Can I Live Migrate an Instance Across Availability Zones?¶
Problem: Live migration of instance across availability zone is failing. Below messages are reported in logs /var/log/nova/nova-conductor.log
:
WARNING nova.scheduler.utils [...] Failed to compute_task_migrate_server: No valid host was found
And in logs /var/log/nova/nova-scheduler.log
:
INFO nova.scheduler.host_manager [...] Host filter only checking host [...] and node [hostname]INFO nova.filters [...] Filter AvailabilityZoneFilter returned 0 hosts
Environment:
- Platform managed OpenStack - All versions
- Nova
Cause:
Live migration of instance is possible across the availability zone but only using CLI. As we can see both the source and destination host are part of different availability zones.
Source Host:
$ openstack compute service list | grep [UUID]| 50 | nova-compute | [UUID] | Test-AZ | enabled | up | 2020-XX-XXTYY:YY:YY.000000 |
Destination Host:
$ openstack compute service list | grep [UUID]| 69 | nova-compute | [UUID] | nova | enabled | up | 2020-XX-XXTYY:YY:YY.000000 |
Resolution:
Live migration between different availability zones works with the --force
parameter to live-migration. Migrating instances using --force
option, can forcefully bypass the nova-scheduler
and move an instance to a specified host:
https://docs.openstack.org/nova/latest/admin/availability-zones.html
Additional Information:
Refer the OpenStack documentation for more details on the Availability Zones docs.