From 505cded29b4f399a2dd9494409548a6fb7e4ccb8 Mon Sep 17 00:00:00 2001
From: Doug Szumski <doug@stackhpc.com>
Date: Fri, 20 Mar 2020 10:56:04 +0000
Subject: [PATCH] Support disabling Prometheus server

This is useful to people who manage their Prometheus Server
externally to Kolla Ansible, or want to use the exporters with
another framework such as Monasca.

Change-Id: Ie3f61e2e186c8e77e21a7b53d2bd7d2a27eee18e
---
 ansible/group_vars/all.yml                                  | 1 +
 ansible/roles/prometheus/defaults/main.yml                  | 4 ++--
 ansible/roles/prometheus/tasks/precheck.yml                 | 1 +
 etc/kolla/globals.yml                                       | 1 +
 ...upport-disabling-prometheus-server-907be6846bc364df.yaml | 6 ++++++
 5 files changed, 11 insertions(+), 2 deletions(-)
 create mode 100644 releasenotes/notes/support-disabling-prometheus-server-907be6846bc364df.yaml

diff --git a/ansible/group_vars/all.yml b/ansible/group_vars/all.yml
index d065f3bee8..ffefbf87aa 100644
--- a/ansible/group_vars/all.yml
+++ b/ansible/group_vars/all.yml
@@ -1013,6 +1013,7 @@ use_common_mariadb_user: "no"
 ############
 # Prometheus
 ############
+enable_prometheus_server: "{{ enable_prometheus | bool }}"
 enable_prometheus_haproxy_exporter: "{{ enable_haproxy | bool }}"
 enable_prometheus_mysqld_exporter: "{{ enable_mariadb | bool }}"
 enable_prometheus_node_exporter: "{{ enable_prometheus | bool }}"
diff --git a/ansible/roles/prometheus/defaults/main.yml b/ansible/roles/prometheus/defaults/main.yml
index ae6f29275a..5d462cced0 100644
--- a/ansible/roles/prometheus/defaults/main.yml
+++ b/ansible/roles/prometheus/defaults/main.yml
@@ -5,13 +5,13 @@ prometheus_services:
   prometheus-server:
     container_name: prometheus_server
     group: prometheus
-    enabled: true
+    enabled: "{{ enable_prometheus_server }}"
     image: "{{ prometheus_server_image_full }}"
     volumes: "{{ prometheus_server_default_volumes + prometheus_server_extra_volumes }}"
     dimensions: "{{ prometheus_server_dimensions }}"
     haproxy:
       prometheus_server:
-        enabled: "{{ enable_prometheus }}"
+        enabled: "{{ enable_prometheus_server }}"
         mode: "http"
         external: false
         port: "{{ prometheus_port }}"
diff --git a/ansible/roles/prometheus/tasks/precheck.yml b/ansible/roles/prometheus/tasks/precheck.yml
index 2b6c6c2d77..f214a537df 100644
--- a/ansible/roles/prometheus/tasks/precheck.yml
+++ b/ansible/roles/prometheus/tasks/precheck.yml
@@ -25,6 +25,7 @@
   when:
     - container_facts['prometheus_server'] is not defined
     - inventory_hostname in groups['prometheus']
+    - enable_prometheus_server | bool
 
 - name: Checking free port for Prometheus node_exporter
   wait_for:
diff --git a/etc/kolla/globals.yml b/etc/kolla/globals.yml
index 524edaa244..c31b9f39df 100644
--- a/etc/kolla/globals.yml
+++ b/etc/kolla/globals.yml
@@ -632,6 +632,7 @@
 ############
 # Prometheus
 ############
+#enable_prometheus_server: "{{ enable_prometheus | bool }}"
 #enable_prometheus_haproxy_exporter: "{{ enable_haproxy | bool }}"
 #enable_prometheus_mysqld_exporter: "{{ enable_mariadb | bool }}"
 #enable_prometheus_node_exporter: "{{ enable_prometheus | bool }}"
diff --git a/releasenotes/notes/support-disabling-prometheus-server-907be6846bc364df.yaml b/releasenotes/notes/support-disabling-prometheus-server-907be6846bc364df.yaml
new file mode 100644
index 0000000000..00bb4d163f
--- /dev/null
+++ b/releasenotes/notes/support-disabling-prometheus-server-907be6846bc364df.yaml
@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Prometheus server can now be disabled, allowing the exporters to be
+    deployed without it. The default behaviour of deploying Prometheus
+    server when Prometheus is enabled remains.