Perform an atomic policy file change

The policy.json file is currently read continually by the
services and is not only read on service start. We therefore
cannot template directly to the file read by the service
(if the service is already running) because the new policies
may not be valid until the service restarts. This is
particularly important during a major upgrade. We therefore
only put the policy file in place after the service restart.

This patch also tidies up the handlers and some of the install
tasks to simplify them and reduce the tasks/code a little.

Change-Id: I706d99cec90491216bb997ed06cbed6514e1b663

handlers/main.yml

@@ -14,11 +14,54 @@
 # limitations under the License.
 
 - name: Restart ceilometer services
-  systemd:
+  debug:
+    msg: "Restarting services"
+  changed_when: true
+  notify:
+    - Stop services
+    - Copy new policy file into place
+    - Start services
+
+- name: Stop services
+  service:
     name: "{{ item.0.service_name }}"
-    state: "restarted"
-    daemon_reload: yes
+    enabled: yes
+    state: "stopped"
+    daemon_reload: "{{ (ansible_service_mgr == 'systemd') | ternary('yes', omit) }}"
   with_subelements:
     - "{{ ceilometer_services }}"
     - group
   when: inventory_hostname in groups[item.1]
+  register: _stop
+  until: _stop | success
+  retries: 5
+  delay: 2
+
+# Note (odyssey4me):
+# The policy.json file is currently read continually by the services
+# and is not only read on service start. We therefore cannot template
+# directly to the file read by the service because the new policies
+# may not be valid until the service restarts. This is particularly
+# important during a major upgrade. We therefore only put the policy
+# file in place after the service has been stopped.
+#
+- name: Copy new policy file into place
+  copy:
+    src: "/etc/ceilometer/policy.json-{{ ceilometer_venv_tag }}"
+    dest: "/etc/ceilometer/policy.json"
+    remote_src: yes
+
+- name: Start services
+  service:
+    name: "{{ item.0.service_name }}"
+    enabled: yes
+    state: "started"
+    daemon_reload: "{{ (ansible_service_mgr == 'systemd') | ternary('yes', omit) }}"
+  with_subelements:
+    - "{{ ceilometer_services }}"
+    - group
+  when: inventory_hostname in groups[item.1]
+  register: _start
+  until: _start | success
+  retries: 5
+  delay: 2

tasks/ceilometer_init_common.yml

@@ -1,29 +0,0 @@
----
-# Copyright 2016, Rackspace US, Inc.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-# http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-- include: ceilometer_init_systemd.yml
-  when:
-    - ansible_service_mgr == 'systemd'
-
-- name: Load service
-  service:
-    name: "{{ item.0.service_name }}"
-    state: "restarted"
-  with_subelements:
-    - "{{ ceilometer_services }}"
-    - group
-  when: inventory_hostname in groups[item.1]
-  notify:
-    - Restart ceilometer services

tasks/ceilometer_init_systemd.yml

@@ -60,6 +60,8 @@
     - "{{ ceilometer_services }}"
     - group
   when: inventory_hostname in groups[item.1]
+  notify:
+    - Restart ceilometer services
 
 - name: Place the systemd init script
   config_template:

tasks/ceilometer_post_install.yml

@@ -85,7 +85,7 @@
       list_extend: false
       path: "etc/ceilometer/examples/"
     - name: "policy.json"
-      dest: "/etc/ceilometer/policy.json"
+      dest: "/etc/ceilometer/policy.json-{{ ceilometer_venv_tag }}"
       config_overrides: "{{ ceilometer_policy_overrides }}"
       config_type: "json"
     - name: "polling.yaml"

tasks/main.yml

@@ -44,7 +44,7 @@
   tags:
     - ceilometer-config
 
-- include: ceilometer_init_common.yml
+- include: "ceilometer_init_{{ ansible_service_mgr }}.yml"
   tags:
     - ceilometer-config