Manage the prometheus exporter.

defaults/main.yml

@@ -82,5 +82,24 @@ mongodb_authorization_enabled: False
 mongodb_replicaset: storagedev
 mongodb_replica_keyfile: '{{ mongodb_dbpath }}/replica_keyfile'
 
-# User and password are stored in the variables mongo_monitoring_u and mongo_monitoring_pwd
-
+# Prometheus metrics
+mongodb_prometheus_exporter_enabled: False
+mongodb_prometheus_exporter_version: '0.30.0'
+mongodb_prometheus_exporter_dir: 'mongodb_exporter-{{ mongodb_prometheus_exporter_version }}.linux-amd64'
+mongodb_prometheus_exporter_file: '{{ mongodb_prometheus_exporter_dir }}.tar.gz'
+mongodb_prometheus_exporter_url: 'https://github.com/percona/mongodb_exporter/releases/download/v{{ mongodb_prometheus_exporter_version }}/{{ mongodb_prometheus_exporter_file }}'
+mongodb_prometheus_exporter_port: 9216
+mongodb_prometheus_exporter_loglevel: error
+mongodb_prometheus_exporter_opts: '--web.listen-address=":{{ mongodb_prometheus_exporter_port }}" --log.level={{ mongodb_prometheus_exporter_loglevel }}'
+mongodb_prometheus_exporter_connection_opts: '--mongodb.uri="mongodb://{{ mongodb_prometheus_exporter_connection_user }}:{{ mongodb_prometheus_exporter_connection_password }}@{{ mongodb_prometheus_exporter_connection_host }}/{{ mongodb_prometheus_exporter_connection_params }}"'
+mongodb_prometheus_exporter_collect_opts: '--mongodb.global-conn-pool --mongodb.direct-connect=true --collector.topmetrics --discovering-mode --collector.dbstats'
+# List the additional options here
+mongodb_prometheus_exporter_additional_opts: ''
+mongodb_prometheus_exporter_user: prometheus_mongodb
+mongodb_prometheus_exporter_home: '/opt/{{ mongodb_prometheus_exporter_user }}'
+mongodb_prometheus_exporter_dist_dir: '{{ prometheus_n_e_home }}/dist'
+mongodb_prometheus_exporter_cmd: '{{ mongodb_prometheus_exporter_dist_dir }}/{{ mongodb_prometheus_exporter_dir }}/mongodb_exporter'
+mongodb_prometheus_exporter_connection_host: 'localhost:27017'
+mongodb_prometheus_exporter_connection_user: monitor
+#mongodb_prometheus_exporter_connection_password: 'use a vault'
+mongodb_prometheus_exporter_connection_params: 'admin?ssl=true'

handlers/main.yml

@@ -7,3 +7,11 @@
   service: name=mongodb state=restarted
   when: "'{{ mongodb_start_server }}' == 'yes'"
 
+- name: Restart mongodb exporter
+  ansible.builtin.service:
+    name: mongodb_exporter
+    state: restarted
+
+- name: Reload the systemd data
+  systemd:
+    daemon_reload: yes

tasks/main.yml

@@ -2,3 +2,4 @@
 - import_tasks: mongodb.yml
 - import_tasks: mongodb-letsencrypt-acmetool.yml
   when: mongodb_ssl_letsencrypt_managed
+- import_tasks: mongodb-prometheus-exporter.yml

