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Merge pull request #25135 from sfsmithcha/add_overlay_networking_note

Browse source 
per @mavenugo , merging after addressing his comments:
add swarm mode overlay networking security model
This commit is contained in:
Charles Smith 2016-08-12 13:25:07 -07:00 committed by GitHub
commit ccf3dd85f0
19 changed files with 735 additions and 46 deletions
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2
docs/reference/commandline/network_connect.md
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@ -93,5 +93,5 @@ You can connect a container to one or more networks. The networks need not be th
* [network disconnect](network_disconnect.md)
* [network ls](network_ls.md)
* [network rm](network_rm.md)
* [Understand Docker container networks](../../userguide/networking/dockernetworks.md)
* [Understand Docker container networks](../../userguide/networking/index.md)
* [Work with networks](../../userguide/networking/work-with-networks.md)

2
docs/reference/commandline/network_create.md
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@ -192,4 +192,4 @@ to create an externally isolated `overlay` network, you can specify the
* [network disconnect](network_disconnect.md)
* [network ls](network_ls.md)
* [network rm](network_rm.md)
* [Understand Docker container networks](../../userguide/networking/dockernetworks.md)
* [Understand Docker container networks](../../userguide/networking/index.md)

2
docs/reference/commandline/network_disconnect.md
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@ -34,4 +34,4 @@ Disconnects a container from a network. The container must be running to disconn
* [network create](network_create.md)
* [network ls](network_ls.md)
* [network rm](network_rm.md)
* [Understand Docker container networks](../../userguide/networking/dockernetworks.md)
* [Understand Docker container networks](../../userguide/networking/index.md)

2
docs/reference/commandline/network_inspect.md
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@ -119,4 +119,4 @@ $ docker network inspect simple-network
* [network create](network_create.md)
* [network ls](network_ls.md)
* [network rm](network_rm.md)
* [Understand Docker container networks](../../userguide/networking/dockernetworks.md)
* [Understand Docker container networks](../../userguide/networking/index.md)

2
docs/reference/commandline/network_ls.md
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@ -209,4 +209,4 @@ d1584f8dc718: host
* [network create](network_create.md)
* [network inspect](network_inspect.md)
* [network rm](network_rm.md)
* [Understand Docker container networks](../../userguide/networking/dockernetworks.md)
* [Understand Docker container networks](../../userguide/networking/index.md)

2
docs/reference/commandline/network_rm.md
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@ -50,4 +50,4 @@ deletion.
* [network create](network_create.md)
* [network ls](network_ls.md)
* [network inspect](network_inspect.md)
* [Understand Docker container networks](../../userguide/networking/dockernetworks.md)
* [Understand Docker container networks](../../userguide/networking/index.md)

1
docs/security/security.md
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@ -272,3 +272,4 @@ pull requests, and communicate via the mailing list.
* [Seccomp security profiles for Docker](../security/seccomp.md)
* [AppArmor security profiles for Docker](../security/apparmor.md)
* [On the Security of Containers (2014)](https://medium.com/@ewindisch/on-the-security-of-containers-2c60ffe25a9e)
* [Docker swarm mode overlay network security model](../userguide/networking/overlay-security-model.md)

2
docs/userguide/index.md
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@ -43,7 +43,7 @@ This guide helps users learn how to use Docker Engine.
## Configure networks
- [Understand Docker container networks](networking/dockernetworks.md)
- [Understand Docker container networks](networking/index.md)
- [Embedded DNS server in user-defined networks](networking/configure-dns.md)
- [Get started with multi-host networking](networking/get-started-overlay.md)
- [Work with network commands](networking/work-with-networks.md)

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docs/userguide/networking/default_network/binding.md
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@ -12,7 +12,7 @@ parent = "smn_networking_def"
The information in this section explains binding container ports within the Docker default bridge. This is a `bridge` network named `bridge` created automatically when you install Docker.
> **Note**: The [Docker networks feature](../dockernetworks.md) allows you to
> **Note**: The [Docker networks feature](../index.md) allows you to
create user-defined networks in addition to the default bridge network.
By default Docker containers can make connections to the outside world, but the
@ -100,6 +100,6 @@ address: this alternative is preferred for performance reasons.
## Related information
- [Understand Docker container networks](../dockernetworks.md)
- [Understand Docker container networks](../index.md)
- [Work with network commands](../work-with-networks.md)
- [Legacy container links](dockerlinks.md)

