[ClusterLabs] Gracefully Failing Live Migrations

[Ken Gaillot]

On Thu, 2024-02-01 at 12:57 -0600, Billy Croan wrote:
> How do I figure out which of the three steps failed and why?

They're normal resource actions: migrate_to, migrate_from, and stop.
You can investigate them in the usual way (status, logs).

> 
> On Thu, Feb 1, 2024 at 11:15 AM Ken Gaillot <kgaillot at redhat.com>
> wrote:
> > On Thu, 2024-02-01 at 10:20 -0600, Billy Croan wrote:
> > > Sometimes I've tried to move a resource from one node to another,
> > and
> > > it migrates live without a problem.  Other times I get 
> > > > Failed Resource Actions:
> > > > * vm_myvm_migrate_to_0 on node1 'unknown error' (1): call=102,
> > > > status=complete, exitreason='myvm: live migration to node2
> > failed:
> > > > 1',
> > > >     last-rc-change='Sat Jan 13 09:13:31 2024', queued=1ms,
> > > > exec=35874ms
> > > > 
> > > 
> > > And I find out the live part of the migration failed, when the vm
> > > reboots and an (albeit minor) outage occurs.
> > > 
> > > Is there a way to configure pacemaker, so that if it is unable to
> > > migrate live it simply does not migrate at all?
> > > 
> > 
> > No. Pacemaker automatically replaces a required stop/start sequence
> > with live migration when possible. If there is a live migration
> > attempted, by definition the resource must move one way or another.
> > Also, live migration involves three steps, and if one of them
> > fails,
> > the resource is in an unknown state, so it must be restarted
> > anyway.
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-- 
Ken Gaillot <kgaillot at redhat.com>