Live Migration Fails With Error: "Unacceptable CPU Info: CPU Doesn't Have Compatibility."

Problem

Attempts to perform a live migration of an instance fail with the following error.

Unacceptable CPU info: CPU doesn’t have compatibility.

Environment

Platform9 Managed OpenStack - v3.6.0 and Higher

Cause

This error presents itself when CPU model/architecture differ between the source host and destination host even slightly.

Resolution

Run the following command on the host where the VM currently resides to create an XML with the full CPU description.

# virsh capabilities > virsh-caps-<originHostname>-full.xml

Edit the XML file you’ve generated deleting everything above “” and everything below “”.

Move the file to the destination host and run the following command which will tell you if there is a legitimate mismatch and on which side it lies.

# virsh cpu-compare virsh-caps-<originHostname>-full.xml

To determine the specific features that must be masked out, run the following command.

# virsh cpu-baseline virsh-caps-<originHostname>-full.xml

Mask out the features that do not appear in the output of the command in Step #4 and attempt to migrate the VM again.