2
docs/userguide/networking/default_network/build-bridges.md
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@ -14,7 +14,7 @@ This section explains how to build your own bridge to replace the Docker default
bridge. This is a `bridge` network named `bridge` created automatically when you
install Docker.
> **Note**: The [Docker networks feature](../dockernetworks.md) allows you to
> **Note**: The [Docker networks feature](../index.md) allows you to
create user-defined networks in addition to the default bridge network.
You can set up your own bridge before starting Docker and use `-b BRIDGE` or

2
docs/userguide/networking/default_network/configure-dns.md
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@ -14,7 +14,7 @@ The information in this section explains configuring container DNS within
the Docker default bridge. This is a `bridge` network named `bridge` created
automatically when you install Docker.
> **Note**: The [Docker networks feature](../dockernetworks.md) allows you to create user-defined networks in addition to the default bridge network. Please refer to the [Docker Embedded DNS](../configure-dns.md) section for more information on DNS configurations in user-defined networks.
> **Note**: The [Docker networks feature](../index.md) allows you to create user-defined networks in addition to the default bridge network. Please refer to the [Docker Embedded DNS](../configure-dns.md) section for more information on DNS configurations in user-defined networks.
How can Docker supply each container with a hostname and DNS configuration, without having to build a custom image with the hostname written inside? Its trick is to overlay three crucial `/etc` files inside the container with virtual files where it can write fresh information. You can see this by running `mount` inside a container:

2
docs/userguide/networking/default_network/container-communication.md
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@ -14,7 +14,7 @@ The information in this section explains container communication within the
Docker default bridge. This is a `bridge` network named `bridge` created
automatically when you install Docker.
**Note**: The [Docker networks feature](../dockernetworks.md) allows you to create user-defined networks in addition to the default bridge network.
**Note**: The [Docker networks feature](../index.md) allows you to create user-defined networks in addition to the default bridge network.
## Communicating to the outside world

2
docs/userguide/networking/default_network/custom-docker0.md
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@ -12,7 +12,7 @@ parent = "smn_networking_def"
The information in this section explains how to customize the Docker default bridge. This is a `bridge` network named `bridge` created automatically when you install Docker.
**Note**: The [Docker networks feature](../dockernetworks.md) allows you to create user-defined networks in addition to the default bridge network.
**Note**: The [Docker networks feature](../index.md) allows you to create user-defined networks in addition to the default bridge network.
By default, the Docker server creates and configures the host system's `docker0` interface as an _Ethernet bridge_ inside the Linux kernel that can pass packets back and forth between other physical or virtual network interfaces so that they behave as a single Ethernet network.

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docs/userguide/networking/default_network/dockerlinks.md
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@ -13,7 +13,7 @@ weight=-2
The information in this section explains legacy container links within the Docker default bridge. This is a `bridge` network named `bridge` created automatically when you install Docker.
Before the [Docker networks feature](../dockernetworks.md), you could use the
Before the [Docker networks feature](../index.md), you could use the
Docker link feature to allow containers to discover each other and securely
transfer information about one container to another container. With the
introduction of the Docker networks feature, you can still create links but they

