Instance Creation Fails With Error 'Unexpected Build failure Not Rescheduling Build'

Problem

Instance creation fails with the below error:

ERROR nova.compute.manager [req-uuid [user name]] [instance: [instance-uuid]] Unexpected build failure, not rescheduling build.TRACE nova.compute.manager [instance: [instance-uuid]] MessagingTimeout: Timed out waiting for a reply to message ID fbb7342c8d3147e0b6fc96df9f5250bf

Environment

• Platform9 Managed OpenStack All Versions
• Nova
• Libvirtd
• Rabbitmq

Cause

• The instance was scheduled and created on the host, but failed to update Nova DB as the connection timed out due to a communication issue between pf9-ostackhost service on the host and rabbitmq service on the management plane.

List the instances created on the host.

$ sudo virsh list --all

Compare it with the list of instances provided by running below commands.

$ openstack server list --all --host [host_uuid] --fit-width

Resolution

As this is newly created instance, undefine the affected instance on the host by running below command and try recreating the instance.

$ sudo virsh undefine [instance-uuid]