How to create and manage Docker networks

Docker provides networking capabilities that allow containers to communicate with each other, host systems, and external networks. Docker networks are used to isolate containerized applications and provide them with their own network environment.

Here’s a step-by-step guide on how to create and manage docker networks:

Step 1: Create a Docker network

We can create a Docker network using the docker network create command, using the network name we need to connect to. For example, to create an example network named network_example, we can run the following command:

docker network create network_example

Step 2: List all Docker networks

We can list all the Docker networks on our system using the docker network ls command. It will display the names and types of all currently available networks.

docker network ls

Step 3: Inspect the Docker network

We can check the details of a specific Docker network using the docker network inspect command followed by the network name. This will give us information about the network configuration, containers connected to the network, and other relevant details.

docker network inspect network_example

Step 4: Connect containers to a Docker network

We can connect a container to a specific Docker network using the docker network connect command followed by the network name and the name or ID of the container we want to connect to. For example, to connect a container named container_example to the network network_example, we can run the following command:

docker network connect network_example container_example

Step 5: Disconnect containers from the Docker network

We can disconnect a container from the Docker network by using the docker network disconnect command followed by the network name and the name or ID of the container we want to disconnect. For example, to disconnect the container container_example from the network network_example, we can run the following command:

docker network disconnect network_example container_example

Step 6: Remove a Docker network

We can remove a docker network using the docker network rm command followed by the network name. We cannot delete a network to which active containers are attached. Disconnect all containers from the network before removing them.

docker network rm network_example

Step 7: Use Docker networks in Docker compose

If we use docker-compose to define and manage multi-container applications, we can define networks in the docker-compose.yml file using the networks section. For example, let’s look at the code below:

In this example, a Docker network called network_example is defined in the networks section, and the web service is connected to this network using the network key under the service definition.

Docker networks provide powerful networking capabilities for Docker containers, allowing us to isolate and manage their network environment. By leveraging Docker networks, we can build complex multi-container applications that can communicate with each other and with external networks in a controlled and orchestrated manner.