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docs/userguide/networking/get-started-overlay.md
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@ -14,19 +14,69 @@ weight=-3
This article uses an example to explain the basics of creating a multi-host
network. Docker Engine supports multi-host networking out-of-the-box through the
`overlay` network driver. Unlike `bridge` networks, overlay networks require
some pre-existing conditions before you can create one. These conditions are:
some pre-existing conditions before you can create one:
* Access to a key-value store. Docker supports Consul, Etcd, and ZooKeeper (Distributed store) key-value stores.
* [Docker Engine running in swarm mode](#overlay-networking-and-swarm-mode)
OR
* [A cluster of hosts using a key value store](#overlay-networking-with-an-external-key-value-store)
## Overlay networking and swarm mode
Using docker engine running in [swarm mode](../../swarm/swarm-mode.md), you can create an overlay network on a manager node.
The swarm makes the overlay network available only to nodes in the swarm that
require it for a service. When you create a service that uses an overlay
network, the manager node automatically extends the overlay network to nodes
that run service tasks.
To learn more about running Docker Engine in swarm mode, refer to the
[Swarm mode overview](../../swarm/index.md).
The example below shows how to create a network and use it for a service from a manager node in the swarm:
```bash
# Create an overlay network `my-multi-host-network`.
$ docker network create \
--driver overlay \
--subnet 10.0.9.0/24 \
my-multi-host-network
400g6bwzd68jizzdx5pgyoe95
# Create an nginx service and extend the my-multi-host-network to nodes where
# the service's tasks run.
$ $ docker service create --replicas 2 --network my-multi-host-network --name my-web nginx
716thylsndqma81j6kkkb5aus
```
Overlay networks for a swarm are not available to unmanaged containers. For more information refer to [Docker swarm mode overlay network security model](overlay-security-model.md).
## Overlay networking with an external key-value store
To use an Docker engine with an external key-value store, you need the
following:
* Access to the key-value store. Docker 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.
* Hosts within the cluster must have unique hostnames because the key-value store uses the hostnames to identify cluster members.
* Hosts within the cluster must have unique hostnames because the key-value
store uses the hostnames to identify cluster members.
Though Docker Machine and Docker Swarm are not mandatory to experience Docker
multi-host networking, this example uses them to illustrate how they are
integrated. You'll use Machine to create both the key-value store
server and the host cluster. This example creates a Swarm cluster.
multi-host networking with a key-value store, this example uses them to
illustrate how they are integrated. You'll use Machine to create both the
key-value store server and the host cluster. This example creates a Swarm
cluster.
## Prerequisites
>**Note:** Docker Engine running in swarm mode is not compatible with networking
with an external key-value store.
### Prerequisites
Before you begin, make sure you have a system on your network with the latest
version of Docker Engine and Docker Machine installed. The example also relies
@ -37,7 +87,7 @@ If you have not already done so, make sure you upgrade Docker Engine and Docker
Machine to the latest versions.
## Step 1: Set up a key-value store
### Set up a key-value store
An overlay network requires a key-value store. The key-value store holds
information about the network state which includes discovery, networks,
@ -80,7 +130,7 @@ key-value stores. This example uses Consul.
Keep your terminal open and move onto the next step.
## Step 2: Create a Swarm cluster
### Create a Swarm cluster
In this step, you use `docker-machine` to provision the hosts for your network.
At this point, you won't actually create the network. You'll create several
@ -123,7 +173,7 @@ At this point you have a set of hosts running on your network. You are ready to
Leave your terminal open and go onto the next step.
## Step 3: Create the overlay Network
### Create the overlay Network
To create an overlay network
@ -213,7 +263,7 @@ To create an overlay network
Both agents report they have the `my-net` network with the `6b07d0be843f` ID.
You now have a multi-host container network running!
## Step 4: Run an application on your Network
### Run an application on your Network
Once your network is created, you can start a container on any of the hosts and it automatically is part of the network.
@ -263,7 +313,7 @@ Once your network is created, you can start a container on any of the hosts and
</html>
- 100% |*******************************| 612 0:00:00 ETA
## Step 5: Check external connectivity
### Check external connectivity
As you've seen, Docker's built-in overlay network driver provides out-of-the-box
connectivity between the containers on multiple hosts within the same network.
@ -326,7 +376,7 @@ to have external connectivity outside of their cluster.
the `my-net` overlay network. While the `eth1` interface represents the
container interface that is connected to the `docker_gwbridge` network.
## Step 6: Extra Credit with Docker Compose
### Extra Credit with Docker Compose
Please refer to the Networking feature introduced in [Compose V2 format]
(https://docs.docker.com/compose/networking/) and execute the
@ -334,7 +384,7 @@ multi-host networking scenario in the Swarm cluster used above.
## Related information
* [Understand Docker container networks](dockernetworks.md)
* [Understand Docker container networks](index.md)
* [Work with network commands](work-with-networks.md)
* [Docker Swarm overview](https://docs.docker.com/swarm)
* [Docker Machine overview](https://docs.docker.com/machine)

