mysql-backup

Overview

mysql-backup is a simple way to do MySQL database backups and restores when the database is running in a container.

It has the following features:

dump and restore
dump to local filesystem or to SMB server
select database user and password
connect to any container running on the same system
select how often to run a dump
select when to start the first dump, whether time of day or relative to container start time

Please see CONTRIBUTORS.md for a list of contributors.

Backup

To run a backup, launch mysql-backup image as a container with the correct parameters. Everything is controlled by environment variables passed to the container.

For example:

docker run -d --restart=always -e DB_DUMP_FREQ=60 -e DB_DUMP_BEGIN=2330 -e DB_DUMP_TARGET=/db -e DB_SERVER=my-db-container -v /local/file/path:/db deitch/mysql-backup

The above will run a dump every 60 minutes, beginning at the next 2330 local time, from the database accessible in the container my-db-container.

The following are the environment variables for a backup:

You should consider the use of --env-file=, docker secrets to keep your secrets out of your shell history

DB_SERVER: hostname to connect to database. Required.
DB_PORT: port to use to connect to database. Optional, defaults to 3306
DB_USER: username for the database
DB_PASS: password for the database
DB_NAMES: names of databases to dump; defaults to all databases in the database server
DB_DUMP_FREQ: How often to do a dump, in minutes. Defaults to 1440 minutes, or once per day.
DB_DUMP_BEGIN: What time to do the first dump. Defaults to immediate. Must be in one of two formats:
- Absolute: HHMM, e.g. 2330 or 0415
- Relative: +MM, i.e. how many minutes after starting the container, e.g. +0 (immediate), +10 (in 10 minutes), or +90 in an hour and a half
RUN_ONCE: Run the backup once and exit if RUN_ONCE is set. Useful if you use an external scheduler (e.g. as part of an orchestration solution like Cattle or Docker Swarm or kubernetes cron jobs) and don't want the container to do the scheduling internally. If you use this option, the DB_DUMP_FREQ and DB_DUMP_BEGIN become obsolete.
DB_DUMP_DEBUG: If set to true, print copious shell script messages to the container log. Otherwise only basic messages are printed.
DB_DUMP_TARGET: Where to put the dump file, should be a directory. Supports three formats:
- Local: If the value of DB_DUMP_TARGET starts with a / character, will dump to a local path, which should be volume-mounted.
- SMB: If the value of DB_DUMP_TARGET is a URL of the format smb://hostname/share/path/ then it will connect via SMB.
- S3: If the value of DB_DUMP_TARGET is a URL of the format s3://bucketname/path then it will connect via awscli.
AWS_ACCESS_KEY_ID: AWS Key ID
AWS_SECRET_ACCESS_KEY: AWS Secret Access Key
AWS_DEFAULT_REGION: Region in which the bucket resides
SMB_USER: SMB username. May also be specified in DB_DUMP_TARGET with an smb:// url. If both specified, this variable overrides the value in the URL.
SMB_PASS: SMB password. May also be specified in DB_DUMP_TARGET with an smb:// url. If both specified, this variable overrides the value in the URL.

In addition, any environment variable that starts with MYSQLDUMP_ will have the MYSQLDUMP_ part stripped off, and the rest passed as an option to mysqldump. For example, MYSQLDUMP_max_allowed_packet=123455678 will run mysqldump --max_allowed_packet=123455678.

Database Container

In order to perform the actual dump, mysql-backup needs to connect to the database container. You must pass the database hostname - which can be another container or any database process accessible from the backup container - by passing the environment variable DB_SERVER with the hostname or IP address of the database. You may override the default port of 3306 by passing the environment variable DB_PORT.

docker run -d --restart=always -e DB_USER=user123 -e DB_PASS=pass123 -e DB_DUMP_FREQ=60 -e DB_DUMP_BEGIN=2330 -e DB_DUMP_TARGET=/db -e DB_SERVER=my-db-container -v /local/file/path:/db deitch/mysql-backup

Dump Target

The dump target is where you want the backup files to be saved. The backup file always is a gzipped file the following format:

db_backup_YYYYMMDDHHmm.sql.gz

Where:

YYYY = year in 4 digits
MM = month number from 01-12
DD = date for 01-31
HH = hour from 00-23
mm = minute from 00-59

The time used is UTC time at the moment the dump begins.

The dump target is the location where the dump should be placed, defaults to /backup in the container. Of course, having the backup in the container does not help very much, so we very strongly recommend you volume mount it outside somewhere. See the above example.

If you use a URL like smb://host/share/path, you can have it save to an SMB server. If you need loging credentials, use smb://user:pass@host/share/path.

Note that for smb, if the username includes a domain, e.g. your user is mydom\myuser, then you should use the samb convention of replacing the '' with a ';'. In other words smb://mydom;myuser:pass@host/share/path

If you use a URL like s3://bucket/path, you can have it save to an S3 bucket.

Note that for s3, you'll need to specify your AWS credentials and default AWS region via AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY and AWS_DEFAULT_REGION

Backup pre and post processing

Any executable script with .sh extension in /scripts.d/pre-backup/ or /scripts.d/post-backup/ directories in the container will be executed before and after the backup dump process has finished respectively, but before uploading the backup file to its ultimate target. This is useful if you need to include some files along with the database dump, for example, to backup a WordPress install.

