Read-only cinder volumes after cinder-volume container restart

[Matt Anson]

Hi,

On a Kolla-ansible deployed cloud using the Cinder NFS driver and a NetApp storage appliance, some cinder volumes become read-only when cinder-volume is restarted.
This appears to be caused by volume backing-file ownership in /var/lib/cinder.

I don't know if this is unique to the use of NFS exported from a NetApp appliance, but the NetApp NFS share mountpoint
is /var/lib/cinder/mnt/{UUID}, putting volume backing-files at /var/lib/cinder/mnt/{UUID}/volume-{UUID},
not directly under /var/lib/cinder.

This means that the recursive chown operations in both:
https://github.com/openstack/kolla-ansible/blob/ec4af6c90ee94e0f82f13afc09a9a7770bab165c/ansible/roles/cinder/templates/cinder-volume.json.j2#L39-L42
https://github.com/openstack/kolla/blob/b02f643db03694074293858470a1db36246b4a0e/docker/cinder/cinder-volume/extend_start.sh#L3-L5

Result in chown operations on the NFS mountpoint, rather than directly on the volume backing files as intended (I assume!).

Once the correct permissions are applied by hand to the read-only volume backing-files, normal service is resumed.

[Jakub Darmach (darmachj)]

Added the mounth path to exclude section in the config.json, this should help it.