Fix ceph role set target_max_bytes for cache pools

Ceph is not able to determine the size of a cache pool automatically,
so the configuration on the absolute size is required here
otherwise the flush/evict will not work.
see
http://docs.ceph.com/docs/master/rados/operations/cache-tiering/

Change-Id: I4d4abb50787093a292e1ee6eb790c10ecf5ccb94
Closes-Bug: #1654375

ansible/group_vars/all.yml

@@ -521,6 +521,12 @@ octavia_amp_flavor_id:
 # Ceph can be setup with a caching to improve performance. To use the cache you
 # must provide separate disks than those for the OSDs
 ceph_enable_cache: "no"
+
+# Ceph is not able to determine the size of a cache pool automatically,
+# so the configuration on the absolute size is required here, otherwise the flush/evict will not work.
+ceph_target_max_bytes: ""
+ceph_target_max_objects: ""
+
 # Valid options are [ forward, none, writeback ]
 ceph_cache_mode: "writeback"
 

ansible/roles/ceph_pools.yml

@@ -78,3 +78,23 @@
   failed_when: False
   run_once: True
   when: "{{ ceph_enable_cache | bool }}"
+
+- name: Setting cache target_max_bytes
+  command: docker exec ceph_mon ceph osd pool set {{ pool_name }}-cache target_max_bytes {{ ceph_target_max_bytes }}
+  delegate_to: "{{ groups['ceph-mon'][0] }}"
+  changed_when: False
+  failed_when: False
+  run_once: True
+  when:
+    - "{{ ceph_enable_cache | bool }}"
+    - "{{ ceph_target_max_bytes != '' }}"
+
+- name: Setting cache target_max_objects
+  command: docker exec ceph_mon ceph osd pool set {{ pool_name }}-cache target_max_objects {{ ceph_target_max_objects }}
+  delegate_to: "{{ groups['ceph-mon'][0] }}"
+  changed_when: False
+  failed_when: False
+  run_once: True
+  when:
+    - "{{ ceph_enable_cache | bool }}"
+    - "{{ ceph_target_max_objects != '' }}"

etc/kolla/globals.yml

@@ -200,6 +200,12 @@ kolla_internal_vip_address: "10.10.10.254"
 # Ceph can be setup with a caching to improve performance. To use the cache you
 # must provide separate disks than those for the OSDs
 #ceph_enable_cache: "no"
+
+# Ceph is not able to determine the size of a cache pool automatically,
+# so the configuration on the absolute size is required here, otherwise the flush/evict will not work.
+#ceph_target_max_bytes: ""
+#ceph_target_max_objects: ""
+
 # Valid options are [ forward, none, writeback ]
 #ceph_cache_mode: "writeback"