To use them you need to add a host volume that points to the post-backup scripts in the docker host. Start the container like this:

docker run -d --restart=always -e DB_USER=user123 -e DB_PASS=pass123 -e DB_DUMP_FREQ=60 \
  -e DB_DUMP_BEGIN=2330 -e DB_DUMP_TARGET=/db -e DB_SERVER=my-db-container:db \
  -v /path/to/pre-backup/scripts:/scripts.d/pre-backup \
  -v /path/to/post-backup/scripts:/scripts.d/post-backup \
  -v /local/file/path:/db \
  deitch/mysql-backup

Or, if you prefer compose:

version: '2.1'
services:
  backup:
    image: deitch/mysql-backup
    restart: always
    volumes:
     - /local/file/path:/db
     - /path/to/pre-backup/scripts:/scripts.d/pre-backup
     - /path/to/post-backup/scripts:/scripts.d/post-backup
    env:
     - DB_DUMP_TARGET=/db
     - DB_USER=user123
     - DB_PASS=pass123
     - DB_DUMP_FREQ=60
     - DB_DUMP_BEGIN=2330
     - DB_SERVER=mysql_db
  mysql_db:
    image: mysql
    ....

The scripts are executed in the entrypoint script, which means it has access to all exported environment variables. The following are available, but we are happy to export more as required (just open an issue or better yet, a pull request):

DUMPFILE: full path in the container to the output file
NOW: date of the backup, as included in DUMPFILE and given by date -u +"%Y%m%d%H%M%S"
DUMPDIR: path to the destination directory so for example you can copy a new tarball including some other files along with the sql dump.
DB_DUMP_DEBUG: To enable debug mode in post-backup scripts.

In addition, all of the environment variables set for the container will be available to the script.

For example, the following script will rename the backup file after the dump is done:

#!/bin/bash
# Rename backup file.
if [[ -n "$DB_DUMP_DEBUG" ]]; then
  set -x
fi

if [ -e ${DUMPFILE} ];
then
  now=$(date +"%Y-%m-%d-%H_%M")
  new_name=db_backup-${now}.gz
  old_name=$(basename ${DUMPFILE})
  echo "Renaming backup file from ${old_name} to ${new_name}"
  mv ${DUMPFILE} ${DUMPDIR}/${new_name}
else
  echo "ERROR: Backup file ${DUMPFILE} does not exist!"
fi

You can think of this as a sort of basic plugin system. Look at the source of the entrypoint script for other variables that can be used.

Restore

Dump Restore

If you wish to run a restore to an existing database, you can use mysql-backup to do a restore.

You need only the following environment variables:

You should consider the use of --env-file= to keep your secrets out of your shell history

DB_USER: username for the database
DB_PASS: password for the database
DB_RESTORE_TARGET: path to the actual restore file, which should be a gzip of an sql dump file. The target can be an absolute path, which should be volume mounted, an smb or S3 URL, similar to the target.
DB_DUMP_DEBUG: if true, dump copious outputs to the container logs while restoring.
To use the S3 driver AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY and AWS_DEFAULT_REGION will need to be defined.

Examples:

Restore from a local file: docker run -e DB_USER=user123 -e DB_PASS=pass123 -e DB_RESTORE_TARGET=/backup/db_backup_201509271627.sql.gz -v /local/path:/backup deitch/mysql-backup
Restore from an SMB file: docker run -e DB_USER=user123 -e DB_PASS=pass123 -e DB_RESTORE_TARGET=smb://smbserver/share1/backup/db_backup_201509271627.sql.gz deitch/mysql-backup
Restore from an S3 file: docker run -e AWS_ACCESS_KEY_ID=awskeyid -e AWS_SECRET_ACCESS_KEY=secret -e AWS_DEFAULT_REGION=eu-central-1 -e DB_USER=user123 -e DB_PASS=pass123 -e DB_RESTORE_TARGET=s3://bucket/path/db_backup_201509271627.sql.gz deitch/mysql-backup

Using docker (or rancher) secrets

Environment variables used in this image can be passed in files as well. This is useful when you are using docker (or rancher) secrets for storing sensitive information.

As you can set environment variable with -e ENVIRONMENT_VARIABLE=value, you can also use -e ENVIRONMENT_VARIABLE_FILE=/path/to/file. Contents of that file will be assigned to the environment variable.

Example:

docker run -d \
  -e DB_HOST_FILE=/run/secrets/DB_HOST \
  -e DB_USER_FILE=/run/secrets/DB_USER \
  -e DB_PASS_FILE=/run/secrets/DB_PASS \
  -v /local/file/path:/db \
  deitch/mysql-backup

Restore pre and post processing

As with backups pre and post processing, you can do the same with restore operations. Any executable script with .sh extension in /scripts.d/pre-restore/ or /scripts.d/post-restore/ directories in the container will be executed before the restore process starts and after it finishes respectively. This is useful if you need to restore a backup file that includes some files along with the database dump.

For example, to restore a WordPress install, you would uncompress a tarball containing the db backup and a second tarball with the contents of a WordPress install on pre-restore. Then on post-restore, uncompress the WordPress files on the container's web server root directory.

For an example take a look at the post-backup examples, all variables defined for post-backup scripts are available for pre-processing too. Also don't forget to add the same host volumes for pre-restore and post-restore directories as described for post-backup processing.

Automated Build

This github repo is the source for the mysql-backup image. The actual image is stored on the docker hub at deitch/mysql-backup, and is triggered with each commit to the source by automated build via Webhooks.

There are 2 builds: 1 for version based on the git tag, and another for the particular version number.

License

Released under the MIT License. Copyright Avi Deitcher https://github.com/deitch

Thanks to the kind contributions and support of TraderTools.

th0th/mysql-backup