Start a Docker container and take a backup

Percona XtraBackup works in combination with a MySQL-compatible database, Percona Server for MySQL, in our scenario. To use Percona XtraBackup, run it in a separate Docker container and then connect the Percona XtraBackup container to the Percona Server for MySQL container. As soon as you start Percona Server for MySQL in a Docker container and create a database and table in Percona Server for MySQL, you are ready to backup your databes with Percona XtraBackup.

The following steps create a Docker volume, start Percona XtraBackup in a Docker continer, take and prepare a backup of Percona Server for MySQL database.

1. Create a Docker volume

   One of the benefits of using a Docker volume for persistent storage with a database is that it allows you to keep your data safe and accessible across different containers. For example, if you want to upgrade your database image to a newer version, you can stop the old container and start a new one with the same volume attached without losing any data. Another benefit is that you can quickly backup and restore your data using the docker cp command or mount the volume to another container.

   $ docker volume create backupvol
   

   Expected output

   backupvol
   

2. Start Percona XtraBackup 8.0.34 in a container, take and prepare a backup

   The docker run command creates and runs a new container from an image. The command modifies the container’s behavior with options.

   In our example, the command has the following options:

   Option	Description
   --name	Provides a name to the container. If you do not use this option, Docker adds a random name.
   --volumes-from	Refers to Percona Server for MySQL and indicates that you intend to use the same data as the psmysql container.
   it	Interacts with the container and be a pseudo-terminal.
   --user root	Sets the user to root inside the Percona XtraBackup container. This option is required to access the MySQL data directory and run the xtrabackup command.
   backup_8034	Indicates the directory inside the container where the backup files are stored.
   -v	Mounts a volume from the host machine to volumes in another container that is being run. In our example, the -v option mounts a volume from the psmysql container to the backupvol volume on the host machine.
   backupvol	Indicates the persistent storage for the database.
   psmysql	Indicates the Percona Server for MySQL container.
   --password	Prompts the user to enter the password for the root user. For convenience you can add the password for the root user to this option, for example, --password=secret. Then the password will be passed automaticaly when running the command. Note that if you specify the password with --password=secret, the password is visible in docker ps, docker ps -a (docker history) and regular ps command.
   8.0.34	Use this tag to specify a specific version. Avoid using the latest tag. In our example, we use the 8.0.34 tag. In Docker, a tag is a label assigned to an image and is used to maintain different versions of an image.

   If you do not add a tag, Docker uses latest as the default tag and downloads the newest image from percona/percona-xtrabackup on the Docker Hub. This image can be in a different series or version from what you expect since the latest image changes over time. The usage of tags ensures that you use compatible versions of Percona Server for MySQL and Percona XtraBackup.

   To connect the Percona XtraBackup container to the Percona Server container, we recommend using the –-user root option in the Docker command.

   • Run a Docker container example

     $ docker run --name pxb --volumes-from psmysql -v backupvol:/backup_8034 -it --user root percona/percona-xtrabackup:8.0.34 /bin/bash -c "xtrabackup --backup --datadir=/var/lib/mysql/ --target-dir=/backup_8034 --user=root --password; xtrabackup --prepare --target-dir=/backup_8034"
     

     You are prompted to enter the password, which is secret, in our example.

     2023-12-21T16:16:10.796716-00:00 0 [Note] [MY-011825] [Xtrabackup] recognized server arguments: --datadir=/var/lib/mysql/2023-12-21T16:16:10.799979-00:00 0 [Note] [MY-011825] [Xtrabackup] recognized client arguments: --backup=1 --target-dir=/backup_8034 --user=root --password
     
     Enter password:
     

   In this example of expected output, we provide the first and last section of the backup log and use ellipses instead of the entire backup log.

   Expected output

   2023-12-14T15:45:16.277503-00:00 0 [Note] [MY-011825] [Xtrabackup] recognized server arguments: --datadir=/var/lib/mysql/ 
   
   2023-12-14T15:45:16.280208-00:00 0 [Note] [MY-011825] [Xtrabackup] recognized client arguments: --backup=1 --target-dir=/backup_80 --user=root --password=* 
   
   xtrabackup version 8.0.34-29 based on MySQL server 8.0.34 Linux (x86_64) (revision id: 5ba706ee) 
   
   2023-12-14T15:45:16.306670-00:00 0 [Note] [MY-011825] [Xtrabackup] perl binary not found. Skipping the version check 
   
   2023-12-14T15:45:16.307026-00:00 0 [Note] [MY-011825] [Xtrabackup] Connecting to MySQL server host: localhost, user: root, password: set, port: not set, socket: not set 
   
   2023-12-14T15:45:16.320214-00:00 0 [Note] [MY-011825] [Xtrabackup] Using server version 8.0.34-26 
   
   ...
   
   2023-12-14T15:45:20.619892-00:00 0 [Note] [MY-011825] [Xtrabackup] completed OK! 
   

   The command runs a Docker container pxb from the percona/percona-xtrabackup:8.0.34 image and mounts two volumes: one from another container named psmysql, which contains Percona Server data directory, and another named backupvol, which is where the backup files are stored. The command also sets the user to root and prompts the user to enter the password. The command then executes two steps:

   • Runs xtrabackup with the --backup option to copy the data files from /var/lib/mysql/ to /backup_8034

   • Runs xtrabackup with the --prepare option to apply the log files and make the backup consistent and ready for restore

   • You can check the Xtrabackup logs with the docker container logs <container-name> command.

     For example:

     $ docker container logs pxb
     

Next steps

Restore the backup

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Last update: 2024-04-04