ansible/roles/prometheus-node-exporter/tasks/main.yml

---
- name: Install Prometheus Node exporter
  apt:
    name:
      - prometheus-node-exporter
    state: latest
    update_cache: true
    install_recommends: false  # Do not install smartmontools
  register: apt_result
  retries: 3
  until: apt_result is succeeded

# TODO: add auth
#
# Create the file --web.config=/etc/node_exporter/config.yaml
# and add --web.config=/etc/node_exporter/config.yaml to 
# the args in /etc/default/prometheus-node-exporter

- name: Setup the arguments for node-exporter
  template:
    src: prometheus-node-exporter
    dest: /etc/default/prometheus-node-exporter
    owner: root
    group: root
    mode: '0644'
  notify: Restart prometheus-node-exporter
  vars:
    args:
      - name: web.listen-address
        value: "{{ lan_address }}:9100"
#      - name: web.config
#        value: /etc/node_exporter/config.yaml

# Add the node to the server targets

- name: Get the list of targets of the server
  slurp:
    src: /etc/prometheus/node-targets.json
  register: server_target_file
  delegate_to: "{{ appointed_prometheus_server }}"

- name: Set target variable
  set_fact:
    server_target: "{{ server_target_file['content'] | b64decode | from_json }}"

- name: Add the node to the targets
  set_fact:
    server_target: "[{{ server_target[0] | combine({'targets': [lan_address]}, list_merge='append_rp') }}]"

- name: Put the new target list
  copy:
    content: "{{ server_target | to_nice_json }}"
    dest: /etc/prometheus/node-targets.json
  delegate_to: "{{ appointed_prometheus_server }}"