borg_client: refactor database related vars/tasks

Move backup-related variable defaults from the database roles into the
borg_client role. Also check group membership to guard installation of
database backup helper scripts.

docs/backups.md

@@ -76,12 +76,13 @@ or just a sub-directory:
 
 ### Mariadb
 
-For Mariadb backups are made using mariabackup to `mysql_backup_dir`.Backups can are made and
-restored using the `mariabackup` tool. See also [official MariaDB docs](https://mariadb.com/kb/en/full-backup-and-restore-with-mariabackup/).
+For Mariadb backups are made using mariabackup to `backup_mysql_dir`. Backups
+are made and can be restored using the `mariadb-backup` tool. See also
+[official MariaDB docs](https://mariadb.com/kb/en/full-backup-and-restore-with-mariabackup/).
 
 ### PostgreSQL
 
-For PostgreSQL backups are made using pg_dump to `postgres_backup_dir`.
+For PostgreSQL backups are made using pg_dump to `backup_postgres_dir`.
 
 Restoring backups can be done with `pg_restore`. See also [official PostgreSQL docs](https://www.postgresql.org/docs/current/app-pgrestore.html).
 

roles/borg_client/defaults/main.yml

@@ -7,3 +7,7 @@ backup_hosts:
     dir: "~/backup/{{ inventory_hostname }}"
     suffix: "-offsite"
     borg_cmd: "/usr/bin/borg --remote-path=borg1"
+
+backup_postgres_dir: /root/backup-postgres
+backup_mysql_dir: /root/backup-mysql
+backup_mysql_defaults: /root/.backup-my.cnf

roles/borg_client/tasks/main.yml

@@ -27,31 +27,26 @@
   template: src=borg-backup.sh.j2 dest=/usr/local/bin/borg-backup{{ item['suffix'] }}.sh owner=root group=root mode=0755
   loop: "{{ backup_hosts }}"
 
-- name: Install postgres backup script
-  template: src=backup-postgres.sh.j2 dest=/usr/local/bin/backup-postgres.sh owner=root group=root mode=0755
-  when: postgres_backup_dir is defined
-
-- name: Check whether postgres user exists
-  command: getent passwd postgres
-  register: check_postgres_user
-  ignore_errors: true
-  changed_when: check_postgres_user.stdout | length > 0
-
-- name: Make postgres backup directory
-  file: path={{ postgres_backup_dir }} owner=root group=root mode=0755 state=directory
-  when: check_postgres_user is succeeded and postgres_backup_dir is defined
-
-- name: Install mysql backup script
-  template: src=backup-mysql.sh.j2 dest=/usr/local/bin/backup-mysql.sh owner=root group=root mode=0755
-  when: mysql_backup_dir is defined
-
-- name: Install mysql backup config
-  template: src=backup-my.cnf.j2 dest={{ mysql_backup_defaults }} owner=root group=root mode=0644
-  when: mysql_backup_defaults is defined
-
-- name: Create mysql backup directory
-  file: path={{ mysql_backup_dir }} state=directory owner=root group=root mode=0755
-  when: mysql_backup_dir is defined
+- name: Set up backup helpers for PostgreSQL databases
+  when: "'postgresql_servers' in group_names"
+  block:
+    - name: Install postgres backup script
+      template: src=backup-postgres.sh.j2 dest=/usr/local/bin/backup-postgres.sh owner=root group=root mode=0755
+
+    - name: Make postgres backup directory
+      file: path={{ backup_postgres_dir }} owner=root group=root mode=0755 state=directory
+
+- name: Set up backup helpers for MariaDB databases
+  when: "'mysql_servers' in group_names"
+  block:
+    - name: Install mysql backup script
+      template: src=backup-mysql.sh.j2 dest=/usr/local/bin/backup-mysql.sh owner=root group=root mode=0755
+
+    - name: Install mysql backup config
+      template: src=backup-my.cnf.j2 dest={{ backup_mysql_defaults }} owner=root group=root mode=0644
+
+    - name: Create mysql backup directory
+      file: path={{ backup_mysql_dir }} state=directory owner=root group=root mode=0755
 
 - name: Install systemd services for backup
   template: src={{ item }}.j2 dest=/etc/systemd/system/{{ item }} owner=root group=root mode=0644

roles/borg_client/templates/backup-mysql.sh.j2

@@ -2,8 +2,8 @@
 
 set -e
 
-mysql_opts="--defaults-file={{mysql_backup_defaults}}"
-backupdir="{{mysql_backup_dir}}"
+mysql_opts="--defaults-file={{ backup_mysql_defaults }}"
+backupdir="{{ backup_mysql_dir }}"
 
 [[ ! -d "$backupdir" ]] && mkdir -p "$backupdir"
 rm -rf "${backupdir:?}"/*

roles/borg_client/templates/backup-postgres.sh.j2

@@ -11,9 +11,9 @@ for db in "${DBLIST[@]}"; do
         if [[ $db =~ template[01] ]]; then
                 continue;
         fi
-        echo "Dumping $db to {{ postgres_backup_dir }}";
-        sudo -u postgres pg_dump --serializable-deferrable -Fc "$db" > "{{ postgres_backup_dir }}/$db.dump"
+        echo "Dumping $db to {{ backup_postgres_dir }}";
+        sudo -u postgres pg_dump --serializable-deferrable -Fc "$db" > "{{ backup_postgres_dir }}/$db.dump"
 done
 
-echo "Dumping globals to {{ postgres_backup_dir }}"
-sudo -u postgres pg_dumpall --globals-only > "{{ postgres_backup_dir }}/globals.sql.dump"
+echo "Dumping globals to {{ backup_postgres_dir }}"
+sudo -u postgres pg_dumpall --globals-only > "{{ backup_postgres_dir }}/globals.sql.dump"

roles/mariadb/defaults/main.yml

@@ -23,6 +23,3 @@ mariadb_innodb_flush_log_at_trx_commit: '1'
 mariadb_innodb_stats_sample_pages: '32'
 mariadb_innodb_thread_concurrency: '8'
 mariadb_innodb_file_per_table: true
-
-mysql_backup_dir: '/root/backup-mysql'
-mysql_backup_defaults: '/root/.backup-my.cnf'

roles/postgres/defaults/main.yml

@@ -18,5 +18,3 @@ postgres_hosts4: []
 postgres_hosts6: []
 postgres_ssl_hosts4: []
 postgres_ssl_hosts6: []
-
-postgres_backup_dir: '/root/backup-postgres'