nfs: support internal ganesha with external ceph cluster

[guits]

This commits allows to deploy an internal ganesha with an external ceph cluster.

This requires to define external_cluster_mon_ips with a comma
separated list of external monitors.

Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1710358

Signed-off-by: Guillaume Abrioux gabrioux@redhat.com

[guits]

container won't start because of this: https://github.com/ceph/ceph-container/blob/master/src/daemon/start_nfs.sh#L20-L23

[gfidente]

I think having to provision the Ganesha client keyring on the ceph-nfs nodes makes perfect sense; I think that can be configured using the "ceph_nfs_ceph_user" variable and provisioned on the node using the "keys" structure (from ceph-client role)? What do you think?

[guits]

@gfidente the variable nfs_obj_gw is True by default in ceph-ansible.

the template for ganesha.conf has this code which requires ceph_nfs_rgw_access_key and ceph_nfs_rgw_secret_key to be set.
Usually ceph-ansible generates them itself here
but in this use case, it means they have to be manually set. Is that ok for you?

[gfidente]

I think that would be okay ... and in TripleO we only want the MDS FSAL so we disable nfs_obj_gw [1]; do you think things will work when it is disabled?

1. https://github.com/openstack/tripleo-heat-templates/blob/master/deployment/ceph-ansible/ceph-nfs.yaml#L59

[guits]

@gfidente yes, it will work.

[guits]

jenkins test pipeline