Expose CephFS snapshots as shadow-copies

create shadow copy with the help of ceph_snapshots module:
- use kernel CephFS mounted share path for cephfs
- use absolute path within the Ceph filesystem for cephfs.vfs
- intall samba-vfs-cephfs on both cephfs and cephfs.vfs

Refer: https://www.samba.org/samba/docs/4.11/man-html/vfs_ceph_snapshots.8.html
Signed-off-by: Shwetha K Acharya <[email protected]>

playbooks/ansible/roles/sit.cephfs/tasks/repo/centos.yml

@@ -2,8 +2,11 @@
 - name: Install ceph related samba packages
   when: inventory_hostname in groups['cluster']
   block:
+    # install VFS module irrespective of the CephFS backend variant
+    # as ceph_snapshots.so which is part of VFS module is required
+    # by all the variants to expose ceph snapshots as Windows VSS
+    # with vfs_cephfs_snapshots
     - name: Install VFS module
-      when: config.be.variant == 'vfs'
       yum:
         name: samba-vfs-cephfs
         state: present

playbooks/ansible/roles/sit.cephfs/templates/smb_share.conf.j2

@@ -1,6 +1,6 @@
 [{{ name }}-{{ config.be.name }}-{{ config.be.variant }}]
 comment = Volume '{{ name }}' from {{ config.be.name }}({{ config.be.variant }})
-vfs objects = acl_xattr
+vfs objects = acl_xattr ceph_snapshots
 {%- if config.be.variant == 'vfs' %} ceph
 ceph:config_file = /etc/ceph/sit.ceph.conf
 ceph:user_id = sit