[ClusterLabs] kvm live migration, resource moving

[Cédric Dufour - Idiap Research Institute]

Hello,

Here, we have live migration working like a charm through the cluster.
Below the XML expert of a resource configuration:

<resources>
  <group id="FOOBAR">
    <primitive id="FOOBAR-LibvirtQemu" class="ocf" provider="custom"
type="LibvirtQemu">
      <instance_attributes id="FOOBAR-LibvirtQemu-IA">
        <nvpair id="FOOBAR-LibvirtQemu-IA-config" name="config"
value="/havc/config/libvirt/FOOBAR.xml"/>
      </instance_attributes>
      <meta_attributes id="FOOBAR-LibvirtQemu-MA">
        <nvpair id="FOOBAR-LibvirtQemu-MA-allow-migrate"
name="allow-migrate" value="true"/>
      </meta_attributes>
      <operations>
        <op id="FOOBAR-LibvirtQemu-OP-monitor" name="monitor"
timeout="30s" interval="60s"/>
        <op id="FOOBAR-LibvirtQemu-OP-start" name="start" timeout="60s"
interval="0"/>
        <op id="FOOBAR-LibvirtQemu-OP-stop" name="stop" timeout="60s"
interval="0"/>
        <op id="FOOBAR-LibvirtQemu-OP-migrate-to" name="migrate_to"
timeout="60s" interval="0"/>
        <op id="FOOBAR-LibvirtQemu-OP-migrate-from" name="migrate_from"
timeout="60s" interval="0"/>
      </operations>
    </primitive>
  </group>
</resources>

The LibvirtQemu agent is a custom one derived from the VirtualDomain
agent (for reasons that are off-topic).

The points worth seeing are:

- the "allow-migrate" meta attribute (see
http://www.linux-ha.org/wiki/VirtualDomain_%28resource_agent%29 "If the
allow-migrate meta parameter is set to true, then a resource migration
will not map to a domain shutdown/startup cycle, but to an actual,
potentially live, resource migration between cluster nodes. ")

- the "migrate-from" and "migrate-to" timeouts (which must be set
relative to how big - RAM-wise - your VMs are and the bandwidth
available for migration); passed this timeout, the migration will be
interrupted and the VM will be shutdown/restarted

Hope it helps,

Cédric



On 04/02/16 13:44, Kyle O'Donnell wrote:
> That is helpful but I think I am looking at the wrong documentation:
>
> http://www.linux-ha.org/wiki/VirtualDomain_(resource_agent)
> http://linux-ha.org/doc/man-pages/re-ra-VirtualDomain.html
>
> Can you point me to the docs you are referencing?
>
> ----- Original Message -----
> From: "RaSca" <rasca at miamammausalinux.org>
> To: "users" <users at clusterlabs.org>
> Sent: Thursday, February 4, 2016 6:48:26 AM
> Subject: Re: [ClusterLabs] kvm live migration, resource moving
>
> If your environment is successfully configured even from the libvirt
> side, everything should work out of the box, if it does not work you can
> pass migrate_options to make it work.
>
> From the resource agent documentation:
>
> migrate_options:  Extra virsh options for the guest live migration. You
> can also specify here --migrateuri if the calculated migrate URI is
> unsuitable for your environment. If --migrateuri is set then
> migration_network_suffix and migrateport are effectively ignored. Use
> "%n" as the placeholder for the target node name.
> Please refer to the libvirt documentation for details on guest migration.
>
> Hope this helps,
>