docker-pg_backup

Docker container with pg_backup_rotated.sh script from https://wiki.postgresql.org/wiki/Automated_Backup_on_Linux This image runs pg_backup_rotated.sh daily via cron at configurable time. pg_backup_rotated.sh produces backups of various configurable formats and rotates weekly and daily backups.

Docker build variables:

• POSTGRES_IMAGE_VERSION - Postgres docker image tag this image will be based on. ('alpine' by default)

Docker environment variables:

• POSTGRES_HOSTNAME - ip/hostname of postgres server
• POSTGRES_USER - user to connect as ('postgres' by default)
• POSTGRES_PASSWORD - password of POSTGRES_USER
• POSTGRES_PASSWORD_FILE - location of file containing password of POSTGRES_USER (can be /run/secrets/SECRETNAME if you put password in SECRETNAME)
• CRON_RUN_MINUTE, CRON_RUN_HOUR - run backups daily at this time every day
• WEEKS_TO_KEEP - how many weeks to keep weekly backups (default 5)
• DAYS_TO_KEEP - number of days to keep daily backups (default 7)
• DAY_OF_WEEK_TO_KEEP - which day to take the weekly backup from (1-7 = Monday-Sunday, default 5-Friday)
• ENABLE_GLOBALS_BACKUPS - will produce gzipped sql file containing the cluster globals, like users and passwords, if set to "yes" (default)
• ENABLE_PLAIN_BACKUPS - will produce a gzipped plain-format backup if set to "yes" (default)
• ENABLE_CUSTOM_BACKUPS - will produce a custom-format backup if set to "yes" (default)
• SCHEMA_ONLY_LIST - List of strings to match against in database name, separated by space or comma, for which we only wish to keep a backup of the schema, not the data. Any database names which contain any of these values will be considered candidates. (e.g. "system_log" will match "dev_system_log_2010-01"). Default is empty list.

Volumes:

• /backups - backups go there

Optional volumes:

• /etc/localtime - map your host /etc/localtime there read-only to have cron operate in host's timezone

You can also tmpfs /var/lib/postgresql/data, it is exported by base image but is not used in this image

Test: A docker-compose-example.yml is provided to help with testing. Check it for further details.

You can quickly try something like:

$ docker-compose -f docker-compose-example.yml up -d pg_backup_test
$ docker exec -it docker-pg_backup-pg_backup_test-1 bash
bash-5.1# crontab -l
10 3 * * * /pgpass.sh /pg_backup_rotated.sh
bash-5.1# /pgpass.sh /pg_backup_rotated.sh
Making backup directory in /backups/2022-03-24-daily/


Performing globals backup
--------------------------------------------

....

bash-5.1# gzip -cd /backups/2022-03-24-daily/postgres.sql.gz
...

The backup script code is taken as-is from postgress wiki, I am not sure which license is it, I claim no rights to this code. Configuration script is based on config file from postgres wiki. The code that is written by me is in the public domain (CC0).