Add way to periodically trim Cinder DB

We're adding a service that is responsible for executing db purge.
Service will be deployed by default, but left
stopped/disabled. This way we allow deployers to enable/disable
feature by changing value of cinder_purge_deleted.

Otherwise, when variables set to true once, setting them back to false
won't lead to stopping of DB trimming , so timer would need to be
stopped manually.

Change-Id: Ic5ae8c778bff2858fcb31c85d4b910805e452c3f

defaults/main.yml

@@ -459,3 +459,13 @@ cinder_pki_install_certificates:
 # Define user-provided SSL certificates
 #cinder_user_ssl_cert: <path to cert on ansible deployment host>
 #cinder_user_ssl_key: <path to cert on ansible deployment host>
+
+# Database cleanup
+# Periodically purge shadow tables, where archived records are stored
+cinder_purge_deleted: False
+# When to start purge task.
+cinder_purge_deleted_on_calendar: "*-*-* 01:00:00"
+# Purge events that are older then the number of days below.
+cinder_purge_deleted_before_days: "364"
+# Delay the timer by a randomly selected amount of time.
+cinder_purge_deleted_randomized_delay_sec: 0

releasenotes/notes/cinder_db_cleanup_service-4754f3094604f677.yaml

@@ -0,0 +1,12 @@
+---
+features:
+  - |
+    Added option to periodically clean-up deleted records from Cinder
+    database.
+    For this purpose a new service``cinder-purge-deleted`` was introduced.
+    It will be called periodically using corresponsive systemd timer on the
+    first cinder-api host.
+
+    By default this service is disabled/stopped and database cleanup
+    is not performed. You can enable this behaviour by defining variable
+    ``cinder_purge_deleted``.

tasks/main.yml

@@ -248,3 +248,34 @@
     - "_cinder_is_last_play_host"
   tags:
     - cinder-config
+
+- name: Create service and timer for archiving deleted records
+  include_role:
+    name: systemd_service
+  vars:
+    systemd_service_restart_changed: false
+    systemd_user_name: "{{ cinder_system_user_name }}"
+    systemd_group_name: "{{ cinder_system_group_name }}"
+    systemd_tempd_prefix: openstack
+    systemd_slice_name: "{{ cinder_system_slice_name }}"
+    systemd_lock_dir: "{{ cinder_lock_dir }}"
+    systemd_services:
+      - service_name: "cinder-purge-deleted"
+        execstarts:
+          - "{{ cinder_bin }}/cinder-manage db purge {{ cinder_purge_deleted_before_days }}"
+        environment:
+          UMASK: '0640'
+          UMASK_DIR: '0750'
+        program_sandboxing:
+          RuntimeDirectory: 'cinder-purge-deleted'
+        enabled: "{{ cinder_purge_deleted }}"
+        timer:
+          state: "{{ cinder_purge_deleted | ternary('started', 'stopped') }}"
+          enabled: "{{ cinder_purge_deleted }}"
+          options:
+            OnCalendar: "{{ cinder_purge_deleted_on_calendar }}"
+            RandomizedDelaySec: "{{ cinder_purge_deleted_randomized_delay_sec }}"
+            Persistent: true
+            Unit: "cinder-purge-deleted.service"
+  when:
+    - inventory_hostname == groups[cinder_services['cinder-api']['group']] | first