK (439.2562) 	

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/libvirt-users/attachments/20181015/8065c1ab/attachment.htm>