docker network connect

Estimated reading time:

3 minutes

Description

Connect a container to a network

Usage

docker network connect [OPTIONS] NETWORK CONTAINER

Options

Name, shorthandDefaultDescription--aliasAdd network-scoped alias for the container--ipIPv4 address (e.g., 172.30.100.104)--ip6IPv6 address (e.g., 2001:db8::33)--linkAdd link to another container--link-local-ipAdd a link-local address for the container

Parent command

CommandDescriptiondocker networkManage networks

Related commands

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.

Examples

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 a container 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

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

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 option can be used to resolve the container by another name in the network
being 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 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.