koehn/postgres-wal-g repository overview

⁠Postgres WAL-G

This image extends the stock Postgres Image⁠ and adds WAL-G⁠ support, along with some helpful scripts. It allows you to simply and easily create continuous, encrypted archives of Postgres databases in S3-compatible storage.

⁠Source

The source code is available here⁠.

⁠Environment

To use the image, you'll need to configure a bucket on your favorite S3- compatible provider, and set a few environment variables:

• AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY that can read/write files to your bucket
• AWS_ENDPOINT (et al) to tell WAL-G where to archive (see WAL-G documentation⁠ for details)
• WALG_S3_PREFIX to tell WAL-G which bucket and prefix you'd like to use
• WALG_LIBSODIUM_KEY to encrypt the files stored in S3

⁠Configuration

In your /var/lib/postgresql/data/pgsql/postgresql.conf file, set your archive settings⁠. Importantly, you should set archive_mode = on and archive_command = 'wal-g wal-push %p'. This will tell Postgres to have WAL-G send WAL files to S3.

⁠Full Backups

To run a full backup, simply run /wal-g/backup.sh.

⁠Continuous Backups

These will happen automatically once you've started Postgres with your edited postgresql.conf file (see Configuration⁠, above).

⁠Recovery

Testing recovery is simple: run a new Docker container with the correct environment variables set and run /wal-g/recover.sh. It will:

1. Recover from the most recent full backup
2. Configure Postgres to not accept incoming connections or perform streaming backups until the recovery is complete (important for testing!)
3. Configure Postgres to apply all the WAL files
4. Shut down Postgres, re-enable incoming connections and streaming backups

At this point you should have high confidence that the recovery was successful. If you start your recovered backup, be sure to turn archive_mode = off to avoid pushing additional WAL files to S3!

⁠Postgres Versions

Currently I build for Postgres 17, but you can build for whatever version that wal-g supports.