Only sync glance database on major versions

Since Glance doesn't yet have rolling upgrades, nor is the tooling
idempotent, we avoid running the database operations during minor
upgrades to maintain uptime.

Major upgrades will still run the sync operations, and the database will
be synced if there is no existing database regardless of the type of
upgrade.

Change-Id: I4a4d8f23f05a16d25878340ede019be7ccdb7196

tasks/glance_db_setup.yml

@@ -13,14 +13,43 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-- name: Perform a Glance DB sync
-  command: "{{ glance_bin }}/glance-manage db_sync"
+- name: Check Glance DB version
+  command: "{{ glance_bin }}/glance-manage db version"
   become: yes
   become_user: "{{ glance_system_user_name }}"
+  register: db_version
   changed_when: false
 
-- name: Load glance metadata definitions
-  command: "{{ glance_bin }}/glance-manage db_load_metadefs {{ glance_etc_dir }}/metadefs"
+# We only set to minor here if the version_compare filter passes, and we make
+# sure that can't be accessed unless there's actually a '.' in the version.
+# Passing in 'major' or 'testing' to version_compare causes a Jinja error.
+- name: Determine whether a major or minor release was installed
+  set_fact:
+    upgrade_type: |-
+        {% set existing = glance_venv_tag %}
+        {% set upgrade_type = 'major' %}
+        {% if '.' in existing %}
+        {%  set existing_major = existing.split('.')[0] %}
+        {%  set venv_major = glance_venv_tag.split('.')[0] %}
+        {%  if existing_major != venv_major %}
+        {%    set upgrade_type = 'major' %}
+        {%  elif existing | version_compare(glance_venv_tag, '!=', strict=True) %}
+        {%    set upgrade_type = 'minor' %}
+        {%  endif %}
+        {% endif %}
+        {{ upgrade_type }}
+  delegate_to: localhost
+
+- name: Perform a Glance DB sync
+  command: "{{ glance_bin }}/glance-manage db sync"
+  changed_when: false
   become: yes
   become_user: "{{ glance_system_user_name }}"
+  when: upgrade_type == 'major' or db_version.stdout.startswith('Database is either not under migration control')
+
+- name: Load glance metadata definitions
+  command: "{{ glance_bin }}/glance-manage db load_metadefs"
   changed_when: false
+  become: yes
+  become_user: "{{ glance_system_user_name }}"
+  when: upgrade_type == 'major' or db_version.stdout.startswith('Database is either not under migration control')

tasks/main.yml

@@ -33,6 +33,13 @@
   tags:
     - glance-install
 
+- name: refresh local facts
+  setup:
+    filter: ansible_local
+    gather_subset: "!all"
+  tags:
+    - glance-config
+
 - include: glance_post_install.yml
   tags:
     - glance-config
@@ -42,12 +49,19 @@
     - glance-config
 
 - include: glance_db_setup.yml
-  when: inventory_hostname == groups['glance_all'][0]
+  run_once: true
   tags:
     - glance-config
 
 - include: glance_service_setup.yml
-  when: inventory_hostname == groups['glance_all'][0]
+  run_once: true
+  tags:
+    - glance-config
+
+- name: refresh local facts
+  setup:
+    filter: ansible_local
+    gather_subset: "!all"
   tags:
     - glance-config