Comment 0 for bug 2028559

When using ceph-ephemeral (libvirt-image-backend=rbd), and VMs booted from image, live migration across different charm apps (such as from nova-compute-kvm to nova-compute-kvm2) fails with the following error:

2023-07-24 14:44:40.004 66943 ERROR nova.virt.libvirt.driver [-] [instance: 392e13f3-1a22-42b7-a2b4-498c469cf159] Live Migration failure: internal error: process exited while connecting to monitor: 2023-07-24T14:44:39.741332Z qemu-system-x86_64: -blockdev {"driver":"rbd","pool":"nova","image":"392e13f3-1a22-42b7-a2b4-498c469cf159_disk","server":[{"host":"10.5.3.246","port":"6789"}],"user":"nova-compute-qua","auth-client-required":["cephx","none"],"key-secret":"libvirt-1-storage-auth-secret0","node-name":"libvirt-1-storage","cache":{"direct":true,"no-flush":false},"auto-read-only":true,"discard":"unmap"}: error connecting: Permission denied: libvirt.libvirtError: internal error: process exited while connecting to monitor: 2023-07-24T14:44:39.741332Z qemu-system-x86_64: -blockdev {"driver":"rbd","pool":"nova","image":"392e13f3-1a22-42b7-a2b4-498c469cf159_disk","server":[{"host":"10.5.3.246","port":"6789"}],"user":"nova-compute-qua","auth-client-required":["cephx","none"],"key-secret":"libvirt-1-storage-auth-secret0","node-name":"libvirt-1-storage","cache":{"direct":true,"no-flush":false},"auto-read-only":true,"discard":"unmap"}: error connecting: Permission denied
2023-07-24 14:44:40.157 66943 ERROR nova.virt.libvirt.driver [-] [instance: 392e13f3-1a22-42b7-a2b4-498c469cf159] Migration operation has aborted

The reason for the above error is that the ceph keys are different for each nova-compute charm app, so the src/dst do not have each other's keys to accomplish the migration successfully.