PostgresSQL image with Primary & Replica support. In order to build the image, run:

DOCKER_REPO=ghcr.io/mutablelogic/docker-postgres make docker

Replacing the DOCKER_REPO with the repository you want to use.

The image can be run as a primary or replica, depending on the environment variables passed on the docker command line:

• POSTGRES_REPLICATION_PRIMARY: Required for replica The host and port that the replica will use to connect to the primary, in the form host=<hostname> port=5432. When not set, the instance role is a primary.
• POSTGRES_REPLICATION_PASSWORD: Required: The password for the POSTGRES_REPLICATION_USER.
• POSTGRES_REPLICATION_USER: Default is replicator: The user that the primary will use to connect to the replica.
• POSTGRES_REPLICATION_SLOT: Default is replica1 The replication slot for each replica. On the primary, this is a comma-separated list of replication slots. On a replica, this is the name of the replication slot used for syncronization.

Example of running a primary instance, with two replication slots. You should change the password for the POSTGRES_PASSWORD and POSTGRES_REPLICATION_PASSWORD environment variables in this example:

docker volume create postgres-primary docker run \ --rm --name postgres-primary \ -e POSTGRES_REPLICATION_SLOT="replica1,replica2" \ -e POSTGRES_REPLICATION_PASSWORD="postgres" \ -e POSTGRES_PASSWORD="postgres" \ -p 5432:5432 \ -v postgres-primary:/var/lib/postgresql/data \ ghcr.io/mutablelogic/docker-postgres:17-bookworm

You can add additional replication slots later as needed.

When you run a replica instance, the first time it runs it will backup from the primary instance and then start replication. You should change the password for the POSTGRES_PASSWORD and POSTGRES_REPLICATION_PASSWORD environment variables, and set the POSTGRES_REPLICATION_PRIMARY environment variable to the primary instance in this example:

docker volume create postgres-replica1 docker run \ --rm --name postgres-replica1 \ -e POSTGRES_REPLICATION_PRIMARY="host=milou.lan port=5432" \ -e POSTGRES_REPLICATION_SLOT="replica1" \ -e POSTGRES_REPLICATION_PASSWORD="postgres" \ -e POSTGRES_PASSWORD="postgres" \ -p 5433:5432 \ -v postgres-replica1:/var/lib/postgresql/data \ ghcr.io/mutablelogic/docker-postgres:17-bookworm

A second replica (and so forth) can be run in the same way, but with a different port and volume name. You can run up to ten replicas by default.