setup-consul.yaml

- hosts: server
  vars:
    ansible_user: ubuntu
    inventory: hosts
  tasks:
  - name: Check server connection
    command: echo "Connection is ready"
    tags: ["check-ssh"]

  ## Update /etc/hosts
  - name: Add IP hostname pair in /etc/hosts
    lineinfile:
      dest: /etc/hosts
      state: present
      regex: "{{ hostvars[item].ansible_default_ipv4.address }} {{ item }}"
      line: "{{ hostvars[item].ansible_default_ipv4.address }} {{ item }}"
    with_items: "{{ groups['server'] }}"
  
  ## Install Consul by APT
  - name: Add Consul APT key
    apt_key:
      url: https://apt.releases.hashicorp.com/gpg
  - name: Add Consul APT repository
    apt_repository:
      repo: deb https://apt.releases.hashicorp.com focal main
  - name: Install Consul package
    package:
      name: consul  

  ## Update Consul config file /etc/consul.d/consul.hcl
  - name: Update Consul config, set server = true
    lineinfile:
      dest: /etc/consul.d/consul.hcl
      state: present
      regex: ".*server.*=.*"
      line: "server = true"
  - name: Update Consul config, set bootstrap_expect = 3
    lineinfile:
      dest: /etc/consul.d/consul.hcl
      state: present
      regex: ".*bootstrap_expect.*=.*"
      line: "bootstrap_expect = 3"
  - name: Update Consul config, set retry_join = [ALL_CONSUL_SERVERS]
    lineinfile:
      dest: /etc/consul.d/consul.hcl
      state: present
      regex: "^retry_join = .*"
      line: >-
        retry_join = ["{{ groups['server'] | join('", "')  }}"]
  - name: FIX Consul systemd service file
    # There is a pitfall on Ubuntu 20.04 .deb package
    # https://github.com/hashicorp/consul/issues/11911
    lineinfile:
      dest: /lib/systemd/system/consul.service
      state: present
      regex: "^EnvironmentFile=/etc/consul.d/consul.env"
      line: "EnvironmentFile=-/etc/consul.d/consul.env"
  
  ## Start Consul services in the cluster
  - name: Start Consul cluster
    systemd:
      name: consul
      state: started
      daemon_reload: yes

  ## Consul Web UI
  - name: Enable Consul Web UI
    command: 'echo "Enable Consul UI on {{ play_hosts[0] }}"'
    when: inventory_hostname == play_hosts[0]
    tags: ['consul-ui', 'never']
  - name: Update Consul config, set ui_config.enable = true
    replace:
      path: /etc/consul.d/consul.hcl
      backup: yes
      regexp: "#ui_config{\n#  enabled = true\n#}"
      replace: |
        ui_config {
          enabled = true
        }
    when: inventory_hostname == play_hosts[0]
    tags: ['consul-ui', 'never']
  - name: Restart Consul server
    systemd:
      name: consul
      state: restarted
      daemon_reload: yes
    when: inventory_hostname == play_hosts[0]
    tags: ['consul-ui', 'never']