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+---
+title: 'PostgreSQL ansible role'
+description: 'The ansible role I use to manage my PostgreSQL databases'
+date: '2024-10-09'
+tags:
+- ansible
+- PostgreSQL
+---
+
+## Introduction
+
+Before succumbing to nixos, I had been using an ansible role to manage my PostgreSQL databases. Now that I am in need of it again I refined it a bit: here is the result.
+
+## The role
+
+### Tasks
+
+My `main.yaml` relies on OS specific tasks:
+
+``` yaml
+---
+- name: 'Generate postgres user password'
+ include_tasks: 'generate_password.yaml'
+ vars:
+ name: 'postgres'
+ when: '(ansible_local["postgresql_postgres"]|default({})).password is undefined'
+
+- name: 'Run OS tasks'
+ include_tasks: '{{ ansible_distribution }}.yaml'
+
+- name: 'Start postgresql and activate it on boot'
+ service:
+ name: 'postgresql'
+ enabled: true
+ state: 'started'
+```
+
+Here is an example in `Debian.yaml`:
+
+``` yaml
+---
+- name: 'Install postgresql'
+ package:
+ name:
+ - 'postgresql'
+ - 'python3-psycopg2' # necessary for the ansible postgresql modules
+
+- name: 'Configure postgresql'
+ template:
+ src: 'pg_hba.conf'
+ dest: '/etc/postgresql/15/main/'
+ owner: 'root'
+ group: 'postgres'
+ mode: '0440'
+ notify: 'reload postgresql'
+
+- name: 'Configure postgresql (file that require a restart when modified)'
+ template:
+ src: 'postgresql.conf'
+ dest: '/etc/postgresql/15/main/'
+ owner: 'root'
+ group: 'postgres'
+ mode: '0440'
+ notify: 'restart postgresql'
+
+- meta: 'flush_handlers'
+
+- name: 'Set postgres admin password'
+ shell:
+ cmd: "printf \"ALTER USER postgres WITH PASSWORD '%s';\" \"{{ ansible_local.postgresql_postgres.password }}\" | su -c psql - postgres"
+ when: 'postgresql_password_postgres is defined'
+```
+
+My `generate_password.yaml` will persist a password with a custom fact:
+
+``` yaml
+---
+# Inputs:
+# name: string
+# Outputs:
+# ansible_local["postgresql_" + postgresql.name].password
+- name: 'Generate a password'
+ set_fact: { "postgresql_password_{{ name }}": "{{ lookup('password', '/dev/null length=32 chars=ascii_letters') }}" }
+
+- name: 'Deploy ansible fact to persist the password'
+ template:
+ src: 'postgresql.fact'
+ dest: '/etc/ansible/facts.d/postgresql_{{ name }}.fact'
+ owner: 'root'
+ mode: '0500'
+ vars:
+ password: "{{ lookup('vars', 'postgresql_password_' + name) }}"
+
+- name: 'reload ansible_local'
+ setup: 'filter=ansible_local'
+```
+
+The main entry point of the role is the `database.yaml` task:
+
+``` yaml
+---
+# Inputs:
+# postgresql:
+# name: string
+# extension: list
+# Outputs:
+# ansible_local["postgresql_" + postgresql.name].password
+- name: 'Generate {{ postgresql.name }} password'
+ include_tasks: 'generate_password.yaml'
+ vars:
+ name: '{{ postgresql.name }}'
+ when: '(ansible_local["postgresql_" + postgresql.name]|default({})).password is undefined'
+
+- name: 'Create {{ postgresql.name }} user'
+ community.postgresql.postgresql_user:
+ login_host: 'localhost'
+ login_password: '{{ ansible_local.postgresql_postgres.password }}'
+ name: '{{ postgresql.name }}'
+ password: '{{ ansible_local["postgresql_" + postgresql.name].password }}'
+
+- name: 'Create {{ postgresql.name }} database'
+ community.postgresql.postgresql_db:
+ login_host: 'localhost'
+ login_password: '{{ ansible_local.postgresql_postgres.password }}'
+ name: '{{ postgresql.name }}'
+ owner: '{{ postgresql.name }}'
+
+- name: 'Activate {{ postgres.name }} extensions'
+ community.postgresql.postgresql_ext:
+ db: '{{ postgresql.name }}'
+ login_host: 'localhost'
+ login_password: '{{ ansible_local.postgresql_postgres.password }}'
