docker-network-create - Man Page

You should create overlay networks with /24 blocks (the default), which limits you to 256 IP addresses, when you create networks using the default VIP-based endpoint-mode. This recommendation addresses limitations with swarm mode ⟨https://github.com/moby/moby/issues/30820⟩. If you need more than 256 IP addresses, do not increase the IP block size. You can either use dnsrr endpoint mode with an external load balancer, or use multiple smaller overlay networks. See Configure service discovery ⟨https://docs.docker.com/engine/swarm/networking/#configure-service-discovery⟩ for more information about different endpoint modes.

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 --driver=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. This example uses two /25 subnet mask to adhere to the current guidance of not having more than 256 IPs in a single overlay network. Each of the subnetworks has 126 usable addresses.

$ docker network create -d overlay \
  --subnet=192.168.10.0/25 \
  --subnet=192.168.20.0/25 \
  --gateway=192.168.10.100 \
  --gateway=192.168.20.100 \
  --aux-address="my-router=192.168.10.5" --aux-address="my-switch=192.168.10.6" \
  --aux-address="my-printer=192.168.20.5" --aux-address="my-nas=192.168.20.6" \
  my-multihost-network

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

When creating a custom network, the default network driver (i.e. bridge) has additional options that can be passed. The following are those options and the equivalent docker daemon flags used for docker0 bridge:

The following arguments can be passed to docker network create for any network driver, again with their approximate equivalents to docker daemon.

For example, let's use -o or --opt options to specify an IP address binding when publishing ports:

$ docker network create \
    -o "com.docker.network.bridge.host_binding_ipv4"="172.19.0.1" \
    simple-network

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.

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.driver.mtu=9216 \
  --opt encrypted=true \
  my-ingress-network

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

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

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