library/roles/prometheus-node-exporter: Role that installs and runs the prometheus node exporter.

prometheus-node-exporter/defaults/main.yml

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+---
+prometheus_n_e_install: True
+prometheus_n_e_version: 0.15.2
+prometheus_n_e_dir: 'node_exporter-{{ prometheus_n_e_version }}.linux-amd64'
+prometheus_n_e_file: '{{ prometheus_n_e_dir }}.tar.gz'
+prometheus_n_e_download_url: 'https://github.com/prometheus/prometheus/releases/download/v{{ prometheus_n_e_version }}/{{ prometheus_n_e_file }}'
+prometheus_n_e_user: prometheus
+prometheus_n_e_home: /opt/prometheus
+prometheus_n_e_dist_dir: '{{ prometheus_n_e_home }}/dist'
+prometheus_n_e_logdir: '/var/log/prometheus-node-exporter'
+prometheus_n_e_cmd: '{{ prometheus_n_e_dist_dir }}/{{ prometheus_n_e_dir }}/node_exporter'
+prometheus_n_e_port: 9100
+prometheus_n_e_loglevel: info
+prometheus_n_e_opts: '--web.listen-address=":{{ prometheus_n_e_port }} --log.level={{ prometheus_n_e_loglevel }}'
+# List the additional options here
+prometheus_n_e_additional_opts: ''

prometheus-node-exporter/handlers/main.yml

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+---
+- name: systemd reload
+  command: systemctl daemon-reload

prometheus-node-exporter/tasks/main.yml

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+---
+- block:
+    - name: Create the user under the node exporter will run
+      user: name={{ prometheus_n_e_user }} home={{ prometheus_n_e_home }} createhome=no shell=/usr/sbin/nologin system=yes
+
+    - name: Create the prometheus node exporter base directory
+      file: dest={{ item }} state=directory owner=root group=root
+      with_items:
+        - '{{ prometheus_n_e_home }}'
+        - '{{ prometheus_n_e_dist_dir }}'
+
+    - name: Create the prometheus node exporter log directory
+      file: dest={{ prometheus_n_e_logdir }} state=directory owner={{ prometheus_n_e_user }} group={{ prometheus_n_e_user }}
+
+    - name: Download the prometheus node exporter
+      get_url: url={{ prometheus_n_e_download_url }} dest=/srv/
+
+    - name: Unarchive the prometheus distribution
+      unarchive: src=/srv/{{ prometheus_n_e_file }} dest={{ prometheus_n_e_dist_dir }} remote_src=yes 
+      args:
+        creates: '{{ prometheus_n_e_dist_dir }}/{{ prometheus_n_e_dir }}/node_exporter'
+      notify: Restart node exporter
+
+    - name: Install the prometheus node exporter upstart script
+      template: src=node_exporter.upstart.j2 dest=/etc/init/node_exporter.conf mode=0644 owner=root group=root
+      when: ansible_service_mgr != 'systemd'
+
+    - name: Install the prometheus node exporter systemd unit
+      template: src=node_exporter.systemd.j2 dest=/etc/systemd/system/node_exporter.service mode=0644 owner=root group=root
+      when: ansible_service_mgr == 'systemd'
+      notify: systemd reload
+
+    - name: Ensure that prometheus node_exporter is started and enabled
+      service: name=node_exporter state=started enabled=yes
+
+  tags: [ 'prometheus', 'node_exporter' ]
+  when: prometheus_n_e_install
+
+- block:
+    - name: Ensure that prometheus node_exporter is stopped and disabled
+      service: name=node_exporter state=stopped enabled=no
+
+    - name: Remove prometheus node exporter upstart script
+      file: dest=/etc/init/node_exporter.conf state=absent
+      when: ansible_service_mgr != 'systemd'
+
+    - name: Remove the prometheus node exporter systemd unit
+      file: dest=/etc/systemd/system/node_exporter.service state=absent
+      when: ansible_service_mgr == 'systemd'
+      notify: systemd reload
+
+  tags: [ 'prometheus', 'node_exporter' ]
+  when: not prometheus_n_e_install

prometheus-node-exporter/templates/node_exporter.systemd.j2

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+[Unit]
+Description=node_exporter - Prometheus exporter for machine metrics.
+After=network.target
+
+[Service]
+Type=simple
+
+User={{ prometheus_user }}
+Group={{ prometheus_user }}
+
+ExecStart={{ prometheus_n_e_cmd }}  {{ prometheus_n_e_opts }} {{ prometheus_n_e_additional_opts }} --collector.systemd
+

prometheus-node-exporter/templates/node_exporter.upstart.j2

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+description "Prometheus node exporter"
+start on (local-filesystems and net-device-up IFACE!=lo)
+stop on runlevel [016]
+
+respawn
+respawn limit 10 5
+setuid {{ prometheus_n_e_user }}
+setgid {{ prometheus_n_e_user }}
+
+script
+  exec {{ prometheus_n_e_cmd }}  {{ prometheus_n_e_opts }} {{ prometheus_n_e_additional_opts }} > {{ prometheus_n_e_logdir }}/node_exporter.log 2>&1
+end script