Docker Compose with Custom Network Example

  Docker Compose allows you to define multi-container applications and specify how they communicate with each other using Docker networks. B...

 Docker Compose allows you to define multi-container applications and specify how they communicate with each other using Docker networks. Below is an example of a Docker Compose file that defines two services (containers) and sets up a custom network for them to communicate:

version: '3'

services:
  webapp:
    image: nginx:latest
    container_name: webapp-container
    ports:
      - "80:80"
    networks:
      - my-network

  database:
    image: mysql:latest
    container_name: db-container
    environment:
      MYSQL_ROOT_PASSWORD: root_password
    networks:
      - my-network

networks:
  my-network:

In this Docker Compose file:

1. We define two services: webapp and database.

2. The webapp service uses the official Nginx image and maps port 80 from the container to port 80 on the host machine.

3. The database service uses the official MySQL image and sets the root password as an environment variable.

4. We define a custom network named my-network under the networks section.

5. Both services (webapp and database) are connected to the my-network network using the networks directive within their respective service definitions.

By placing both containers on the same custom network (my-network), they can communicate with each other using their service names as hostnames. For example, the webapp service can connect to the MySQL database using the hostname database.

To start these containers using Docker Compose, navigate to the directory containing the docker-compose.yml file and run:

docker-compose up -d

This will create and start the webapp-container and db-container containers on the my-network network, allowing them to communicate.

Inside the webapp container, you can use the hostname database to connect to the MySQL database. For example, in a configuration file or code that requires the MySQL host:

# MySQL connection settings
host: database
port: 3306
user: root
password: root_password

This setup simplifies container communication and isolates the services within the same network while keeping them separate from other containers running on the host machine.