docker network create
Description | Create a network |
---|---|
Usage | 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 Docker 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 Docker Engine installation. If you
want to create a network that spans multiple Docker hosts each running Docker
Engine, you must enable Swarm mode, and create an overlay
network. To read more
about overlay networks with Swarm mode, see
"use overlay networks".
Once you have enabled swarm mode, you can create a swarm-scoped overlay network:
$ docker network create --scope=swarm --attachable -d overlay my-multihost-network
By default, swarm-scoped networks do not allow manually started containers to be attached. This restriction is added to prevent someone that has access to a non-manager node in the swarm cluster from running a container that is able to access the network stack of a swarm service.
The --attachable
option used in the example above disables this restriction,
and allows for both swarm services and manually started containers to attach to
the overlay 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.
Overlay network limitations
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. 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
for more information about different endpoint modes.
Options
Option | Default | Description |
---|---|---|
--attachable | API 1.25+ Enable manual container attachment | |
--aux-address | Auxiliary IPv4 or IPv6 addresses used by Network driver | |
--config-from | API 1.30+ The network from which to copy the configuration | |
--config-only | API 1.30+ Create a configuration only network | |
-d, --driver | bridge | Driver to manage the Network |
--gateway | IPv4 or IPv6 Gateway for the master subnet | |
--ingress | API 1.29+ Create swarm routing-mesh network | |
--internal | Restrict external access to the network | |
--ip-range | Allocate container ip from a sub-range | |
--ipam-driver | IP Address Management Driver | |
--ipam-opt | Set IPAM driver specific options | |
--ipv6 | Enable or disable IPv6 networking | |
--label | Set metadata on a network | |
-o, --opt | Set driver specific options | |
--scope | API 1.30+ Control the network's scope | |
--subnet | Subnet in CIDR format that represents a network segment |
Examples
Connect containers
When you start a container, use the --network
flag to connect it to a network.
This example 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
daemons can also communicate in this way.
You can disconnect a container from a network using the docker network disconnect
command.
Specify advanced options
When you create a network, Docker 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, Docker 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 Docker Engine returns an error.
Bridge driver options
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:
Option | Equivalent | Description |
---|---|---|
com.docker.network.bridge.name | - | Bridge name to be used when creating the Linux bridge |
com.docker.network.bridge.enable_ip_masquerade | --ip-masq | Enable IP masquerading |
com.docker.network.bridge.enable_icc | --icc | Enable or Disable Inter Container Connectivity |
com.docker.network.bridge.host_binding_ipv4 | --ip | Default IP when binding container ports |
com.docker.network.driver.mtu | --mtu | Set the containers network MTU |
com.docker.network.container_iface_prefix | - | Set a custom prefix for container interfaces |
The following arguments can be passed to docker network create
for any
network driver, again with their approximate equivalents to Docker daemon
flags used for the docker0 bridge:
Argument | Equivalent | Description |
---|---|---|
--gateway | - | IPv4 or IPv6 Gateway for the master subnet |
--ip-range | --fixed-cidr | Allocate IPs from a range |
--internal | - | Restrict external access to the network |
--ipv6 | --ipv6 | Enable or disable IPv6 networking |
--subnet | --bip | Subnet for network |
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
Network internal mode (--internal)
Containers on an internal network may communicate between each other, but not with any other network, as no default route is configured and firewall rules are set up to drop all traffic to or from other networks. Communication with the gateway IP address (and thus appropriately configured host services) is possible, and the host may communicate with any container IP directly.
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 (--ingress)
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
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