Add monitoring

Signed-off-by: Yohann D'ANELLO <ynerant@crans.org>

roles/prometheus/tasks/main.yml

@@ -0,0 +1,42 @@
+---
+- name: Install Prometheus
+  apt:
+    update_cache: true
+    name: prometheus
+  register: apt_result
+  retries: 3
+  until: apt_result is succeeded
+
+- name: Configure Prometheus
+  template:
+    src: prometheus/prometheus.yml.j2
+    dest: /etc/prometheus/prometheus.yml
+    mode: 0644
+  notify: Restart Prometheus
+
+- name: Configure Prometheus alert rules
+  template:
+    src: prometheus/alert.rules.yml.j2
+    dest: /etc/prometheus/alert.rules.yml
+    mode: 0644
+  notify: Restart Prometheus
+
+# We don't need to restart Prometheus when updating nodes
+- name: Configure Prometheus targets
+  copy:
+    content: "{{ [{'targets': item.value.targets}] | to_nice_json }}\n"
+    dest: "/etc/prometheus/{{ item.value.file }}"
+    mode: 0644
+  loop: "{{ prometheus | dict2items }}"
+
+- name: Activate prometheus service
+  systemd:
+    name: prometheus
+    enabled: true
+    state: started
+
+- name: Indicate role in motd
+  template:
+    src: update-motd.d/05-service.j2
+    dest: /etc/update-motd.d/05-prometheus
+    mode: 0755