xtrabackup

This image uses martinhelmich/xtrabackup as a base and tries to provide an entrypoint to support full backup and restore procedures from within rancher

Use case

The image is built with the following use case in mind:

• There is a running mysql flavored server(mysql, mariadb, percona xtradb) which has /var/lib/mysql on a named volume[1]
• Backups are written to a named volume on a convoy vfs - mounted to a hetzner storagebox(cifs)
• Restore is done by starting a new server container, shutting it down, removing the data directory and restoring from the backup.
• A full restore is achieved by switching the sql load balancer to the new container.
• A partial restore is done by attaching a pma to the new container and copying the intended data.
• This is tested on a percona xtradb galera cluster

[1] it is also possible to use the image via --volumes-from on a data container instead of having named volumes but I do not know of a way to leverage this from within rancher as --volumes-from requires a sidekick relationship there.

Usage

The container knows the following commands. Starting the container without a command will prompt the container to print its usage information.

• backup Use xtrabackup to create a backup to /target/YY-mm-dd-HH_ii
  • Set environment variable BACKUP_MODE=FULL to create a backup to /target/full-YY-mm-dd-HH_ii and do not prepare it
  • Set environment variable BACKUP_MODE=INCREMENTAL to create an incremental backup based on the latest full backup found to /target/full-FULL_BACKUP_TIMESTAMP-inc-YY-mm-dd-HH_ii
• restore BACKUP Attempts to restore the given BACKUP from /target/BACKUP
  • If the regex ^full-.*-inc-.* matches the backup name it is treated as incremental backup and the full backup included in its name is restored before the incremental one.
• clear Clears the backup directory in preparation for restoring a backup. This is separate from restore to allow this command to run on all hosts of a galera cluster
• run COMMAND Run the given command within the container
• cleanup Remove the full backup 4 weeks older than the last one
• remove BACKUP Remove the given full backup, its incremental childs and their respective restore services
• help Print Usage

backup

Environment variable	xtrabackup parameter	defaults to
MYSQL_HOST	--host $PARAM	target
MYSQL_PORT	--port $PARAM	3306
MYSQL_USER	--user $PARAM	-
MYSQL_PASSWORD	--password $PARAM	-

Current behavious is to prepare the backup fully aftyer creating it. This will probably change in the future as we start implementing incremental backups and preparing on utility servers.

restore

clear

Clean the mysql database data via rm -Rf /var/lib/mysql/*.
This is intended to be used with run on all hosts and scheduling rule must have service DBSTACK/NEWDBSERVICE to prepare the new database cluster to receive the backup

run COMMAND

Runs the given command as command line within the containers. This is intended to debug the container.

help

Prints usage.
Currently only prints the full overview.

help [COMMAND] might be included in the future if the need arises

Example

• Step 1: Create backup from existing data which is not within

   docker volume create --driver=convoy --name=backup
   docker run -it --volumes-from DB_DATA_VOLUME_CONTAINER -v backup:/target --link DB_SERVER_CONTAINER:target -e MYSQL\_PORT=3306 -e MYSQL\_USER=root -e MYSQL_PASSWORD='PASSWORD' ipunktbs/xtrabackup

• Step 2: Create new PXC cluster from Rancher Catalog

• Step 3: Upgrade PXC service to match your scheduling needs

• Step 4: Stop PXC service

• Step 5: Create ipunktbs/xtrabackup service with

  • Command: clear
  • Scheduling: All hosts, must have service DBSTACK/DBSERVICE
  • Volumes: PXC_NAMED_MYSQL_VOLUME:/var/lib/mysql

• Step 6: Delete the clear service after all instances have successfully finished

• Step 7: Create ipunktbs/xtrabackup service with

  • Command: restore
  • Scheduling: Scale 1, must have service DBSTACK/DBSERVICE
  • Volumes: PXC_NAMED_MYSQL_VOLUME:/var/lib/mysql, backup:/target
  • Note: You might have to do this using rancher-compose until per-volume driver is available in rancher, or create the backup volume with a driver on all hosts

• Step 8: Start the pxc server on the server where the restore container ran and run the command SET GLOBAL wsrep_provider_options="pc.bootstrap=1"; to make it the new master.

• Step 9: Start the other pxc servers and wait for the state sync