docker network connect

Estimated reading time: 4 minutes

Description

Connect a container to a network

Usage

docker network connect [OPTIONS] NETWORK CONTAINER

Options

Name, shorthand	Default	Description
`--alias`		Add network-scoped alias for the container
`--ip`		IPv4 address (e.g., 172.30.100.104)
`--ip6`		IPv6 address (e.g., 2001:db8::33)
`--link`		Add link to another container
`--link-local-ip`		Add a link-local address for the container

Parent command

Command	Description
docker network	Manage networks

Command	Description
docker network connect	Connect a container to a network
docker network create	Create a network
docker network disconnect	Disconnect a container from a network
docker network inspect	Display detailed information on one or more networks
docker network ls	List networks
docker network prune	Remove all unused networks
docker network rm	Remove one or more networks

Extended description

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

$ docker network connect multi-host-network container1

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

$ docker run -itd --network=multi-host-network --ip 172.20.88.22 --ip6 2001:db8::8822 busybox

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 stopped container is restarted. If the IP address is no longer available, the container fails to start. One way to guarantee that the IP address is available is to specify an --ip-range when creating the network, and choose the static IP address(es) from outside that range. This ensures that the IP address is not given 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 another container’s IP address or name. For overlay networks or custom plugins that support multi-host connectivity, containers connected to the same multi-host network 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 be the same type. For example, you can connect a single container bridge and overlay networks.

Examples

$ docker network connect multi-host-network container1