tasks/mongodb-prometheus-exporter.yml

@@ -0,0 +1,80 @@
+---
+- name: Mongodb exporter
+  block:
+    - name: Create the user under the mongodb exporter will run
+      ansible.builtin.user:
+        name: '{{ mongodb_prometheus_exporter_user }}'
+        home: '{{ mongodb_prometheus_exporter_home }}'
+        createhome: no
+        shell: /usr/sbin/nologin
+        system: yes
+
+    - name: Create the prometheus mongodb exporter base directory
+      ansible.builtin.file:
+        dest: '{{ item }}'
+        state: directory
+        owner: root
+        group: root
+      loop:
+        - '{{ mongodb_prometheus_exporter_home }}'
+        - '{{ mongodb_prometheus_exporter_dist_dir }}'
+
+    - name: Download the prometheus mongodb exporter
+      ansible.builtin.get_url:
+        url: '{{ mongodb_prometheus_exporter_download_url }}'
+        dest: /srv/
+
+    - name: Unarchive the prometheus distribution
+      ansible.builtin.unarchive:
+        src: '/srv/{{ mongodb_prometheus_exporter_file }}'
+        dest: '{{ mongodb_prometheus_exporter_dist_dir }}'
+        remote_src: yes
+        owner: root
+        group: root
+      args:
+        creates: '{{ mongodb_prometheus_exporter_dist_dir }}/{{ mongodb_prometheus_exporter_dir }}/mongodb_exporter'
+      notify: Restart mongodb exporter
+
+    - name: Install the prometheus node exporter upstart script
+      ansible.builtin.template:
+        src: mongodb_exporter.upstart.j2
+        dest: /etc/init/mongodb_exporter.conf
+        mode: 0644
+        owner: root
+        group: root
+      when: ansible_service_mgr != 'systemd'
+      notify: Restart mongodb exporter
+
+    - name: Install the prometheus mongodb exporter systemd unit
+      ansible.builtin.template:
+        src: mongodb_exporter.service.j2
+        dest: /etc/systemd/system/mongodb_exporter.service
+        mode: 0644
+        owner: root
+        group: root
+      when: ansible_service_mgr == 'systemd'
+      notify:
+        - Reload the systemd data
+        - Restart mongodb exporter
+
+    - ansible.builtin.meta: flush_handlers
+
+    - name: Ensure that prometheus mongodb_exporter is started and enabled
+      ansible.builtin.service:
+        name: mongodb_exporter
+        state: started
+        enabled: yes
+
+  when: mongodb_prometheus_exporter_enabled
+  tags: [ 'mongodb', 'prometheus', 'mongodb_prometheus' ]
+
+- name: No mongodb exporter
+  block:
+  - name: Ensure that prometheus mongodb_exporter is stopped and disabled
+    ansible.builtin.service:
+      name: mongodb_exporter
+      state: stopped
+      enabled: no
+
+  when: not mongodb_prometheus_exporter_enabled
+  tags: [ 'mongodb', 'prometheus', 'mongodb_prometheus' ]

templates/mongodb_exporter.service.j2

@@ -0,0 +1,15 @@
+[Unit]
+Description=mongodb_exporter - Prometheus exporter for mongodb.
+After=network.target
+
+[Service]
+Type=simple
+Restart=on-failure
+
+User={{ mongodb_prometheus_exporter_user }}
+Group={{ mongodb_prometheus_exporter_user }}
+
+ExecStart={{ mongodb_prometheus_exporter_cmd }} {{ mongodb_prometheus_exporter_opts }} {{ mongodb_prometheus_exporter_additional_opts }} {{ mongodb_prometheus_exporter_collect_opts }} {{ mongodb_prometheus_exporter_connection_opts }}
+
+[Install]
+WantedBy=multi-user.target

templates/mongodb_exporter.upstart.j2

@@ -0,0 +1,12 @@
+description "Prometheus mongodb exporter"
+start on (local-filesystems and net-device-up IFACE!=lo)
+stop on runlevel [016]
+
+respawn
+respawn limit 10 5
+setuid {{ mongodb_prometheus_exporter_user }}
+setgid {{ mongodb_prometheus_exporter_user }}
+
+script
+  exec {{ mongodb_prometheus_exporter_cmd }} {{ mongodb_prometheus_exporter_opts }} {{ mongodb_prometheus_exporter_connection_opts }} {{ mongodb_prometheus_exporter_additional_opts }} > {{ mongodb_prometheus_exporter_logdir }}/mongodb_exporter.log 2>&1
+end script