examples/ansible-postgres/deploy_postgres.yaml

---
- name: Configure PostgreSQL master on Ubuntu 24
  hosts: master
  become: yes
  vars:
    postgres_version: 16
    replication_user: replicator
    replication_password: "your_password"
  tasks:
    - name: Install software-properties-common
      apt:
        name: software-properties-common
        state: present
        update_cache: yes

    - name: Add Universe repository on master
      command: add-apt-repository universe -y
      args:
        creates: /etc/apt/sources.list.d/universe.list
      register: add_universe_master
      changed_when: add_universe_master.stdout != ""

    - name: Update apt cache after adding Universe repository on master
      apt:
        update_cache: yes
      when: add_universe_master is changed

    - name: Install PostgreSQL 16 on master
      apt:
        name: "postgresql-{{ postgres_version }}"
        state: present

    - name: Install python3-psycopg2 for PostgreSQL modules on master
      apt:
        name: python3-psycopg2
        state: present

    - name: Ensure listen_addresses is removed (cleanup) in postgresql.conf
      lineinfile:
        path: "/etc/postgresql/{{ postgres_version }}/main/postgresql.conf"
        regexp: '^(#\s*)?listen_addresses'
        state: absent
      notify: Restart PostgreSQL

    - name: Set listen_addresses to '*' in postgresql.conf
      blockinfile:
        path: "/etc/postgresql/{{ postgres_version }}/main/postgresql.conf"
        marker: "# {mark} ANSIBLE MANAGED LISTEN ADDRESSES"
        block: |
          listen_addresses = '*'          
      notify: Restart PostgreSQL

    - name: Set wal_level to replica
      lineinfile:
        path: "/etc/postgresql/{{ postgres_version }}/main/postgresql.conf"
        regexp: '^(#\s*)?wal_level'
        line: "wal_level = replica"
      notify: Restart PostgreSQL

    - name: Set max_wal_senders to 3
      lineinfile:
        path: "/etc/postgresql/{{ postgres_version }}/main/postgresql.conf"
        regexp: '^(#\s*)?max_wal_senders'
        line: "max_wal_senders = 3"
      notify: Restart PostgreSQL

    - name: Allow replication connections in pg_hba.conf on master
      lineinfile:
        path: "/etc/postgresql/{{ postgres_version }}/main/pg_hba.conf"
        line: "host replication {{ replication_user }} 0.0.0.0/0 md5"
        create: yes
      notify: Restart PostgreSQL

    - name: Create replication user on master
      postgresql_user:
        name: "{{ replication_user }}"
        password: "{{ replication_password }}"
        role_attr_flags: "REPLICATION"
        login_user: postgres
        state: present
      become_user: postgres

  handlers:
    - name: Restart PostgreSQL
      service:
        name: postgresql
        state: restarted

- name: Configure PostgreSQL replica on Ubuntu 24
  hosts: replica
  become: yes
  vars:
    postgres_version: 16
    replication_user: replicator
    replication_password: "your_password"
    master_ip: "{{ hostvars['master_host']['ansible_host'] | default('149.36.48.100') }}"
  tasks:
    - name: Install software-properties-common on replica
      apt:
        name: software-properties-common
        state: present
        update_cache: yes

    - name: Add Universe repository on replica
      command: add-apt-repository universe -y
      args:
        creates: /etc/apt/sources.list.d/universe.list
      register: add_universe_replica
      changed_when: add_universe_replica.stdout != ""

    - name: Update apt cache after adding Universe repository on replica
      apt:
        update_cache: yes
      when: add_universe_replica is changed

    - name: Install PostgreSQL 16 on replica
      apt:
        name: "postgresql-{{ postgres_version }}"
        state: present

    - name: Stop PostgreSQL service on replica
      service:
        name: postgresql
        state: stopped

    - name: Remove old PostgreSQL data directory on replica
      file:
        path: "/var/lib/postgresql/{{ postgres_version }}/main"
        state: absent

    - name: Use pg_basebackup to clone master data
      command: >
        pg_basebackup -h {{ master_ip }}
        -D /var/lib/postgresql/{{ postgres_version }}/main
        -U {{ replication_user }} -v -P --wal-method=stream        
      become_user: postgres
      environment:
        PGPASSWORD: "{{ replication_password }}"

    - name: Create standby.signal file (for PostgreSQL 12+)
      file:
        path: "/var/lib/postgresql/{{ postgres_version }}/main/standby.signal"
        state: touch

    - name: Set primary connection info for replica
      lineinfile:
        path: "/var/lib/postgresql/{{ postgres_version }}/main/postgresql.auto.conf"
        line: "primary_conninfo = 'host={{ master_ip }} port=5432 user={{ replication_user }} password={{ replication_password }}'"
      notify: Restart PostgreSQL

  handlers:
    - name: Restart PostgreSQL
      service:
        name: postgresql
        state: started