mirror of https://github.com/docker/cli.git
203 lines
8.6 KiB
Markdown
203 lines
8.6 KiB
Markdown
---
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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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---
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# network create
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```markdown
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Usage: docker network create [OPTIONS] NETWORK
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Create a network
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Options:
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--attachable Enable manual container attachment
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--aux-address value Auxiliary IPv4 or IPv6 addresses used by Network
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driver (default map[])
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-d, --driver string Driver to manage the Network (default "bridge")
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--gateway value IPv4 or IPv6 Gateway for the master subnet (default [])
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--help Print usage
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--internal Restrict external access to the network
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--ip-range value Allocate container ip from a sub-range (default [])
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--ipam-driver string IP Address Management Driver (default "default")
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--ipam-opt value Set IPAM driver specific options (default map[])
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--ipv6 Enable IPv6 networking
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--label value Set metadata on a network (default [])
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-o, --opt value Set driver specific options (default map[])
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--subnet value Subnet in CIDR format that represents a
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network segment (default [])
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```
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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 you 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 `dockerd` 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*"](https://docs.docker.com/engine/userguide/networking/get-started-overlay).
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While not required, it is a good idea to install Docker Swarm to
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manage the cluster that makes up your network. Swarm provides sophisticated
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discovery and server management tools 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 `--network` flag to connect it to a network.
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This example adds the `busybox` container to the `mynet` network:
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```bash
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$ docker run -itd --network=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
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network by default. This subnetwork is not a subdivision of an existing
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network. It is purely for ip-addressing purposes. You can override this default
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and specify subnetwork values directly using the `--subnet` option. On a
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`bridge` network you can only create a single subnet:
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```bash
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$ docker network create --driver=bridge --subnet=192.168.0.0/16 br0
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```
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Additionally, you also specify the `--gateway` `--ip-range` and `--aux-address`
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options.
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```bash
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$ docker network create \
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--driver=bridge \
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--subnet=172.28.0.0/16 \
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--ip-range=172.28.5.0/24 \
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--gateway=172.28.5.254 \
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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 \
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--subnet=192.170.0.0/16 \
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--gateway=192.168.0.100 \
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--gateway=192.170.0.100 \
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--ip-range=192.168.1.0/24 \
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--aux-address="my-router=192.168.1.5" --aux-address="my-switch=192.168.1.6" \
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--aux-address="my-printer=192.170.1.5" --aux-address="my-nas=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
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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
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additional options that can be passed. The following are those options and the
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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.driver.mtu` | `--mtu` | Set the containers network MTU |
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The following arguments can be passed to `docker network create` for any
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network driver, again with their approximate equivalents to `docker daemon`.
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| Argument | Equivalent | Description |
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|--------------|----------------|--------------------------------------------|
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| `--gateway` | - | IPv4 or IPv6 Gateway for the master subnet |
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| `--ip-range` | `--fixed-cidr` | Allocate IPs from a range |
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| `--internal` | - | Restrict external access to the network |
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| `--ipv6` | `--ipv6` | Enable IPv6 networking |
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| `--subnet` | `--bip` | Subnet for network |
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For example, let's use `-o` or `--opt` options to specify an IP address binding
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when publishing ports:
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```bash
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$ docker network create \
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-o "com.docker.network.bridge.host_binding_ipv4"="172.19.0.1" \
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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
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connects a bridge network to it to provide external connectivity. If you want
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to create an externally isolated `overlay` network, you can specify the
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`--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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* [network prune](network_prune.md)
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* [Understand Docker container networks](https://docs.docker.com/engine/userguide/networking/)
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