Getting started

debops.postgresql role is only the client part. For a working PostgreSQL installation, debops.postgresql_server also needs to run somewhere. It can be either on the same host, or on a separate one.

See the debops.postgresql_server documentation to learn how to install the database server itself.

The PostgreSQL version installed by the role will be a default version offered by the distribution. If you want PostgreSQL 9.4 on Debian Wheezy, or an upstream version of the server, you can enable the upstream APT repository by adding in inventory:

postgresql__upstream: True

Check postgresql__preferred_version to learn more about selecting custom PostgreSQL versions.

Server configuration

The role supports different modes of operation, depending on the presence of a PostgreSQL server installed locally or not.

Local database server

If the database server is installed locally, it will be automatically detected and used by the debops.postgresql role without any additional configuration.

If a remote server was used previously, and then a local one was installed, it will automatically override the remote configuration. You might need to recreate the databases and user accounts in that case.

Remote database server

If your PostgreSQL server is configured on a remote host and debops.postgresql does not detect a local installation, it won't manage databases or user accounts without a server specified.

To point it to a server, you need to set a variable in the inventory:

postgresql__server: 'db.example.org'

This needs to be a FQDN address or an IP address of a host with the PostgreSQL server installed. This host will be accessed by Ansible using task delegation, so it needs to be accessible and managed by Ansible. Currently the role only supports one server at a time.

If you use debops.pki to manage SSL certificates and you configured PostgreSQL server with them, remote connections to the database will be automatically encrypted. The default server configuration requires remote connections to be done over SSL, otherwise the connection is dropped.

Example inventory

To enable PostgreSQL client support on a host, you need to add that host to [debops_service_postgresql] Ansible group:

[debops_service_postgresql] hostname

When PostgreSQL server is properly configured, or installed locally, you can create user accounts and databases using inventory variables:

postgresql__roles:

  - name: 'application'

  - name: 'application_production'
    flags: [ 'NOLOGIN' ]

postgresql__databases:

  - database: 'application_production'
    owner:    'application_production'

postgresql__groups:

  - roles:  [ 'application' ]
    groups: [ 'application_production' ]
    database: 'application_production'

postgresql__pgpass:

  - owner: 'application'

The above set of variables will create the PostgreSQL roles application and application_production, which is meant to manage the database and cannot directly be logged into.

The application_production PostgreSQL database will be created on the server and the application_production role will be its owner.

The application role will be granted access to the application_production role and all of its objects.

Next, Ansible will ensure that the local system group and user account application exists, and will create ~/.pgpass with PostgreSQL user and password stored for easier access.

Example playbook

Here's an example Ansible playbook that uses the debops.postgresql role:

---

- name: Manage PostgreSQL client
  collections: [ 'debops.debops', 'debops.roles01',
                 'debops.roles02', 'debops.roles03' ]
  hosts: [ 'debops_service_postgresql' ]
  become: True

  environment: '{{ inventory__environment | d({})
                   | combine(inventory__group_environment | d({}))
                   | combine(inventory__host_environment  | d({})) }}'

  roles:

    - role: keyring
      tags: [ 'role::keyring', 'skip::keyring', 'role::postgresql' ]
      keyring__dependent_apt_keys:
        - '{{ postgresql__keyring__dependent_apt_keys }}'

    - role: apt_preferences
      tags: [ 'role::apt_preferences', 'skip::apt_preferences' ]
      apt_preferences__dependent_list:
        - '{{ postgresql__apt_preferences__dependent_list }}'

    - role: python
      tags: [ 'role::python', 'skip::python', 'role::postgresql' ]
      python__dependent_packages3:
        - '{{ postgresql__python__dependent_packages3 }}'
      python__dependent_packages2:
        - '{{ postgresql__python__dependent_packages2 }}'

    - role: postgresql
      tags: [ 'role::postgresql', 'skip::postgresql' ]

Local Ansible facts, custom tasks

Role creates a set of local Ansible facts which can be used by other roles to create database management tasks that work both with local and remote PostgreSQL servers. These facts are:

• ansible_local.postgresql.delegate_to
• ansible_local.postgresql.server
• ansible_local.postgresql.port
• ansible_local.postgresql.user
• ansible_local.postgresql.version

These variables can be used in Ansible tasks to provide correct values pointing to the correct PostgreSQL server. An example set of tasks to create a role and database:

- name: Create database role
  postgresql_user:
    name: '{{ application_database_user }}'
    password: '{{ application_database_password }}'
    state: 'present'
  delegate_to: '{{ ansible_local.postgresql.delegate_to }}'

- name: Create application database
  postgresql_db:
    name: '{{ application_database_name }}'
    owner: '{{ application_database_user }}'
    state: 'present'
  delegate_to: '{{ ansible_local.postgresql.delegate_to }}'
  register: application_register_database