Implement data migrations for rolling upgrades

In order to cater for artifact-based installed, and
rolling upgrades, this patch implements a set of local
facts to inform the db sync and online migrations
tasks.

The 'cinder_all_software_updated' variables will be
set by the playbook on each run to ensure that the
online migrations only happen once all venvs are
homogenous. This ensures that the playbook can be
executed in a serialised fashion and the data will
not be corrupted.

Change-Id: I9aacda78f92355374af3f4ab24d2d9a9b47491ed

releasenotes/notes/cinder-data-migrations-ce31707c078b335c.yaml

@@ -0,0 +1,9 @@
+---
+features:
+  - The ``os_cinder`` role now provides for doing
+    online data migrations once the db sync has
+    been completed. The data migrations will not
+    be executed until the boolean variable
+    ``cinder_all_software_updated`` is true. This
+    variable will need to be set by the playbook
+    consuming the role.

tasks/cinder_db_setup.yml

@@ -17,4 +17,45 @@
   command: "{{ cinder_bin }}/cinder-manage db sync"
   become: yes
   become_user: "{{ cinder_system_user_name }}"
+  when:
+    - "ansible_local['openstack_ansible']['cinder']['need_db_sync'] | bool"
   changed_when: false
+  register: dbsync
+
+- name: Disable the db sync requirement
+  ini_file:
+    dest: "/etc/ansible/facts.d/openstack_ansible.fact"
+    section: cinder
+    option: need_db_sync
+    value: False
+  when:
+    - dbsync | succeeded
+
+- name: Record the need for online data migrations
+  ini_file:
+    dest: "/etc/ansible/facts.d/openstack_ansible.fact"
+    section: cinder
+    option: need_online_data_migrations
+    value: True
+  when:
+    - dbsync | succeeded
+
+- name: Perform online data migrations
+  command: "{{ cinder_bin }}/cinder-manage db online-data-migrations"
+  become: yes
+  become_user: "{{ cinder_system_user_name }}"
+  when:
+    - "(cinder_all_software_updated | default('no')) | bool"
+    - "ansible_local['openstack_ansible']['cinder']['need_online_data_migrations'] | bool"
+  changed_when: false
+  register: data_migrations
+
+- name: Disable the online migrations requirement
+  ini_file:
+    dest: "/etc/ansible/facts.d/openstack_ansible.fact"
+    section: cinder
+    option: need_online_data_migrations
+    value: False
+  when:
+    - data_migrations | succeeded
+

tasks/cinder_install.yml

@@ -112,6 +112,36 @@
     virtualenv-tools --update-path=auto --reinitialize {{ cinder_bin | dirname }}
   when: cinder_get_venv | changed
 
+- name: Record the need for a db sync
+  ini_file:
+    dest: "/etc/ansible/facts.d/openstack_ansible.fact"
+    section: cinder
+    option: need_db_sync
+    value: True
+  when: cinder_get_venv | changed or
+        cinder_venv_dir | changed or
+        install_packages | changed
+
+- name: Initialise the online data migration local fact
+  ini_file:
+    dest: "/etc/ansible/facts.d/openstack_ansible.fact"
+    section: cinder
+    option: need_online_data_migrations
+    value: False
+  when: cinder_get_venv | changed or
+        cinder_venv_dir | changed or
+        install_packages | changed
+
+- name: Record the need for a service restart
+  ini_file:
+    dest: "/etc/ansible/facts.d/openstack_ansible.fact"
+    section: cinder
+    option: need_service_restart
+    value: True
+  when: cinder_get_venv | changed or
+        cinder_venv_dir | changed or
+        install_packages | changed
+
 - name: Record the venv tag deployed
   ini_file:
     dest: "/etc/ansible/facts.d/openstack_ansible.fact"

tasks/main.yml

@@ -33,21 +33,28 @@
   tags:
     - cinder-install
 
+- name: refresh local facts
+  setup:
+    filter: ansible_local
+    gather_subset: "!all"
+  tags:
+    - cinder-config
+
 - include: cinder_post_install.yml
   tags:
     - cinder-config
 
 - include: cinder_db_setup.yml
   when:
-    - groups['cinder_all'] | length > 0
-    - inventory_hostname == groups['cinder_all'][0]
+    - groups['cinder_api'] | length > 0
+    - inventory_hostname == groups['cinder_api'][0]
   tags:
     - cinder-config
 
 - include: cinder_service_setup.yml
   when:
-    - groups['cinder_all'] | length > 0
-    - inventory_hostname == groups['cinder_all'][0]
+    - groups['cinder_api'] | length > 0
+    - inventory_hostname == groups['cinder_api'][0]
   tags:
     - cinder-config