modified psql replication script from sam doran's role. Works with Tower 3.0.3 and RHEL 6.

psql-replication.yml

- name: Configure PostgreSQL streaming replication
  hosts: database_slave

  pre_tasks:
    - name: Remove recovery.conf
      file:
        path: /var/lib/pgsql/9.4/data/recovery.conf
        state: absent

    - name: Add slave to database group
      add_host:
        name: "{{ inventory_hostname }}"
        groups: database
      tags:
        - always

  roles:
    - role: packages_el
      packages_el_install_tower: false
      packages_el_install_postgres: true
      when: ansible_os_family == "RedHat"

    - role: postgres
      tags: postgresql_database
      postgres_allowed_ipv4: "0.0.0.0/0"
      postgres_allowed_ipv6: "::/0"
      postgres_username: "{{ pg_username }}"
      postgres_password: "{{ pg_password }}"
      postgres_database: "{{ pg_database }}"
      max_postgres_connections: 1024
      postgres_shared_memory_size: "{{ (ansible_memtotal_mb*0.3)|int }}"
      postgres_work_mem: "{{ (ansible_memtotal_mb*0.03)|int }}"
      postgres_maintenance_work_mem: "{{ (ansible_memtotal_mb*0.04)|int }}"


- name: Configure master server
  hosts: database[0]

  vars:
    postgresrep_master_address: "{{ hostvars[groups[postgresrep_group_name_master][0]].ansible_all_ipv4_addresses[0] }}"
    postgresrep_slave_address: "{{ hostvars[groups[postgresrep_group_name][0]].ansible_all_ipv4_addresses[0] }}"

  roles:
    - postgres-replication

- name: Configure slave server
  hosts: database_slave

  vars:
    postgresrep_master_address: "{{ hostvars[groups[postgresrep_group_name_master][0]].ansible_all_ipv4_addresses[0] }}"
    postgresrep_slave_address: "{{ hostvars[groups[postgresrep_group_name][0]].ansible_all_ipv4_addresses[0] }}"

  roles:
    - postgres-replication