A Docker image that supports remotely backing up MySQL and PostgreSQL databases to S3-compatible storage buckets (e.g. Amazon S3, Backblaze B2, etc.).

Timing of the backups are determined by a cron job installed inside of the Docker image (located at image/conf/cron.conf) that executes a backup script written in Bash (image/scripts/backup.sh). The backup script dumps the database $DB_NAME using the user $DB_USER (identified by the password $DB_PASS) to /tmp/$DB_NAME.sql. Afterwards, it uploads the database dump to the S3 storage bucket using Duplicity and deletes the local database dump.

The custom Docker image files are stored inside of the image/ directory. There is also a Docker Compose application example you can refer to and use inside of the example/ directory which shows how to utilize this image.

Building The Docker Image

The custom Docker image is stored inside of the image/ directory. You can use the build_image.sh Bash script to build the Docker image with customization support including the image name, tag, path, and more options.

The following arguments are supported when executing the script.

Flag	Default	Description
--name=<NAME>	db-backups	The name of the Docker image.
--tag=<TAG>	latest	The Docker image's tag.
--path=<PATH>	image/	Builds the Docker image inside of <PATH>.
--base-name=<NAME>	debian	The base Docker image (recommend using debian or ubuntu since we rely on the apt package manager).
--base-tag=<TAG>	latest	The base Docker image tag to use.
--no-cache	-	Builds the Docker image with no cache.
--help	-	Prints the help menu.

By default, the cron job that executes the backup script is ran every night at 12:00 (midnight). However, you can easily change this by editing the image/conf/cron.conf file and rebuilding the image. You can use a cron generator tool such as this for assistance!

You may also build the image manually using the following command as root (or using sudo).

docker build -t db-backups:latest image/

Utilizing The Docker Image

I'd recommend giving the (example/) directory a look as it includes Docker Compose configuration files that shows how to use this custom Docker image.

I'd also recommend implementing this image using Docker Compose. For example, in your docker-compose.yml file, you can create the backups service like below.

services:
  db-backups:
    image: db-backups:latest
    hostname: db-backups
    volumes:
      - ./backup-logs:/var/log/backups/
    env_file:
      - ./.env

📝NOTE: The above configuration expects you to store the project's env variables inside a separate file (./env). You can replace the env_file section with environment and pass the env variables inside of the docker-compose.yml file directly in <env_var>: "<value>" format.

Environmental Configuration

All configuration for the backup script is set using environmental variables inside of the Docker container. In the Docker Compose application example inside this repository (example/), we store the environmental variables inside of the example/.env file. By default, the file is called .env.example. Therefore, make sure to rename or copy it to .env.

Here are a list of environmental variables that are supported.

Name	Default	Description
VERBOSE	1	The backup script's verbose level. Log messages go up to verbose level 4 currently.
LOG_DIR	/var/log/backups	The backup script's log directory inside of the Docker container. Leave blank to disable logging to files.
DEL_LOCAL	1	If 1 or higher, deletes the local database dump after uploading it to the S3 bucket.
S3_ENDPOINT	N/A	The S3 endpoint URL.
S3_KEY_ID	N/A	The S3 key ID to use for authentication to the bucket.
S3_APP_KEY	N/A	The S3 app key to use for authentication to the bucket.
S3_BUCKET	N/A	The name of the S3 bucket to store backups in.
S3_BUCKET_DIR	N/A	The directory to store backups in within the bucket.
DB_TYPE	mysql	The type of database backup (currently only supports mysql and postgresql).
DB_HOST	localhost	The database host.
DB_NAME	test-db	The name of the database to backup.
DB_USER	root	The user to authenticate with when performing the backup.
DB_PASS	""	The password to authenticate with when performing the backup.
DB_PORT	3306	The database port to use when connecting to the database.
DUP_FORCE_INC	0	Forces Duplicity to perform an incremental backup.
DUP_FORCE_FULL	0	Forces Duplicity to perform a full backup.
DUP_PASS	12345	This is the GnuPG passphrase which is required for restoring the backup. It is recommended you set and change this value!

Credits

• Christian Deacon