Using PostgreSQL with Docker

PostgreSQL is a powerful, open-source relational database system. Docker is a platform that allows developers to automate the deployment of applications inside lightweight, portable containers. This lesson covers how to set up and use PostgreSQL within Docker containers, enabling easy management of database instances.

• Docker installed on your machine.
• Basic knowledge of PostgreSQL and SQL commands.
• Familiarity with the command line interface (CLI).

3.1 Pulling the PostgreSQL Image

docker pull postgres:latest

This command pulls the latest PostgreSQL image from Docker Hub.

3.2 Running a PostgreSQL Container

docker run --name my_postgres -e POSTGRES_PASSWORD=mysecretpassword -d postgres

This command runs a PostgreSQL container named my_postgres with a specified password for the default user postgres.

4.1 Exposing Ports

docker run --name my_postgres -e POSTGRES_PASSWORD=mysecretpassword -p 5432:5432 -d postgres

This command exposes port 5432 on the host to port 5432 on the PostgreSQL container, allowing you to connect to the database.

4.2 Using a Volume for Data Persistence

docker run --name my_postgres -e POSTGRES_PASSWORD=mysecretpassword -p 5432:5432 -v pgdata:/var/lib/postgresql/data -d postgres

This command mounts a Docker volume pgdata to ensure data persistence across container restarts.

5.1 Connecting to PostgreSQL

You can use psql or any SQL client to connect to your PostgreSQL instance:

docker exec -it my_postgres psql -U postgres

This command opens a PostgreSQL prompt inside the running container.

• Use environment variables for sensitive information.
• Keep your Docker images updated.
• Regularly backup your PostgreSQL data.
• Monitor the performance of your database containers.