[ClusterLabs] Q: When do I need virtlockd?

[Ulrich Windl]

Hi!

I'm migrating our Xen PVM environment from SLES11 SP4 to SLES15 SP2. As it seems libvirt is the preferred framework to use, so I configured VirtualDomains instead of Xen. I had to move configuration from Xen xm via xen xl to libvirt.
What I couldn't get from the docs is whether and when I need lirtlockd.
Currently I see messages like this, and I don't have the slightest idea what is tried to be locked:

Jan 15 20:03:56 h19 virtlockd[4994]: libvirt version: 6.0.0
Jan 15 20:03:56 h19 virtlockd[4994]: hostname: h19
Jan 15 20:03:56 h19 virtlockd[4994]: resource busy: Lockspace resource '1076b120cb84515c54de74dc163c1a3af2832d51feb0b020dd070d3ed5c96128' is not locked

It seems the locking is for the VM itself:
Jan 15 20:03:56 h19 libvirtd[4596]: Unable to release lease on test-jeos1

Those messages appear when the VM is going to be live-migrated away from the host.

Still migration seems to succeed:
Jan 15 20:03:56 h19 VirtualDomain(prm_xen_test-jeos1)[17548]: INFO: test-jeos1: live migration to h18 succeeded.
Jan 15 20:03:58 h18 VirtualDomain(prm_xen_test-jeos1)[6880]: INFO: test-jeos1: live migration from h19 succeeded.

On the destination node there is no problem with virtlockd. It seems it isn't called even.
However lock files (located on OCFS2) seem to exist there:
h19:~ # ll /var/lib/libvirt/lockd/*
/var/lib/libvirt/lockd/files:
total 0
-rw------- 1 root root 0 Jan 15 20:03 1076b120cb84515c54de74dc163c1a3af2832d51feb0b020dd070d3ed5c96128
-rw------- 1 root root 0 Jan 15 20:03 4c6bebd1f4bc581255b422a65d317f31deef91f777e51ba0daf04419dda7ade5
-rw------- 1 root root 0 Jan 15 13:01 7cc124bc29ec975f78295c33a67159a35c941cbc2f513c637d7285db82d1f13f
-rw------- 1 root root 0 Jan 15 12:38 f9d587c61002c7480f8b86116eb4f7dfa210e52af7e944762f58c2c2f89a6865

So did I make a mistake to put those lock files onto a shared filesystem? A non-shred filesystem won't make much sense IMHO.

So can someone explan, or direct me to some helpful docs?

Regards,
Ulrich