158 lines
7.2 KiB
Markdown
158 lines
7.2 KiB
Markdown
<!--[metadata]>
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+++
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title = "network create"
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description = "The network create command description and usage"
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keywords = ["network, create"]
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[menu.main]
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parent = "smn_cli"
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+++
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<![end-metadata]-->
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# network create
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Usage: docker network create [OPTIONS] NETWORK-NAME
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Creates a new network with a name specified by the user
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--aux-address=map[] Auxiliary ipv4 or ipv6 addresses used by network driver
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-d --driver=DRIVER Driver to manage the Network bridge or overlay. The default is bridge.
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--gateway=[] ipv4 or ipv6 Gateway for the master subnet
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--help Print usage
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--internal Restricts external access to the network
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--ip-range=[] Allocate container ip from a sub-range
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--ipam-driver=default IP Address Management Driver
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--ipam-opt=map[] Set custom IPAM driver specific options
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-o --opt=map[] Set custom driver specific options
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--subnet=[] Subnet in CIDR format that represents a network segment
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Creates a new network. The `DRIVER` accepts `bridge` or `overlay` which are the
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built-in network drivers. If you have installed a third party or your own custom
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network driver you can specify that `DRIVER` here also. If you don't specify the
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`--driver` option, the command automatically creates a `bridge` network for you.
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When you install Docker Engine it creates a `bridge` network automatically. This
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network corresponds to the `docker0` bridge that Engine has traditionally relied
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on. When launch a new container with `docker run` it automatically connects to
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this bridge network. You cannot remove this default bridge network but you can
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create new ones using the `network create` command.
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```bash
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$ docker network create -d bridge my-bridge-network
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```
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Bridge networks are isolated networks on a single Engine installation. If you
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want to create a network that spans multiple Docker hosts each running an
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Engine, you must create an `overlay` network. Unlike `bridge` networks overlay
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networks require some pre-existing conditions before you can create one. These
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conditions are:
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* Access to a key-value store. Engine supports Consul, Etcd, and ZooKeeper (Distributed store) key-value stores.
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* A cluster of hosts with connectivity to the key-value store.
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* A properly configured Engine `daemon` on each host in the cluster.
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The `docker daemon` options that support the `overlay` network are:
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* `--cluster-store`
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* `--cluster-store-opt`
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* `--cluster-advertise`
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To read more about these options and how to configure them, see ["*Get started
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with multi-host network*"](../../userguide/networking/get-started-overlay.md).
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It is also a good idea, though not required, that you install Docker Swarm on to
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manage the cluster that makes up your network. Swarm provides sophisticated
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discovery and server management that can assist your implementation.
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Once you have prepared the `overlay` network prerequisites you simply choose a
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Docker host in the cluster and issue the following to create the network:
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```bash
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$ docker network create -d overlay my-multihost-network
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```
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Network names must be unique. The Docker daemon attempts to identify naming
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conflicts but this is not guaranteed. It is the user's responsibility to avoid
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name conflicts.
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## Connect containers
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When you start a container use the `--net` flag to connect it to a network.
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This adds the `busybox` container to the `mynet` network.
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```bash
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$ docker run -itd --net=mynet busybox
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```
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If you want to add a container to a network after the container is already
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running use the `docker network connect` subcommand.
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You can connect multiple containers to the same network. Once connected, the
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containers can communicate using only another container's IP address or name.
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For `overlay` networks or custom plugins that support multi-host connectivity,
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containers connected to the same multi-host network but launched from different
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Engines can also communicate in this way.
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You can disconnect a container from a network using the `docker network
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disconnect` command.
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## Specifying advanced options
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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 the `--subnet` option. On a `bridge` network you can only create a single subnet:
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```bash
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docker network create -d --subnet=192.168.0.0/16
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```
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Additionally, you also specify the `--gateway` `--ip-range` and `--aux-address` options.
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```bash
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network create --driver=bridge --subnet=172.28.0.0/16 --ip-range=172.28.5.0/24 --gateway=172.28.5.254 br0
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```
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If you omit the `--gateway` flag the Engine selects one for you from inside a
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preferred pool. For `overlay` networks and for network driver plugins that
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support it you can create multiple subnetworks.
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```bash
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docker network create -d overlay
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--subnet=192.168.0.0/16 --subnet=192.170.0.0/16
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--gateway=192.168.0.100 --gateway=192.170.0.100
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--ip-range=192.168.1.0/24
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--aux-address a=192.168.1.5 --aux-address b=192.168.1.6
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--aux-address a=192.170.1.5 --aux-address b=192.170.1.6
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my-multihost-network
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```
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Be sure that your subnetworks do not overlap. If they do, the network create fails and Engine returns an error.
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# Bridge driver options
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When creating a custom network, the default network driver (i.e. `bridge`) has additional options that can be passed.
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The following are those options and the equivalent docker daemon flags used for docker0 bridge:
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| Option | Equivalent | Description |
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|--------------------------------------------------|-------------|-------------------------------------------------------|
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| `com.docker.network.bridge.name` | - | bridge name to be used when creating the Linux bridge |
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| `com.docker.network.bridge.enable_ip_masquerade` | `--ip-masq` | Enable IP masquerading |
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| `com.docker.network.bridge.enable_icc` | `--icc` | Enable or Disable Inter Container Connectivity |
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| `com.docker.network.bridge.host_binding_ipv4` | `--ip` | Default IP when binding container ports |
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| `com.docker.network.mtu` | `--mtu` | Set the containers network MTU |
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| `com.docker.network.enable_ipv6` | `--ipv6` | Enable IPv6 networking |
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For example, let's use `-o` or `--opt` options to specify an IP address binding when publishing ports:
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```bash
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docker network create -o "com.docker.network.bridge.host_binding_ipv4"="172.19.0.1" simple-network
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```
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### Network internal mode
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By default, when you connect a container to an `overlay` network, Docker also connects a bridge network to it to provide external connectivity.
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If you want to create an externally isolated `overlay` network, you can specify the `--internal` option.
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## Related information
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* [network inspect](network_inspect.md)
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* [network connect](network_connect.md)
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* [network disconnect](network_disconnect.md)
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* [network ls](network_ls.md)
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* [network rm](network_rm.md)
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* [Understand Docker container networks](../../userguide/networking/dockernetworks.md)
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