Ubuntu Manpage: docker-network-create

Provided by: docker.io_18.09.7-0ubuntu1~16.04.7_amd64

NAME

       docker-network-create - Create a network

SYNOPSIS

       docker network create [OPTIONS] NETWORK

DESCRIPTION

Creates a new network. The DRIVER accepts bridge or overlay which are the built-in network
drivers. If you have installed a third party or your own custom network driver you can
specify that DRIVER here also. If you don't specify the --driver option, the command
automatically creates a bridge network for you. When you install Docker Engine it creates
a bridge network automatically. This network corresponds to the docker0 bridge that Engine
has traditionally relied on. When you launch a new container with docker run it
automatically connects to this bridge network. You cannot remove this default bridge
network but you can create new ones using the network create command.

$ docker network create -d bridge my-bridge-network

Bridge networks are isolated networks on a single Engine installation. If you want to
create a network that spans multiple Docker hosts each running an Engine, you must create
an overlay network. Unlike bridge networks overlay networks require some pre-existing
conditions before you can create one. These conditions are:

• Access to a key-value store. Engine supports Consul, Etcd, and Zookeeper
(Distributed store) key-value stores.

• A cluster of hosts with connectivity to the key-value store.

• A properly configured Engine daemon on each host in the cluster.

The dockerd options that support the overlay network are:

• --cluster-store

• --cluster-store-opt

• --cluster-advertise

To read more about these options and how to configure them, see "Get started with
multi-host network" ⟨https://docs.docker.com/engine/userguide/networking/get-started-
overlay/⟩.

It is also a good idea, though not required, that you install Docker Swarm on to manage
the cluster that makes up your network. Swarm provides sophisticated discovery and server
management that can assist your implementation.

Once you have prepared the overlay network prerequisites you simply choose a Docker host
in the cluster and issue the following to create the network:

$ docker network create -d overlay my-multihost-network

Network names must be unique. The Docker daemon attempts to identify naming conflicts but
this is not guaranteed. It is the user's responsibility to avoid name conflicts.

Connect containers

       When you start a container use the --network flag to connect it to a network.  This adds
       the busybox container to the mynet network.

              $ docker run -itd --network=mynet busybox

       If you want to add a container to a network after the container is already running use the
       docker network connect subcommand.

       You can connect multiple containers to the same network. Once connected, the 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 disconnect a container from a network using the docker network disconnect command.

Specifying advanced options

When you create a network, Engine creates a non-overlapping subnetwork for the network by
default. This subnetwork is not a subdivision of an existing network. It is purely for
ip-addressing purposes. You can override this default and specify subnetwork values
directly using the --subnet option. On a bridge network you can only create a single
subnet:

$ docker network create -d bridge --subnet=192.168.0.0/16 br0

Additionally, you also specify the --gateway --ip-range and --aux-address options.

$ docker network create \
--driver=bridge \
--subnet=172.28.0.0/16 \
--ip-range=172.28.5.0/24 \
--gateway=172.28.5.254 \
br0

If you omit the --gateway flag the Engine selects one for you from inside a preferred
pool. For overlay networks and for network driver plugins that support it you can create
multiple subnetworks.

$ docker network create -d overlay \
--subnet=192.168.0.0/16 \
--subnet=192.170.0.0/16 \
--gateway=192.168.0.100 \
--gateway=192.170.0.100 \
--ip-range=192.168.1.0/24 \
--aux-address="my-router=192.168.1.5" --aux-address="my-switch=192.168.1.6" \
--aux-address="my-printer=192.170.1.5" --aux-address="my-nas=192.170.1.6" \
my-multihost-network

Be sure that your subnetworks do not overlap. If they do, the network create fails and
Engine returns an error.

Network internal mode
By default, when you connect a container to an overlay network, Docker also connects a
bridge network to it to provide external connectivity. If you want to create an externally
isolated overlay network, you can specify the --internal option.

Network ingress mode
You can create the network which will be used to provide the routing-mesh in the swarm
cluster. You do so by specifying --ingress when creating the network. Only one ingress
network can be created at the time. The network can be removed only if no services depend
on it. Any option available when creating an overlay network is also available when
creating the ingress network, besides the --attachable option.

$ docker network create -d overlay \
--subnet=10.11.0.0/16 \
--ingress \
--opt com.docker.network.mtu=9216 \
--opt encrypted=true \
my-ingress-network

Run services on predefined networks
You can create services on the predefined docker networks bridge and host.

$ docker service create --name my-service \
--network host \
--replicas 2 \
busybox top

Swarm networks with local scope drivers
You can create a swarm network with local scope network drivers. You do so by promoting
the network scope to swarm during the creation of the network. You will then be able to
use this network when creating services.

$ docker network create -d bridge \
--scope swarm \
--attachable \
swarm-network

For network drivers which provide connectivity across hosts (ex. macvlan), if node
specific configurations are needed in order to plumb the network on each host, you will
supply that configuration via a configuration only network. When you create the swarm
scoped network, you will then specify the name of the network which contains the
configuration.

node1$ docker network create --config-only --subnet 192.168.100.0/24 --gateway 192.168.100.115 mv-config
node2$ docker network create --config-only --subnet 192.168.200.0/24 --gateway 192.168.200.202 mv-config
node1$ docker network create -d macvlan --scope swarm --config-from mv-config --attachable swarm-network

OPTIONS