[prometheus] Add memcached_exporter.

This patch adds the prometheus_memcached_exporter[0] to the
list of  available exporters, following the conventions
used by the previously integrated exporters.

[0] https://github.com/openstack/kolla/tree/master/docker/prometheus-memcached-exporter

Change-Id: I103b0ee19ef2fd17ce19a27d60773675ad234c1c
Closes-Bug: #1773303
Signed-off-by: Jorge Niedbalski <jorge.niedbalski@linaro.org>

ansible/group_vars/all.yml

@@ -272,6 +272,7 @@ prometheus_port: "9091"
 prometheus_node_exporter_port: "9100"
 prometheus_mysqld_exporter_port: "9104"
 prometheus_haproxy_exporter_port: "9101"
+prometheus_memcached_exporter_port: "9150"
 
 qdrouterd_port: "31459"
 
@@ -801,3 +802,4 @@ use_common_mariadb_user: "no"
 enable_prometheus_haproxy_exporter: "{{ enable_haproxy | bool }}"
 enable_prometheus_mysqld_exporter: "{{ enable_mariadb | bool }}"
 enable_prometheus_node_exporter: "yes"
+enable_prometheus_memcached_exporter: "{{ enable_memcached | bool }}"

ansible/inventory/all-in-one

@@ -668,3 +668,6 @@ mariadb
 
 [prometheus-haproxy-exporter:children]
 haproxy
+
+[prometheus-memcached-exporter:children]
+memcached

ansible/inventory/multinode

@@ -687,3 +687,6 @@ mariadb
 
 [prometheus-haproxy-exporter:children]
 haproxy
+
+[prometheus-memcached-exporter:children]
+memcached

ansible/roles/prometheus/defaults/main.yml

@@ -43,6 +43,15 @@ prometheus_services:
       - "/etc/localtime:/etc/localtime:ro"
       - "kolla_logs:/var/log/kolla/"
       - "haproxy_socket:/var/lib/kolla/haproxy"
+  prometheus-memcached-exporter:
+    container_name: prometheus_memcached_exporter
+    group: prometheus-memcached-exporter
+    enabled: "{{ enable_prometheus_memcached_exporter | bool }}"
+    image: "{{ prometheus_memcached_exporter_image_full }}"
+    volumes:
+      - "{{ node_config_directory }}/prometheus-memcached-exporter/:{{ container_config_directory }}/:ro"
+      - "/etc/localtime:/etc/localtime:ro"
+      - "kolla_logs:/var/log/kolla/"
 
 ####################
 # Database
@@ -70,3 +79,7 @@ prometheus_mysqld_exporter_image_full: "{{ prometheus_mysqld_exporter_image }}:{
 prometheus_node_exporter_image: "{{ docker_registry ~ '/' if docker_registry else '' }}{{ docker_namespace }}/{{ kolla_base_distro }}-{{ prometheus_install_type }}-prometheus-node-exporter"
 prometheus_node_exporter_tag: "{{ prometheus_tag }}"
 prometheus_node_exporter_image_full: "{{ prometheus_node_exporter_image }}:{{ prometheus_node_exporter_tag }}"
+
+prometheus_memcached_exporter_image: "{{ docker_registry ~ '/' if docker_registry else '' }}{{ docker_namespace }}/{{ kolla_base_distro }}-{{ prometheus_install_type }}-prometheus-memcached-exporter"
+prometheus_memcached_exporter_tag: "{{ prometheus_tag }}"
+prometheus_memcached_exporter_image_full: "{{ prometheus_memcached_exporter_image }}:{{ prometheus_memcached_exporter_tag }}"

ansible/roles/prometheus/handlers/main.yml

@@ -77,3 +77,22 @@
     - service.enabled | bool
     - config_json.changed | bool
       or prometheus_container.changed | bool
+
+- name: Restart prometheus-memcached-exporter container
+  vars:
+    service_name: "prometheus-memcached-exporter"
+    service: "{{ prometheus_services[service_name] }}"
+    config_json: "{{ prometheus_config_jsons.results|selectattr('item.key', 'equalto', service_name)|first }}"
+    prometheus_container: "{{ check_prometheus_containers.results|selectattr('item.key', 'equalto', service_name)|first }}"
+  kolla_docker:
+    action: "recreate_or_restart_container"
+    common_options: "{{ docker_common_options }}"
+    name: "{{ service.container_name }}"
+    image: "{{ service.image }}"
+    volumes: "{{ service.volumes }}"
+  when:
+    - kolla_action != "config"
+    - inventory_hostname in groups[service.group]
+    - service.enabled | bool
+    - config_json.changed | bool
+      or prometheus_container.changed | bool

ansible/roles/prometheus/tasks/precheck.yml

@@ -54,3 +54,15 @@
     - container_facts['prometheus_mysqld_exporter'] is not defined
     - inventory_hostname in groups['prometheus-haproxy-exporter']
     - enable_prometheus_haproxy_exporter | bool
+
+- name: Checking free port for Prometheus memcached_exporter
+  wait_for:
+    host: "{{ hostvars[inventory_hostname]['ansible_' + api_interface]['ipv4']['address'] }}"
+    port: "{{ prometheus_memcached_exporter_port }}"
+    connect_timeout: 1
+    timeout: 1
+    state: stopped
+  when:
+    - container_facts['prometheus_memcached_exporter'] is not defined
+    - inventory_hostname in groups['prometheus-memcached-exporter']
+    - enable_prometheus_memcached_exporter | bool

ansible/roles/prometheus/templates/prometheus-memcached-exporter.json.j2

@@ -0,0 +1,11 @@
+{
+    "command": "/opt/memcached_exporter/memcached_exporter --web.listen-address {{ api_interface_address }}:{{ prometheus_memcached_exporter_port }} --memcached.address {{ api_interface_address }}:{{ memcached_port }}",
+    "config_files": [],
+    "permissions": [
+        {
+            "path": "/var/log/kolla/prometheus",
+            "owner": "prometheus:kolla",
+            "recurse": true
+        }
+    ]
+}

ansible/roles/prometheus/templates/prometheus.yml.j2

@@ -39,3 +39,12 @@ scrape_configs:
         - '{{ hostvars[host]['ansible_' + hostvars[host]['api_interface']]['ipv4']['address'] }}:{{ hostvars[host]['prometheus_haproxy_exporter_port'] }}'
 {% endfor %}
 {% endif %}
+
+{% if enable_prometheus_memcached_exporter | bool %}
+  - job_name: memcached
+    static_configs:
+      - targets:
+{% for host in groups['prometheus-memcached-exporter'] %}
+        - '{{ hostvars[host]['ansible_' + hostvars[host]['api_interface']]['ipv4']['address'] }}:{{ hostvars[host]['prometheus_memcached_exporter_port'] }}'
+{% endfor %}
+{% endif %}