github.com/flavio/docker@v0.1.3-0.20170117145210-f63d1a6eec47/man/src/network/create.md (about) 1 Creates a new network. The `DRIVER` accepts `bridge` or `overlay` which are the 2 built-in network drivers. If you have installed a third party or your own custom 3 network driver you can specify that `DRIVER` here also. If you don't specify the 4 `--driver` option, the command automatically creates a `bridge` network for you. 5 When you install Docker Engine it creates a `bridge` network automatically. This 6 network corresponds to the `docker0` bridge that Engine has traditionally relied 7 on. When launch a new container with `docker run` it automatically connects to 8 this bridge network. You cannot remove this default bridge network but you can 9 create new ones using the `network create` command. 10 11 ```bash 12 $ docker network create -d bridge my-bridge-network 13 ``` 14 15 Bridge networks are isolated networks on a single Engine installation. If you 16 want to create a network that spans multiple Docker hosts each running an 17 Engine, you must create an `overlay` network. Unlike `bridge` networks overlay 18 networks require some pre-existing conditions before you can create one. These 19 conditions are: 20 21 * Access to a key-value store. Engine supports Consul, Etcd, and Zookeeper (Distributed store) key-value stores. 22 * A cluster of hosts with connectivity to the key-value store. 23 * A properly configured Engine `daemon` on each host in the cluster. 24 25 The `dockerd` options that support the `overlay` network are: 26 27 * `--cluster-store` 28 * `--cluster-store-opt` 29 * `--cluster-advertise` 30 31 To read more about these options and how to configure them, see ["*Get started 32 with multi-host 33 network*"](https://docs.docker.com/engine/userguide/networking/get-started-overlay/). 34 35 It is also a good idea, though not required, that you install Docker Swarm on to 36 manage the cluster that makes up your network. Swarm provides sophisticated 37 discovery and server management that can assist your implementation. 38 39 Once you have prepared the `overlay` network prerequisites you simply choose a 40 Docker host in the cluster and issue the following to create the network: 41 42 ```bash 43 $ docker network create -d overlay my-multihost-network 44 ``` 45 46 Network names must be unique. The Docker daemon attempts to identify naming 47 conflicts but this is not guaranteed. It is the user's responsibility to avoid 48 name conflicts. 49 50 ## Connect containers 51 52 When you start a container use the `--network` flag to connect it to a network. 53 This adds the `busybox` container to the `mynet` network. 54 55 ```bash 56 $ docker run -itd --network=mynet busybox 57 ``` 58 59 If you want to add a container to a network after the container is already 60 running use the `docker network connect` subcommand. 61 62 You can connect multiple containers to the same network. Once connected, the 63 containers can communicate using only another container's IP address or name. 64 For `overlay` networks or custom plugins that support multi-host connectivity, 65 containers connected to the same multi-host network but launched from different 66 Engines can also communicate in this way. 67 68 You can disconnect a container from a network using the `docker network 69 disconnect` command. 70 71 ## Specifying advanced options 72 73 When you create a network, Engine creates a non-overlapping subnetwork for the 74 network by default. This subnetwork is not a subdivision of an existing network. 75 It is purely for ip-addressing purposes. You can override this default and 76 specify subnetwork values directly using the `--subnet` option. On a 77 `bridge` network you can only create a single subnet: 78 79 ```bash 80 $ docker network create -d bridge --subnet=192.168.0.0/16 br0 81 ``` 82 83 Additionally, you also specify the `--gateway` `--ip-range` and `--aux-address` 84 options. 85 86 ```bash 87 $ docker network create \ 88 --driver=bridge \ 89 --subnet=172.28.0.0/16 \ 90 --ip-range=172.28.5.0/24 \ 91 --gateway=172.28.5.254 \ 92 br0 93 ``` 94 95 If you omit the `--gateway` flag the Engine selects one for you from inside a 96 preferred pool. For `overlay` networks and for network driver plugins that 97 support it you can create multiple subnetworks. 98 99 ```bash 100 $ docker network create -d overlay \ 101 --subnet=192.168.0.0/16 \ 102 --subnet=192.170.0.0/16 \ 103 --gateway=192.168.0.100 \ 104 --gateway=192.170.0.100 \ 105 --ip-range=192.168.1.0/24 \ 106 --aux-address="my-router=192.168.1.5" --aux-address="my-switch=192.168.1.6" \ 107 --aux-address="my-printer=192.170.1.5" --aux-address="my-nas=192.170.1.6" \ 108 my-multihost-network 109 ``` 110 111 Be sure that your subnetworks do not overlap. If they do, the network create 112 fails and Engine returns an error. 113 114 ### Network internal mode 115 116 By default, when you connect a container to an `overlay` network, Docker also 117 connects a bridge network to it to provide external connectivity. If you want 118 to create an externally isolated `overlay` network, you can specify the 119 `--internal` option.