Docker network

How to find the Container’s host ip

You need to find out the IP address of the container running in the host so you can, for example, connect to the web server running in it.

docker-machine is what is used on MacOSX and Windows.

Firstly, list your machines:

$ docker-machine ls

NAME      ACTIVE   DRIVER       STATE     URL                         SWARM
default   *        virtualbox   Running   tcp://192.168.99.100:2376

Then select one of the machines (the default one is called default) and:

$ docker-machine ip default

192.168.99.100

Creating a Docker network

docker network create app-backend

This command will create a simple bridged network called appBackend. No containers are attached to this network by default.

Listing Networks

docker network ls

This command lists all networks that have been created on the local Docker host. It includes the default bridge bridge network, the host host network, and the null null network. All containers by default are attached to the default bridge bridge network.

Add container to network

docker network connect app-backend myAwesomeApp-1

This command attaches the myAwesomeApp-1 container to the app-backend network. When you add a container to a user-defined network, the embedded DNS resolver (which is not a full-featured DNS server, and is not exportable) allows each container on the network to resolve each other container on the same network. This simple DNS resolver is not available on the default bridge bridge network.

Detach container from network

docker network disconnect app-backend myAwesomeApp-1

This command detaches the myAwesomeApp-1 container from the app-backend network. The container will no longer be able to communicate with other containers on the network it has been disconnected from, nor use the embedded DNS resolver to look up other containers on the network it has been detached from.

Remove a Docker network

docker network rm app-backend

This command removes the user-defined app-backend network from the Docker host. All containers on the network not otherwise connected via another network will lose communication with other containers. It is not possible to remove the default bridge bridge network, the host host network, or the null null network.

Inspect a Docker network

docker network inspect app-backend

This command will output details about the app-backend network.

The of the output of this command should look similar to:

[
    {
        "Name": "foo",
        "Id": "a0349d78c8fd7c16f5940bdbaf1adec8d8399b8309b2e8a969bd4e3226a6fc58",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": {},
            "Config": [
                {
                    "Subnet": "172.18.0.0/16",
                    "Gateway": "172.18.0.1/16"
                }
            ]
        },
        "Internal": false,
        "Containers": {},
        "Options": {},
        "Labels": {}
    }
]