Cannot resize instance even with enable_resize

Hi,

I have installed a charmed openstack and used the following options for nova.

  nova-compute:
annotations:
  gui-x: '190'
  gui-y: '890'
charm: cs:nova-compute
num_units: 6
options:
  customize-failure-domain: true
  libvirt-image-backend: rbd
  rbd-pool: cinder-ceph
  config-flags: default_ephemeral_format=ext4
  enable-live-migration: true
  enable-resize: true
  migration-auth-type: ssh
  openstack-origin: *openstack-origin

Where enable-resize is set to true. However, resizing an instance fails with the following output from the compute node:

2022-07-07 13:56:11.707 1527065 INFO nova.compute.manager [req-2a246967-4674-4db4-9746-6ff28beb1128 c157f238595f4591953c8da5f13fce48 4bdb0102da3744fa8e731560dbff8abc - default default] [instance: 99888927-93d5-4a0c-9d93-787e7996371b] Setting instance back to active after: Instance rollback performed due to: Resize error: not able to execute ssh command: Unexpected error while running command.
Command: ssh -o BatchMode=yes 172.16.75.9 mkdir -p /var/lib/nova/instances/99888927-93d5-4a0c-9d93-787e7996371b
Exit code: 1
Stdout: ''
Stderr: ''
2022-07-07 13:56:12.311 1527065 INFO nova.compute.manager [req-2a246967-4674-4db4-9746-6ff28beb1128 c157f238595f4591953c8da5f13fce48 4bdb0102da3744fa8e731560dbff8abc - default default] [instance: 99888927-93d5-4a0c-9d93-787e7996371b] Swapping old allocation on dict_keys(['46fe4f68-5be1-4712-ae7c-1293450f76ed']) held by migration 66d05a30-2f50-40a4-8cd0-07d249395719 for instance
2022-07-07 13:56:13.059 1527065 INFO nova.compute.manager [req-2a246967-4674-4db4-9746-6ff28beb1128 c157f238595f4591953c8da5f13fce48 4bdb0102da3744fa8e731560dbff8abc - default default] [instance: 99888927-93d5-4a0c-9d93-787e7996371b] Successfully reverted task state from None on failure for instance.
2022-07-07 13:56:13.073 1527065 ERROR oslo_messaging.rpc.server [req-2a246967-4674-4db4-9746-6ff28beb1128 c157f238595f4591953c8da5f13fce48 4bdb0102da3744fa8e731560dbff8abc - default default] Exception during message handling: nova.exception.ResizeError: Resize error: not able to execute ssh command: Unexpected error while running command.
Command: ssh -o BatchMode=yes 172.16.75.9 mkdir -p /var/lib/nova/instances/99888927-93d5-4a0c-9d93-787e7996371b
Exit code: 1

Do you have any ideas as to why this is failing?

Greetings,

Carlos.

I’m thinking that the new flavor and the scheduler are dictating that the disk must be moved to another hypervisor and that SSH keys are not set up for inter-hypervisor communication.

https://docs.openstack.org/nova/yoga/admin/ssh-configuration.html