Ansible Role: WAL-G

Ansible role to setup WAL-G PostgreSQL backup tool.

This role does not handle PostgreSQL installation. You may want to use this role in combination with another role to install PostgreSQL. See Example Playbook section for primer of variables substitution from geerlingguy.postgresql. PostgreSQL does not need to be installed on target host as long as you disable all PostgreSQL configuration tasks (see Role Variables section).

WAL-G have changed release binaries name scheme since 1.0, which is for now unsupported by this role. You can force installation by setting walg_binary_name and walg_download_url to tarball URL and exact file name.

Requirements

Python, Ansible >= 2.9

Role Variables

Variable	Deafule value	Description
walg_version	0.2.19	WAL-G version to download
walg_binary_dir	/usr/local/bin	Path to directory containing WAL-G binary
walg_conf	-	Dictionary containing WAL-G configuration parameters. See WAL-G documentation for available parameters
walg_configure_logrotate	True	Whether to configure WAL-G logs rotation. Logrotate should be installed
walg_logs_dir	/var/log/wal-g	Path to logs directory
walg_user	postgres	WAL-G owner (should be same with Postgres process owner)
walg_group	postgres	WAL-G group (should be same with Postgres process group)
walg_pg_data_dir	distro-specific	Path to PostgreSQL PGDATA directory
walg_configure_pg_settings	True	Wheteher to apply settings to PostreSQL global configuration (need restarting)
walg_wal_archive_timeout	3600	Value of wal_archive_timeout PostgreSQL configuration option
walg_pg_config_path	distro-specific	Path to directory containing PostgreSQL
walg_pg_service	distro-specific	PostgreSQL service name in distro init system
walg_pg_global_config_options	-	List of dictionaries containing global PostgreSQL configuration options
walg_pg_global_config_options[*].option	-	Configuration option name
walg_pg_global_config_options[*].value	-	Configuration option value
walg_configure_crontab	True	Whether to configure Cron jobs. Cron should be installed
walg_backup_cmd	{{ walg_binary_dir }}/{{ walg_binary_name }} backup-push {{ walg_pg_data_dir }} >> {{ walg_logs_dir }}/backup-push.log 2>&1	Cron backup command
walg_prune_cmd	{{ walg_binary_dir }}/{{ walg_binary_name }} delete retain FULL 12 >> {{ walg_logs_dir }}/delete.log 2>&1	Cron prune command
walg_backup_cron_minute	30	Cron backup job minutes field
walg_backup_cron_hour	0	Cron backup job hour field
walg_backup_cron_day	*	Cron backup job day field
walg_backup_cron_month	*	Cron backup job month field
walg_backup_cron_weekday	*	Cron backup job weekday field
walg_prune_cron_minute	0	Cron prune job minutes field
walg_prune_cron_hour	6	Cron prune job hour field
walg_prune_cron_day	*	Cron prune job day field
walg_prune_cron_month	*	Cron prune job month field
walg_prune_cron_weekday	*	Cron prune job weekday field
walg_cron_jobs	x	List of dictionaries describing custom Cron jobs to configure (overrides walg_*_cron_* values)
walg_cron_jobs[*].name	-	Cron job name
walg_cron_jobs[*].minute	*	Cron job minutes field
walg_cron_jobs[*].day	*	Cron job day field
walg_cron_jobs[*].month	*	Cron job month field
walg_cron_jobs[*].weekday	*	Cron job weekday field
walg_cron_jobs[*].job	*	Cron job command

Dependencies

None.

Supported platforms

• RHEL 7, 8

NB1: RHEL 7 official repo contains PostgreSQL 9.2, which is quite old. I don't ever know if WAL-G supports it, at least Molecule playbook failed to restart Potgres due to unsupported wal_level value. Upstream PG from PGDG repo works fine.

Example Playbook

Using S3 compatible storage, PGP encryption and geerlingguy.postgresql to setup PostgreSQL itself:

---
- name: Setup PostgreSQL and WAL-G
  hosts: all
  become: yes

  vars:
    walg_user: "{{ postgresql_user }}"
    walg_group: "{{ postgresql_group }}"
    walg_pg_data_dir: "{{ postgresql_data_dir }}"
    walg_pg_config_path: "{{ postgresql_config_path }}"
    walg_pg_service: "{{ postgresql_daemon }}"
    walg_conf:
      PGDATA: "{{ walg_pg_data_dir }}"
      PGHOST: "/var/run/postgresql"
      WALG_S3_PREFIX: "s3://some_bucket"
      AWS_ACCESS_KEY_ID: "VerySecretAccessKey"
      AWS_SECRET_ACCESS_KEY: "VerySecretSecret"
      WALG_COMPRESSION_METHOD: "brotli"
      WALG_DELTA_MAX_STEPS: "6"
      WALG_PGP_KEY_PATH: "{{ walg_postgres_home_dir }}/walg.pgp.public.key"

  roles:
    - role: geerlingguy.postgresql
    - role: wietmann.walg

Testing

This role uses Molecule for testing. Molecule is run against Docker containers with enabled systemd support (see default scenario). Docker Engine, docker library and molecule-docker driver Python packages should be installed on controller host.

geerlingguy.postgresql role is used to install PostgreSQL.

There are two scenarios:

• default - uses PostgreSQL from distro repository
• pgdg - uses PostgreSQL from PGDG repository

Preferred way to test role for compatibility with different versions of Ansible is to use Tox. See tox.ini for the full list of supported Ansible versions.

Run tests for all environments:

tox

List available environments:

tox -l

Run tests only for specific environment (e.g. Ansible 2.9):

tox -e py3-ansible29

Run only specific Molecule subcommand (e.g. molecule verify):

# All test environments
tox -- molecule verify
# Specific test environments
tox -e py3-ansible29 -- molecule verify

License

SPDX:MIT
See the full text in LICENSE file.

Author Information

This role was created in 2021 by Dmitry Danilov.