Automate the /var/lib/ceph backup during recovery phase

To keep strong consistency for Ceph when Ceph nodes are collocated with
controllers, it is necessary to take a backup of the /var/lib/ceph
directory just before doing a recovery, restore the ReaR backup and then
extract the /var/lib/ceph backup over the (old) ceph data that is
outdated. With this simple action, the information lost is almost none.

This change creates two new scripts that are executed by ReaR during
restore that do exactly what is needed, eliminating the need for doing
it by hand.

Change-Id: Ib7c699b737980c5495cce2cf42f5847fda0f72f5

tripleo_ansible/roles/backup_and_restore/defaults/main.yml

@@ -112,3 +112,8 @@ tripleo_backup_and_restore_ceph_mon_role: "ceph_mon"
 
 # The cephadm path
 tripleo_backup_and_restore_cephadm_path: "/usr/sbin/cephadm"
+
+# Configure /var/lib/ceph automatic backuping and restoration during a recovery
+tripleo_backup_and_restore_ceph_device: /dev/vda2
+tripleo_backup_and_restore_ceph_device_format: xfs
+

tripleo_ansible/roles/backup_and_restore/tasks/setup_rear.yml

@@ -141,3 +141,32 @@
   when: sftp_backup
   tags:
     - bar_setup_rear
+
+- name: Program a script that will trigger during restore backuping /var/lib/ceph if it exists just before restore
+  blockinfile:
+    path: /usr/share/rear/setup/default/011_backup_ceph.sh
+    block: |
+      set -e
+      echo "Taking a fresh ceph data backup if this controller has co-located cephs"
+      mount -t {{ tripleo_backup_and_restore_ceph_device_format }} {{ tripleo_backup_and_restore_ceph_device }} /mnt/local
+      cd /mnt/local
+      [ -d "var/lib/ceph" ] && tar cvfz /tmp/ceph.tar.gz var/lib/ceph --xattrs --xattrs-include='*.*' --acls
+      cd /
+      umount {{ tripleo_backup_and_restore_ceph_device }}
+    create: yes
+  tags:
+    - bar_setup_rear
+
+- name: Program a script that will trigger during retoration to restore /var/lib/ceph backup after a full recovery
+  blockinfile:
+    path: /usr/share/rear/wrapup/default/501_restore_ceph.sh
+    block: |
+      set -e
+      echo "Restoring ceph backup if it exists"
+      if [ -f "/tmp/ceph.tar.gz" ]; then
+        rm -rf /mnt/local/var/lib/ceph/*
+        tar xvC /mnt/local -f /tmp/ceph.tar.gz var/lib/ceph --xattrs --xattrs-include='*.*'
+      fi
+    create: yes
+  tags:
+    - bar_setup_rear