Volume creation on a multipath device randomly fails in Red Hat OpenStack due to long delays in creating multipath maps

Issue

• The instance-xxxx.xml for attached disks to a live-migrated instance uses a /dev/sd* and not a dm-* device
• Attaching or live-migrating a vm randomly leads to have volumes attached using single paths only and not the expected dm-* multipath device. Some volumes are visible as multipath devices, some not.

• Creating volumes fails with messages similar to:

  2024-07-23 10:52:38.096 11 ERROR cinder.volume.volume_utils Command: qemu-img convert -O raw -t none -f qcow2 /var/lib/cinder/conversion/<image> /dev/dm-7
  2024-07-23 10:52:38.096 11 ERROR cinder.volume.volume_utils Exit code: 1
  2024-07-23 10:52:38.096 11 ERROR cinder.volume.volume_utils Stdout: ''
  2024-07-23 10:52:38.096 11 ERROR cinder.volume.volume_utils Stderr: 'qemu-img: /dev/dm-7: error while converting raw: Cannot grow device files\n'