docker network create
Estimated reading time: 9 minutesDescription
Create a network
Usage
docker network create [OPTIONS] NETWORK
Options
Name, shorthand | 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 copying the configuration |
|
--config-only |
API 1.30+ Create a configuration only network |
|
--driver , -d |
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 IPv6 networking | |
--label |
Set metadata on a network | |
--opt , -o |
Set driver specific options | |
--scope |
API 1.30+ Control the network’s scope |
|
--subnet |
Subnet in CIDR format that represents a network segment |
Parent command
Command | Description |
---|---|
docker network | Manage networks |
Related commands
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
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”.
While not required, it is a good idea to install Docker Swarm to manage the cluster that makes up your network. Swarm provides sophisticated discovery and server management tools 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.
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.
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
Engines 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, 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=192.168.1.0/25 \
--subnet=192.170.2.0/25 \
--gateway=192.168.1.100 \
--gateway=192.170.2.100 \
--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.
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 |
The following arguments can be passed to docker network create
for any
network driver, again with their approximate equivalents to docker daemon
.
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 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
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.driver.mtu=9216 \
--opt encrypted=true \
my-ingress-network