Configure PostgreSQL and pgAdmin with Docker Compose

2020, July 13

#postgres #pgadmin #docker #docker-compose

Docker is a set of tools that utilises OS-level virtualization to running software in packages called container.

While Docker is mainly used in deployment, it can also be use in development environment. By running a container for development environment, we can avoid to install a bunch of tools or languages on our machine.

For example, we can use Docker to run service such as postgres and pgadmin for database service and administration platform for PostgreSQL respectively in a container.

To demonstrate, we will configure Postgres and pgAdmin with Docker Compose for database service for our development environment.

Tools
Create a Docker Compose file
- postgres
- pgadmin
- Example
Running Docker Compose
Open pgAdmin
- Setup database
Stopping Docker Compose
References

Tools

First, we need to install the tools required.

Both can be installed by referring to the official guide on how to install based on our machine platform.

Create a Docker Compose file

Docker Compose is a tool for defining and running multi-container Docker applications. By using Docker Compose, we can orchestrate on how the applications/services start in the container by a single command.

Moreover, Docker Compose allows us to:

Start, stop, and rebuild services
View the status of running services
Stream the log output of running services
Run a one-off command on a service

Next, we are going to create a Docker Compose file docker-compose.yml to define the services that we are going to run in the container.

The services are:

postgres: PostgreSQL database service
pgadmin: Administration and development platform for PostgreSQL

postgres

Below is the snippet for the service:

postgres:
  image: postgres:12.3-alpine
  restart: always
  environment:
    POSTGRES_PASSWORD: postgres
    POSTGRES_USER: postgres
  volumes:
    - postgres:/var/lib/postgresql/data

Explanation

image: Specify the image to start the container from. In this case, we are going to use postgres:12.3-alpine from Docker Hub.
restart: Configure container to always restart if container stopped unexpectedly.
environment: Configure environment variable for database superuser authentication.
volumes: Mount named volumes for database files.

pgadmin

Below is the snippet for the service:

pgadmin:
  image: dpage/pgadmin4:4.23
  environment:
    PGADMIN_DEFAULT_EMAIL: admin@pgadmin.com
    PGADMIN_DEFAULT_PASSWORD: password
    PGADMIN_LISTEN_PORT: 80
  ports:
    - 15432:80
  volumes:
    - pgadmin:/var/lib/pgadmin
  depends_on:
    - postgres

Explanation

image: Specify the image to start the container from. In this case, we are going to use dpage/pgadmin4:4.23 from Docker Hub.
environment: Configure environment variable for application authentication and setup.
ports: Map port between host machine 15432 and container 80.
volumes: Mount named volumes for application files.
depends_on: Define the dependencies of services. This allow us to deploy service in order; e.g. postgres -> pgadmin.

Example

Then, we will going to put all services' configuration in file docker-compose.yml. Because we are using the named volume, we also need to configure the volumes based on the name we used in services.

Snippet

version: "3"

services:
  postgres:
    image: postgres:12.3-alpine
    restart: always
    environment:
      POSTGRES_PASSWORD: postgres
      POSTGRES_USER: postgres
    volumes:
      - postgres:/var/lib/postgresql/data

  pgadmin:
    image: dpage/pgadmin4:4.23
    environment:
      PGADMIN_DEFAULT_EMAIL: admin@pgadmin.com
      PGADMIN_DEFAULT_PASSWORD: password
      PGADMIN_LISTEN_PORT: 80
    ports:
      - 15432:80
    volumes:
      - pgadmin:/var/lib/pgadmin
    depends_on:
      - postgres

volumes:
  postgres:
  pgadmin:

Running Docker Compose

First, we are going to check and validate the Compose file by execute command: docker-compose config.

Figure 01: Example docker-compose config output

Next, we are deploying and running the service by execute command: docker-compose up -d.

Figure 02: Example docker-compose up -d output

The output may vary depends on if we already downloaded the images and setup the volumes.

To check if services are running successfully, we can use command: docker-compose ps.

Figure 03: Example docker-compose ps output

Open pgAdmin

After running Docker Compose services, open web browser and go to localhost:15432. The port number is based on the mapping we configured under pgadmin service.

Then key-in the email and password configured using the environment variable: PGADMIN_DEFAULT_EMAIL and PGADMIN_DEFAULT_PASSWORD.

Figure 04: pgAdmin login page

Setup database

Click Add New Server under Quick Links.

Figure 05: Add new server

Enter Name under General. The value can be anything.

Figure 06: Server name

Enter Host name/address, Username and Password under Connection.

For Host name/address, the value is the Docker Compose database service name, in our case is postgres.
For Username, the value is the environment variable POSTGRES_USER.
For Password, the value is the environment variable POSTGRES_PASSWORD.

Figure 07: Server connection