mysql-cron-backup

Run mysqldump to backup your databases periodically using the cron task manager in the container. Your backups are saved in /backup. You can mount any directory of your host or a docker volume in /backup. Otherwise, a docker volume is created in the default location.

Table of Contents

• Usage
  • Healthcheck
• Environment Variables
• Uploading Backups to S3 or S3-Compatible Services
• Docker Compose Examples
  • Docker-compose with MYSQL_PASS env var
  • Docker-compose using docker secrets
  • Docker-compose uploading backups to S3-compatible storage
• Restore from a backup

Usage:

docker container run -d \
       --env MYSQL_USER=root \
       --env MYSQL_PASS=my_password \
       --link mysql \
       --volume /path/to/my/backup/folder:/backup \
       fradelg/mysql-cron-backup

Healthcheck

Healthcheck is provided as a basic init control. Container is Healthy after the database init phase, that is after INIT_BACKUP or INIT_RESTORE_LATEST happens without checking if there is an error, Starting otherwise. No other checks are actually provided.

Variables

Database Connection

• MYSQL_HOST: The host/IP of your MySQL database.
• MYSQL_HOST_FILE: The file in the container where to find the host of your MySQL database (cf. Docker secrets). You should use either MYSQL_HOST_FILE or MYSQL_HOST.
• MYSQL_PORT: The port number of your MySQL database.
• MYSQL_USER: The username of your MySQL database.
• MYSQL_USER_FILE: The file in the container where to find the username of your MySQL database (cf. Docker secrets). You should use either MYSQL_USER_FILE or MYSQL_USER.
• MYSQL_PASS: The password of your MySQL database.
• MYSQL_PASS_FILE: The file in the container where to find the password of your MySQL database (cf. Docker secrets). You should use either MYSQL_PASS_FILE or MYSQL_PASS.
• MYSQL_DATABASE: The database name to dump. Default: --all-databases.
• MYSQL_DATABASE_FILE: The file in the container where to find the database name(s) in your MySQL database (cf. Docker secrets). In that file, there can be several database names: one per line. You should use either MYSQL_DATABASE or MYSQL_DATABASE_FILE.

Backup & Scheduling

• CRON_TIME: The interval of cron job to run mysqldump. 0 3 * * sun by default, which is every Sunday at 03:00. It uses UTC timezone.
• MAX_BACKUPS: The number of backups to keep. When reaching the limit, the old backup will be discarded. No limit by default.
• INIT_BACKUP: If set, create a backup when the container starts.
• INIT_RESTORE_LATEST: If set, restores latest backup.
• EXIT_BACKUP: If set, create a backup when the container stops.
• TIMEOUT: Wait a given number of seconds for the database to be ready and make the first backup, 10s by default. After that time, the initial attempt for backup gives up and only the Cron job will try to make a backup.

Options & Compression

• MYSQLDUMP_OPTS: Command line arguments to pass to mysqldump (see mysqldump documentation).
• MYSQL_SSL_OPTS: Command line arguments to use SSL.
• GZIP_LEVEL: Specify the level of gzip compression from 1 (quickest, least compressed) to 9 (slowest, most compressed), default is 6.
• USE_PLAIN_SQL: If set, back up and restore plain SQL files without gzip.
• TZ: Specify timezone in the container. E.g., "Europe/Berlin". Default is UTC.
• REMOVE_DUPLICATES: Use fdupes to remove duplicate database dumps.

Uploading backups to S3 or S3-compatible services (Cloudflare R2, MinIO, Backblaze B2, ...)

When S3_BUCKET is set, every dump is uploaded via the aws CLI right after it's created locally, both under its timestamped name and under latest.<database>.sql[.gz]. Local retention (MAX_BACKUPS, REMOVE_DUPLICATES) is unaffected: it only manages files inside /backup, the S3 upload just mirrors what's written there.

