developer-roadmap/src/data/roadmaps/docker/content/105-using-third-party-images/100-databases.md

Using Third Party Images: Databases

Databases are an essential component of many applications and services. In this section, we'll discuss how to use third party images for databases within your Docker projects.

Overview

Running your database in a Docker container can help streamline your development process and ease deployment. Docker Hub provides numerous pre-made images for popular databases such as MySQL, PostgreSQL, and MongoDB.

Example: Using MySQL Image

To use a MySQL database, search for the official image on Docker Hub:

docker search mysql

Find the official image, and pull it:

docker pull mysql

Now, you can run a MySQL container. Specify the required environment variables, such as MYSQL_ROOT_PASSWORD, and optionally map the container's port to your host machine:

docker run --name some-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -p 3306:3306 -d mysql

This command creates a new container named some-mysql, sets the root password to my-secret-pw, and maps port 3306 on the host to port 3306 on the container.

To connect to the database from another container, use the --link flag:

docker run --name some-app --link some-mysql:mysql -d my-app

Example: Using PostgreSQL Image

For PostgreSQL, follow similar steps to those outlined above. First, search for the official image:

docker search postgres

Pull the image:

docker pull postgres

Run a PostgreSQL container, specifying environment variables such as POSTGRES_PASSWORD:

docker run --name some-postgres -e POSTGRES_PASSWORD=my-secret-pw -p 5432:5432 -d postgres

Link the container to another container to allow communication:

docker run --name some-app --link some-postgres:postgres -d my-app

Example: Using MongoDB Image

Running a MongoDB container with Docker follows a similar pattern as previous examples. Search for the official image:

docker search mongo

Pull the image:

docker pull mongo

Run a MongoDB container:

docker run --name some-mongo -p 27017:27017 -d mongo

Link the container to another container:

docker run --name some-app --link some-mongo:mongo -d my-app

Conclusion

Docker makes it easy to use third-party images for databases, streamlining your development process and ensuring a consistent environment for your applications. This guide demonstrated examples of using MySQL, PostgreSQL, and MongoDB, but many other database images are available on Docker Hub.