docker network connect (2024)

Connects a container to a network. You can connect a container by nameor by ID. Once connected, the container can communicate with other containers inthe same network.

Options

Connect a running container to a network

$ docker network connect multi-host-network container1

Connect a container to a network when it starts

You can also use the docker run --network=<network-name> option to start acontainer and immediately connect it to a network.

$ docker run -itd --network=multi-host-network busybox

Specify the IP address a container will use on a given network (--ip)

You can specify the IP address you want to be assigned to the container's interface.

$ docker network connect --ip 10.10.36.122 multi-host-network container2

Use the legacy --link option (--link)

You can use --link option to link another container with a preferred alias.

$ docker network connect --link container1:c1 multi-host-network container2

Create a network alias for a container (--alias)

--alias option can be used to resolve the container by another name in the networkbeing connected to.

$ docker network connect --alias db --alias mysql multi-host-network container2

Network implications of stopping, pausing, or restarting containers

You can pause, restart, and stop containers that are connected to a network.A container connects to its configured networks when it runs.

If specified, the container's IP address(es) is reapplied when a stoppedcontainer is restarted. If the IP address is no longer available, the containerfails to start. One way to guarantee that the IP address is available isto specify an --ip-range when creating the network, and choose the static IPaddress(es) from outside that range. This ensures that the IP address is notgiven to another container while this container is not on the network.

$ docker network create --subnet 172.20.0.0/16 --ip-range 172.20.240.0/20 multi-host-network

$ docker network connect --ip 172.20.128.2 multi-host-network container2

To verify the container is connected, use the docker network inspect command.Use docker network disconnect to remove a container from the network.

Once connected in network, containers can communicate using only anothercontainer's IP address or name. For overlay networks or custom plugins thatsupport multi-host connectivity, containers connected to the same multi-hostnetwork but launched from different Engines can also communicate in this way.

You can connect a container to one or more networks. The networks need not bethe same type. For example, you can connect a single container bridge and overlaynetworks.