• S3_BUCKET: Name of the bucket to upload backups to. If not set, no upload is performed.
• S3_PATH: Optional key prefix inside the bucket, e.g. my-project/backups. Default: bucket root.
• S3_ENDPOINT: Custom endpoint URL, required for S3-compatible services that aren't AWS, e.g. https://<ACCOUNT_ID>.r2.cloudflarestorage.com for Cloudflare R2.
• S3_REGION: Region passed to the AWS CLI. Default: us-east-1. Some providers (e.g. Cloudflare R2) accept auto.
• AWS_ACCESS_KEY_ID / AWS_ACCESS_KEY_ID_FILE: Access key used to authenticate. Use _FILE for docker secrets.
• AWS_SECRET_ACCESS_KEY / AWS_SECRET_ACCESS_KEY_FILE: Secret key used to authenticate. Use _FILE for docker secrets.
• S3_UPLOAD_OPTS: Extra command line arguments passed to aws s3 cp (e.g. --storage-class STANDARD_IA).

If you want to make this image the perfect companion of your MySQL container, use docker-compose. You can add more services that will be able to connect to the MySQL image using the name my_mariadb, note that you only expose the port 3306 internally to the servers and not to the host.

Security Tip: For production environments, prefer using Docker Secrets (*_FILE variables) or external .env files rather than writing plain-text passwords directly in compose files.

Docker Compose Examples

Docker-compose with MYSQL_PASS env var:

services:
  mariadb:
    image: mariadb
    container_name: my_mariadb
    expose:
      - 3306
    volumes:
      - data:/var/lib/mysql
      # If there is no schema, restore the last created backup (if exists)
      - ${VOLUME_PATH}/backup/latest.${DATABASE_NAME}.sql.gz:/docker-entrypoint-initdb.d/database.sql.gz
    environment:
      - MYSQL_ROOT_PASSWORD=${MARIADB_ROOT_PASSWORD}
      - MYSQL_DATABASE=${DATABASE_NAME}
    restart: unless-stopped

  mysql-cron-backup:
    image: fradelg/mysql-cron-backup
    depends_on:
      - mariadb
    volumes:
      - ${VOLUME_PATH}/backup:/backup
    environment:
      - MYSQL_HOST=my_mariadb
      - MYSQL_USER=root
      - MYSQL_PASS=${MARIADB_ROOT_PASSWORD}
      - MAX_BACKUPS=15
      - INIT_BACKUP=0
      # Every day at 03:00
      - CRON_TIME=0 3 * * *
      # Make it small
      - GZIP_LEVEL=9
      # As of MySQL 8.0.21 this is needed
      - MYSQLDUMP_OPTS=--no-tablespaces
    restart: unless-stopped

volumes:
  data:

Docker-compose using docker secrets:

The database root password passed to docker container by using docker secrets.

In example below, docker is in classic 'docker engine mode' (iow. not swarm mode) and secret sources are local files on host filesystem.

Alternatively, secrets can be stored in docker secrets engine (iow. not in host filesystem).

version: "3.7"

secrets:
  # Place your secret file somewhere on your host filesystem, with your password inside
  mysql_root_password:
    file: ./secrets/mysql_root_password
  mysql_user:
    file: ./secrets/mysql_user
  mysql_password:
    file: ./secrets/mysql_password
  mysql_database:
    file: ./secrets/mysql_database

services:
  mariadb:
    image: mariadb:10
    container_name: my_mariadb
    expose:
      - 3306
    volumes:
      - data:/var/lib/mysql
      - ${VOLUME_PATH}/backup:/backup
    environment:
      - MYSQL_ROOT_PASSWORD_FILE=/run/secrets/mysql_root_password
      - MYSQL_USER_FILE=/run/secrets/mysql_user
      - MYSQL_PASSWORD_FILE=/run/secrets/mysql_password
      - MYSQL_DATABASE_FILE=/run/secrets/mysql_database
    secrets:
      - mysql_root_password
      - mysql_user
      - mysql_password
      - mysql_database
    restart: unless-stopped

  backup:
    build: .
    image: fradelg/mysql-cron-backup
    depends_on:
      - mariadb
    volumes:
      - ${VOLUME_PATH}/backup:/backup
    environment:
      - MYSQL_HOST=my_mariadb
      # Alternatively to MYSQL_USER_FILE, we can use MYSQL_USER=root to use root user instead
      - MYSQL_USER_FILE=/run/secrets/mysql_user
      # Alternatively, we can use /run/secrets/mysql_root_password when using root user
      - MYSQL_PASS_FILE=/run/secrets/mysql_password
      - MYSQL_DATABASE_FILE=/run/secrets/mysql_database
      - MAX_BACKUPS=10
      - INIT_BACKUP=1
      - CRON_TIME=0 0 * * *
    secrets:
      - mysql_user
      - mysql_password
      - mysql_database
    restart: unless-stopped

volumes:
  data:

