Following the series of blogs started by Peter Zaitsev in Installing MySQL with Docker, on deploying Docker containers running open source databases, in this article, I’ll demonstrate how to install PostgreSQL using Docker.
Before proceeding, it is important to remind you of Peter’s warning from his article, which applies here as well:
“The following instructions are designed to get a test instance running quickly and easily; you do not want to use these for production deployments.”
We intend to show how to bring up PostgreSQL instance(s) into Docker containers. Moreover, you will find some basic Docker management operations and some snippets containing examples, always based on the Docker Hub PostgreSQL official image.
Installing
Starting with the installation, the following example shows how to bring up a Docker container within the latest PostgreSQL release from Docker Hub. It is required to provide the password of the Postgres user at the moment you are launching the container; otherwise, the container will not be created:
$ docker run --name dockerPostgreSQL \ -e POSTGRES_PASSWORD=secret \ -d postgres:latest
Once you start the container, you can check if it successfully started with docker inspect:
$ docker inspect -f '{{.State.Running}}' dockerPostgreSQL
trueIf not, you can try starting it manually (you will see how to do it on the Managing the PostgreSQL Containers section).
Getting Connected to the Containerized Instance
The snippet below will show you how to connect to your PostgreSQL containerized instance.
- Directly from docker:
$ docker exec -it dockerPostgreSQL psql --user postgres postgres=# \conninfo You are connected to database "postgres" as user "postgres" via socket in "/var/run/postgresql" at port "5432".
- Or from a PostgreSQL client connecting to its IP address, which you can obtain with the command docker inspect:
$ docker inspect -f '{{.NetworkSettings.IPAddress}}' dockerPostgreSQL
172.16.0.12
$ psql --user postgres --port 5432 --host 172.16.0.12
postgres=# \conninfo
You are connected to database "postgres" as user "postgres" on host "172.16.0.12" at port "50432".
Managing the PostgreSQL Containers
The command below will show you how to list all active containers and their respective statuses:
$ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 7f88656c4864 postgres:11 "docker-entrypoint..." 4 minutes ago Up 4 minutes 0.0.0.0:50432->5432/tcp dockerPostgreSQL11 8aba8609dabc postgres:11.5 "docker-entrypoint..." 21 minutes ago Up 21 minutes 5432/tcp dockerPostgreSQL115 15b9e0b789dd postgres:latest "docker-entrypoint..." 32 minutes ago Up 32 minutes 5432/tcp dockerPostgreSQL
To stop one of the containers, do:
$ docker stop dockerPostgreSQL
To start a container:
$ docker start dockerPostgreSQL
Finally, to remove a container, first stop it and then:
$ docker rm dockerPostgreSQL
Customizing PostgreSQL settings in the container
Let’s say you want to define different parameters for the PostgreSQL server running on Docker. You can create a custom postgresql.conf configuration file to replace the default one used with Docker:
$ docker run --name dockerPostgreSQL11 -p 50433:5432 -v "$PWD/my-postgres.conf":/etc/postgresql/postgresql.conf -e POSTGRES_PASSWORD=scret -d postgres:11
Another example of how to pass startup arguments is changing the directory which stores the wal files:
$ docker run --name dockerPostgreSQL11 -p 50433:5432 -v "$PWD/my-postgres.conf":/etc/postgresql/postgresql.conf -e POSTGRES_PASSWORD=scret -e POSTGRES_INITDB_WALDIR=/backup/wal -d postgres:11
Running Different PostgreSQL Versions in Different Containers
You can launch multiple PostgreSQL containers, each running a different PostgreSQL version. In the example below, you will find how to start up a 10.5 PostgreSQL version:
$ docker run --name dockerPostgreSQL105 -p 50433:5432 -e POSTGRES_PASSWORD=scret -d postgres:10.5 7f51187d32f339688c2f450ecfda6b7552e21a93c52f365e75d36238f5905017
Here is how you could launch a PostgreSQL 11 container:
$ docker run --name dockerPostgreSQL11 -p 50432:5432 -e POSTGRES_PASSWORD=scret -d postgres:11 7f88656c4864864953a5491705ac7ca882882df618623b1e5664eabefb662733
After that, by reissuing the status command, you will see all of the already created ones:
$ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES e06e637ae090 postgres:10.5 "docker-entrypoint..." 4 seconds ago Up 4 seconds 0.0.0.0:50433->5432/tcp dockerPostgreSQL105 7f88656c4864 postgres:11 "docker-entrypoint..." About an hour ago Up About an hour 0.0.0.0:50432->5432/tcp dockerPostgreSQL11 15b9e0b789dd postgres:latest "docker-entrypoint..." 2 hours ago Up 2 hours 5432/tcp dockerPostgreSQL
You will notice that both 10.5 and 11 were created with different port mappings. Locally into the container, both are listening on 5432 but are externally mapped to different ports. Therefore, you will be able to access all of them externally.
You will find even more details on the PostgreSQL Hub Docker site.
Percona Distribution for PostgreSQL provides the best and most critical enterprise components from the open-source community in a single distribution, designed and tested to work together.