github.com/vincentwoo/docker@v0.7.3-0.20160116130405-82401a4b13c0/docs/reference/commandline/network_create.md

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1 
10
11 # network create
12
13 Usage: docker network create [OPTIONS] NETWORK-NAME
14
15 Creates a new network with a name specified by the user
16
17 --aux-address=map[] Auxiliary ipv4 or ipv6 addresses used by network driver
18 -d --driver=DRIVER Driver to manage the Network bridge or overlay. The default is bridge.
19 --gateway=[] ipv4 or ipv6 Gateway for the master subnet
20 --help Print usage
21 --internal Restricts external access to the network
22 --ip-range=[] Allocate container ip from a sub-range
23 --ipam-driver=default IP Address Management Driver
24 -o --opt=map[] Set custom network plugin options
25 --ipam-opt=map[] Set custom IPAM plugin options
26 --subnet=[] Subnet in CIDR format that represents a network segment
27
28 Creates a new network. The `DRIVER` accepts `bridge` or `overlay` which are the
29 built-in network drivers. If you have installed a third party or your own custom
30 network driver you can specify that `DRIVER` here also. If you don't specify the
31 `--driver` option, the command automatically creates a `bridge` network for you.
32 When you install Docker Engine it creates a `bridge` network automatically. This
33 network corresponds to the `docker0` bridge that Engine has traditionally relied
34 on. When launch a new container with `docker run` it automatically connects to
35 this bridge network. You cannot remove this default bridge network but you can
36 create new ones using the `network create` command.
37
38 ```bash
39 $ docker network create -d bridge my-bridge-network
40 ```
41
42 Bridge networks are isolated networks on a single Engine installation. If you
43 want to create a network that spans multiple Docker hosts each running an
44 Engine, you must create an `overlay` network. Unlike `bridge` networks overlay
45 networks require some pre-existing conditions before you can create one. These
46 conditions are:
47
48 * Access to a key-value store. Engine supports Consul, Etcd, and ZooKeeper (Distributed store) key-value stores.
49 * A cluster of hosts with connectivity to the key-value store.
50 * A properly configured Engine `daemon` on each host in the cluster.
51
52 The `docker daemon` options that support the `overlay` network are:
53
54 * `--cluster-store`
55 * `--cluster-store-opt`
56 * `--cluster-advertise`
57
58 To read more about these options and how to configure them, see ["*Get started
59 with multi-host network*"](../../userguide/networking/get-started-overlay.md).
60
61 It is also a good idea, though not required, that you install Docker Swarm on to
62 manage the cluster that makes up your network. Swarm provides sophisticated
63 discovery and server management that can assist your implementation.
64
65 Once you have prepared the `overlay` network prerequisites you simply choose a
66 Docker host in the cluster and issue the following to create the network:
67
68 ```bash
69 $ docker network create -d overlay my-multihost-network
70 ```
71
72 Network names must be unique. The Docker daemon attempts to identify naming
73 conflicts but this is not guaranteed. It is the user's responsibility to avoid
74 name conflicts.
75
76 ## Connect containers
77
78 When you start a container use the `--net` flag to connect it to a network.
79 This adds the `busybox` container to the `mynet` network.
80
81 ```bash
82 $ docker run -itd --net=mynet busybox
83 ```
84
85 If you want to add a container to a network after the container is already
86 running use the `docker network connect` subcommand.
87
88 You can connect multiple containers to the same network. Once connected, the
89 containers can communicate using only another container's IP address or name.
90 For `overlay` networks or custom plugins that support multi-host connectivity,
91 containers connected to the same multi-host network but launched from different
92 Engines can also communicate in this way.
93
94 You can disconnect a container from a network using the `docker network
95 disconnect` command.
96
97 ## Specifying advanced options
98
99 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:
100
101 ```bash
102 docker network create -d --subnet=192.168.0.0/16
103 ```
104 Additionally, you also specify the `--gateway` `--ip-range` and `--aux-address` options.
105
106 ```bash
107 network create --driver=bridge --subnet=172.28.0.0/16 --ip-range=172.28.5.0/24 --gateway=172.28.5.254 br0
108 ```
109
110 If you omit the `--gateway` flag the Engine selects one for you from inside a
111 preferred pool. For `overlay` networks and for network driver plugins that
112 support it you can create multiple subnetworks.
113
114 ```bash
115 docker network create -d overlay
116 --subnet=192.168.0.0/16 --subnet=192.170.0.0/16
117 --gateway=192.168.0.100 --gateway=192.170.0.100
118 --ip-range=192.168.1.0/24
119 --aux-address a=192.168.1.5 --aux-address b=192.168.1.6
120 --aux-address a=192.170.1.5 --aux-address b=192.170.1.6
121 my-multihost-network
122 ```
123 Be sure that your subnetworks do not overlap. If they do, the network create fails and Engine returns an error.
124
125 ### Network internal mode
126
127 By default, when you connect a container to an `overlay` network, Docker also connects a bridge network to it to provide external connectivity.
128 If you want to create an externally isolated `overlay` network, you can specify the `--internal` option.
129
130 ## Related information
131
132 * [network inspect](network_inspect.md)
133 * [network connect](network_connect.md)
134 * [network disconnect](network_disconnect.md)
135 * [network ls](network_ls.md)
136 * [network rm](network_rm.md)
137 * [Understand Docker container networks](../../userguide/networking/dockernetworks.md)