Networking is an important aspect of Docker that allows container to communicate with each other and with the outside network. Here is a detailed guide on how to connect and manage networks in Docker:
Default Bridge Network
Docker provides a default network called bridge for container. When creating a container without specifying a network, it automatically attaches to the default bridge network.
Containers on the same bridge network can communicate with each other using their internal IP addresses. Docker provides DNS resolution to allow container communication via domain names.
Container Linking
By using the --link option, you can link one container to another, enabling communication between them using the linked container's name or environment variables.
For example, when running a container from an image named webapp, you can link it to a MySQL container named mysql with the following command: docker run --name webapp --link mysql:mysql webapp-image
Custom Networks
You can create custom networks in Docker to allow containers within the same network to communicate.
Use the docker network create command to create a custom network. For example, to create a network named my-network, you can use the command: docker network create my-network
Attaching Container to Custom Networks
When creating a container, use the --network option to attach the container to a custom network.
For example, to attach a container to the "my-network" network, you can use the command: docker run --network my-network my-image
Connecting Container to the Host Network
Use the --publish or --publish-all options to connect container ports to ports on the host machine or to random ports on the host.
For example, to connect port 80 of a container to port 8080 on the host, you can use the command: docker run -p 8080:80 my-image
By utilizing the networking features in Docker, you can manage the connectivity and communication between container and networks in your Docker environment. This provides a flexible and scalable environment for your applications, allowing components within container to interact with each other and with the external network seamlessly.