Documents db backups

Author: MoteHue

doc/source/operations/database-backups.rst

@@ -0,0 +1,40 @@
+================
+Database Backups
+================
+
+An OpenStack deployment includes MariaDB to be used as a database by the
+OpenStack services. Kayobe has `built-in support
+<https://docs.openstack.org/kayobe/latest/administration/overcloud.html#performing-database-backups>`__
+for backing up this database, but these backups are just stored on one of the
+OpenStack controller hosts.
+
+We have a playbook ``tools/upload-database-backup-s3.yml`` which can be used to
+upload these backups to an S3 object store. To use this, you will need:
+
+* The endpoint of the S3 object store.
+
+* EC2 access and secret keys to authenticate to the S3 object store.
+
+* The name of a pre-existing bucket in the S3 object store.
+
+These should be set as follows:
+
+.. code-block:: yaml
+   :caption: ``$KAYOBE_CONFIG_PATH/inventory/group_vars/all/mariadb-backup``
+
+   s3_mariadb_backup_url: "<s3-endpoint>"
+   s3_mariadb_backup_bucket: "<s3-bucket-name>"
+
+.. code-block:: yaml
+   :caption: ``$KAYOBE_CONFIG_PATH/environments/$KAYOBE_ENVIRONMENT/secrets.yml``
+
+   secrets_s3_mariadb_backup_access_key: "<s3-access-key>"
+   secrets_s3_mariadb_backup_secret_key: "<s3-secret-access-key"
+
+You may also want to hook this to run after ``kayobe overcloud database
+backup``:
+
+.. code-block:: bash
+
+   mkdir -p $KAYOBE_CONFIG_PATH/hooks/overcloud-database-backup/post.d/
+   ln -s ../../../ansible/upload-database-backup-s3.yml $KAYOBE_CONFIG_PATH/hooks/overcloud-database-backup/post.d/10-upload-database-backup-s3.yml