QEMU Image Lock Fail to Start VMs After Host Crashes

Problem

Migrated or Evacuated VMs fail to start on destination host when the source host crashes. The following error is observed in log /var/log/pf9/ostackhost.log.

None

569 ERROR nova.virt.libvirt.driver [req-7638759c-10a6-40c5-86f9-4bda4b2dfb82 masakari services] [instance: 65c55b81-9078-44b4-bb07-95dc5adeadba] Failed to start libvirt guest: internal error: qemu unexpectedly closed the monitor: 2019-10-28T00:39:09.301445Z qemu-kvm: -drive file=/mnt/nfs/instances/65c55b81-9078-44b4-bb07-95dc5adeadba/disk,format=qcow2,if=none,id=drive-virtio-disk0,cache=none: Failed to get "write" lock

Environment

• Platform9 Managed OpenStack - v3.6.0 and Higher
• NFSv3
• QEMU

Cause

• Limitation in NFSv3.

Solution

1. Wait for the crashed host to come back online.
2. Once the crashed host is online, reboot the VMs which failed to get a write-lock.

Additional Information

Bug details