Allow two Docker containers to communicate with each other

To allow two Docker containers to communicate with each other, you can use a Docker network. Here’s how to set it up:

Step 1: Create a Docker Network

First, create a user-defined network. This allows containers on the network to communicate with each other by their container names.

docker network create my_network

Step 2: Run Containers on the Same Network

When starting each container, specify the network you created.

For example:

docker run -d --name container1 --network my_network my_image1 docker run -d --name container2 --network my_network my_image2

Now, container1 and container2 are both on my_network and can communicate.

Step 3: Access Each Other by Container Name

Within container1, you can access container2 by its name, container2, and vice versa. For instance, you could use ping:

docker exec -it container1 ping container2

Or connect through a service port (e.g., for HTTP):

curl http://container2:port

Additional Tips:

• Ports: If your containers expose services on specific ports (e.g., HTTP on port 80), make sure those services are listening on the correct port within the container.
• DNS Resolution: Docker’s network handles the DNS resolution automatically, so using container names as hostnames works seamlessly in user-defined networks.
• Inspect Network: Run docker network inspect my_network to verify that both containers are connected.