[ovirt-users] VMs HA with cinder volumes

[Nir Soffer]

On Tue, Feb 21, 2017 at 3:20 PM, Matteo Dacrema <mdacrema at enter.eu> wrote:
> Hi Nir,
>
> thank you.
> So, can I use a Ceph backed VM with a lease on gluster?

Should work.

> Also if I detach network from the node hosting the VMs it will not migrated
> to another host.

If you have a lease, detaching the network used to access the leases will
cause sanlock to terminate the vm and expire the lease. In this case the
system should start the vm on another host.

Note that if you have multiple networks, and the network used by the vm
disks is different from the network used to access the leases, all this may
not work in a useful way.

Either the leases will not be accessible while the vm disks are accessible,
leading to killing a good working vm, or the vm disk are not accessible,
pausing the vm, but since the leases are still accessible, the vm will not
release the lease and the system will not be able to start the vm elsewhere.

Maybe you can expose some of the ceph storage using cephfs for the leases?
This will make it more likely that the leases storage domain will fail
when there
is some issue with your ceph cluster.

Another option is to expose ceph block device using iscsi, and use this iscsi
storage domain for the leases. But note that this makes your iscsi gateway
host a single point on failure.

Nir