Docker-compose uploading backups to S3-compatible storage:

Example using Cloudflare R2:

  mysql-cron-backup:
    image: fradelg/mysql-cron-backup
    depends_on:
      - mariadb
    volumes:
      - ${VOLUME_PATH}/backup:/backup
    environment:
      - MYSQL_HOST=my_mariadb
      - MYSQL_USER=root
      - MYSQL_PASS=${MARIADB_ROOT_PASSWORD}
      - S3_BUCKET=my-backups
      - S3_PATH=mysql
      - S3_ENDPOINT=https://${CLOUDFLARE_ACCOUNT_ID}.r2.cloudflarestorage.com
      - S3_REGION=auto
      - AWS_ACCESS_KEY_ID=${R2_ACCESS_KEY_ID}
      - AWS_SECRET_ACCESS_KEY=${R2_SECRET_ACCESS_KEY}
    restart: unless-stopped

Restore from a backup

List all available backups :

See the list of backups in your running docker container, just write in your favorite terminal:

docker container exec <your_mysql_backup_container_name> ls /backup

Restore using a compose file

To restore a database from a certain backup you may have to specify the database name in the variable MYSQL_DATABASE:

mysql-cron-backup:
    image: fradelg/mysql-cron-backup
    command: "/restore.sh /backup/201708060500.${DATABASE_NAME}.sql.gz"
    depends_on:
      - mariadb
    volumes:
      - ${VOLUME_PATH}/backup:/backup
    environment:
      - MYSQL_HOST=my_mariadb
      - MYSQL_USER=root
      - MYSQL_PASS=${MARIADB_ROOT_PASSWORD}
      - MYSQL_DATABASE=${DATABASE_NAME}

Restore using a docker command

docker container exec <your_mysql_backup_container_name> /restore.sh /backup/<your_sql_backup_gz_file>

if no database name is specified, restore.sh will try to find the database name from the backup file.

Automatic backup and restore on container starts and stops

Set INIT_RESTORE_LATEST to automatic restore the last backup on startup. Set EXIT_BACKUP to automatic create a last backup on shutdown.

  mysql-cron-backup:
    image: fradelg/mysql-cron-backup
    depends_on:
      - mariadb
    volumes:
      - ${VOLUME_PATH}/backup:/backup
    environment:
      - MYSQL_HOST=my_mariadb
      - MYSQL_USER=${MYSQL_USER}
      - MYSQL_PASS=${MYSQL_PASSWORD}
      - MAX_BACKUPS=15
      - INIT_RESTORE_LATEST=1
      - EXIT_BACKUP=1
      # Every day at 03:00
      - CRON_TIME=0 3 * * *
      # Make it small
      - GZIP_LEVEL=9
    restart: unless-stopped

volumes:
  data:

Docker database image could expose a directory you could add files as init sql script.

  mysql:
    image: mysql
    expose:
      - 3306
    volumes:
      - data:/var/lib/mysql
      # If there is not scheme, restore using the init script (if exists)
      - ./init-script.sql:/docker-entrypoint-initdb.d/database.sql.gz
    environment:
      - MYSQL_ROOT_PASSWORD=${MYSQL_ROOT_PASSWORD}
      - MYSQL_DATABASE=${DATABASE_NAME}
    restart: unless-stopped

  mariadb:
    image: mariadb
    expose:
      - 3306
    volumes:
      - data:/var/lib/mysql
      # If there is not scheme, restore using the init script (if exists)
      - ./init-script.sql:/docker-entrypoint-initdb.d/database.sql.gz
    environment:
      - MYSQL_ROOT_PASSWORD=${MARIADB_ROOT_PASSWORD}
      - MYSQL_DATABASE=${DATABASE_NAME}
    restart: unless-stopped