+ name: '{{ item }}'
+ loop: '{{ postgresql.extensions | default([]) }}'
+```
+
+### Handlers
+
+Here are the two handlers:
+
+``` yaml
+---
+- name: 'reload postgresql'
+ service:
+ name: 'postgresql'
+ state: 'reloaded'
+
+- name: 'restart postgresql'
+ service:
+ name: 'postgresql'
+ state: 'restarted'
+```
+
+### Templates
+
+Here is my usual `pg_hba.conf`:
+
+``` yaml
+###############################################################################
+# \_o< WARNING : This file is being managed by ansible! >o_/ #
+# ~~~~ ~~~~ #
+###############################################################################
+
+local all all peer #unix socket
+
+host all all 127.0.0.0/8 scram-sha-256
+host all all ::1/128 scram-sha-256
+host all all 10.88.0.0/16 scram-sha-256 # podman
+```
+
+Here is my `postgresql.conf` for Debian:
+
+``` yaml
+###############################################################################
+# \_o< WARNING : This file is being managed by ansible! >o_/ #
+# ~~~~ ~~~~ #
+###############################################################################
+
+data_directory = '/var/lib/postgresql/15/main' # use data in another directory
+hba_file = '/etc/postgresql/15/main/pg_hba.conf' # host-based authentication file
+ident_file = '/etc/postgresql/15/main/pg_ident.conf' # ident configuration file
+external_pid_file = '/var/run/postgresql/15-main.pid' # write an extra PID file
+
+port = 5432 # (change requires restart)
+max_connections = 100 # (change requires restart)
+
+unix_socket_directories = '/var/run/postgresql' # comma-separated list of directories
+listen_addresses = 'localhost,10.88.0.1'
+
+shared_buffers = 128MB # min 128kB
+dynamic_shared_memory_type = posix # the default is usually the first option
+max_wal_size = 1GB
+min_wal_size = 80MB
+log_line_prefix = '%m [%p] %q%u@%d ' # special values:
+log_timezone = 'Europe/Paris'
+cluster_name = '15/main' # added to process titles if nonempty
+datestyle = 'iso, mdy'
+timezone = 'Europe/Paris'
+lc_messages = 'en_US.UTF-8' # locale for system error message
+lc_monetary = 'en_US.UTF-8' # locale for monetary formatting
+lc_numeric = 'en_US.UTF-8' # locale for number formatting
+lc_time = 'en_US.UTF-8' # locale for time formatting
+default_text_search_config = 'pg_catalog.english'
+include_dir = 'conf.d' # include files ending in '.conf' from
+```
+
+And here is the simple fact script:
+
+``` shell
+#!/bin/sh
+###############################################################################
+# \_o< WARNING : This file is being managed by ansible! >o_/ #
+# ~~~~ ~~~~ #
+###############################################################################
+set -eu
+
+printf '{"password": "%s"}' "{{ password }}"
+```
+
+## Usage example
+
+I do not call the role from a playbook, I prefer running the setup from an application's role that relies on postgresql using a `meta/main.yaml` containing something like:
+
+``` yaml
+---
+dependencies:
+ - role: 'borg
+ - role: 'postgresql'
+```
+
+Then from a tasks file:
+
+``` yaml
+- include_role:
+ name: 'postgresql'
+ tasks_from: 'database'
+ vars:
+ postgresql:
+ extensions:
+ - 'pgcrypto'
+ name: 'eventline'
+```
+
+Backup jobs can be setup with:
+
+``` yaml
+- include_role:
+ name: 'borg'
+ tasks_from: 'client'
+ vars:
+ client:
+ jobs:
+ - name: 'postgres'
+ command_to_pipe: "su - postgres -c '/usr/bin/pg_dump -b -c -C -d eventline'"
+ name: 'eventline'
+ server: '{{ eventline_adyxax_org.borg }}'
+```
+
+## Conclusion
+
+I enjoy this design, it has served me well.
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 12:18:28 +0000