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@ -1,21 +1,571 @@
<!--[metadata]>
+++
title = "Network configuration"
description = "Docker networking feature is introduced"
keywords = ["network, networking, bridge, docker, documentation"]
aliases=[
"/engine/userguide/networking/dockernetworks/"
]
title = "Docker container networking"
description = "How do we connect docker containers within and across hosts ?"
keywords = ["Examples, Usage, network, docker, documentation, user guide, multihost, cluster"]
[menu.main]
identifier="smn_networking"
parent= "engine_guide"
weight=7
identifier="networking_index"
parent = "smn_networking"
weight = -5
+++
<![end-metadata]-->
# Docker networks feature overview
# Understand Docker container networks
This sections explains how to use the Docker networks feature. This feature allows users to define their own networks and connect containers to them. Using this feature you can create a network on a single host or a network that spans across multiple hosts.
This section provides an overview of the default networking behavior that Docker
Engine delivers natively. It describes the type of networks created by default
and how to create your own, user-defined networks. It also describes the
resources required to create networks on a single host or across a cluster of
hosts.
## Default Networks
When you install Docker, it creates three networks automatically. You can list
these networks using the `docker network ls` command:
```
$ docker network ls
NETWORK ID NAME DRIVER
7fca4eb8c647 bridge bridge
9f904ee27bf5 none null
cf03ee007fb4 host host
```
Historically, these three networks are part of Docker's implementation. When
you run a container you can use the `--network` flag to specify which network you
want to run a container on. These three networks are still available to you.
The `bridge` network represents the `docker0` network present in all Docker
installations. Unless you specify otherwise with the `docker run
--network=<NETWORK>` option, the Docker daemon connects containers to this network
by default. You can see this bridge as part of a host's network stack by using
the `ifconfig` command on the host.
```
$ ifconfig
docker0 Link encap:Ethernet HWaddr 02:42:47:bc:3a:eb
inet addr:172.17.0.1 Bcast:0.0.0.0 Mask:255.255.0.0
inet6 addr: fe80::42:47ff:febc:3aeb/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:9001 Metric:1
RX packets:17 errors:0 dropped:0 overruns:0 frame:0
TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1100 (1.1 KB) TX bytes:648 (648.0 B)
```
The `none` network adds a container to a container-specific network stack. That container lacks a network interface. Attaching to such a container and looking at its stack you see this:
```
$ docker attach nonenetcontainer
root@0cb243cd1293:/# cat /etc/hosts
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
root@0cb243cd1293:/# ifconfig
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
root@0cb243cd1293:/#
```
>**Note**: You can detach from the container and leave it running with `CTRL-p CTRL-q`.
The `host` network adds a container on the hosts network stack. You'll find the
network configuration inside the container is identical to the host.
With the exception of the `bridge` network, you really don't need to
interact with these default networks. While you can list and inspect them, you
cannot remove them. They are required by your Docker installation. However, you
can add your own user-defined networks and these you can remove when you no
longer need them. Before you learn more about creating your own networks, it is
worth looking at the default `bridge` network a bit.
### The default bridge network in detail
The default `bridge` network is present on all Docker hosts. The `docker network inspect`
command returns information about a network:
```
$ docker network inspect bridge
[
{
"Name": "bridge",
"Id": "f7ab26d71dbd6f557852c7156ae0574bbf62c42f539b50c8ebde0f728a253b6f",
"Scope": "local",
"Driver": "bridge",
"IPAM": {
"Driver": "default",
"Config": [
{
"Subnet": "172.17.0.1/16",
"Gateway": "172.17.0.1"
}
]
},
"Containers": {},
"Options": {
"com.docker.network.bridge.default_bridge": "true",
"com.docker.network.bridge.enable_icc": "true",
"com.docker.network.bridge.enable_ip_masquerade": "true",
"com.docker.network.bridge.host_binding_ipv4": "0.0.0.0",
"com.docker.network.bridge.name": "docker0",
"com.docker.network.driver.mtu": "9001"
}
}
]
```
The Engine automatically creates a `Subnet` and `Gateway` to the network.
The `docker run` command automatically adds new containers to this network.
```
$ docker run -itd --name=container1 busybox
3386a527aa08b37ea9232cbcace2d2458d49f44bb05a6b775fba7ddd40d8f92c
$ docker run -itd --name=container2 busybox
94447ca479852d29aeddca75c28f7104df3c3196d7b6d83061879e339946805c
```
Inspecting the `bridge` network again after starting two containers shows both newly launched containers in the network. Their ids show up in the "Containers" section of `docker network inspect`:
```
$ docker network inspect bridge
{[
{
"Name": "bridge",
"Id": "f7ab26d71dbd6f557852c7156ae0574bbf62c42f539b50c8ebde0f728a253b6f",
"Scope": "local",
"Driver": "bridge",
"IPAM": {
"Driver": "default",
"Config": [
{
"Subnet": "172.17.0.1/16",
"Gateway": "172.17.0.1"
}
]
},
"Containers": {
"3386a527aa08b37ea9232cbcace2d2458d49f44bb05a6b775fba7ddd40d8f92c": {
"EndpointID": "647c12443e91faf0fd508b6edfe59c30b642abb60dfab890b4bdccee38750bc1",
"MacAddress": "02:42:ac:11:00:02",
"IPv4Address": "172.17.0.2/16",
"IPv6Address": ""
},
"94447ca479852d29aeddca75c28f7104df3c3196d7b6d83061879e339946805c": {
"EndpointID": "b047d090f446ac49747d3c37d63e4307be745876db7f0ceef7b311cbba615f48",
"MacAddress": "02:42:ac:11:00:03",
"IPv4Address": "172.17.0.3/16",
"IPv6Address": ""
}
},
"Options": {
"com.docker.network.bridge.default_bridge": "true",
"com.docker.network.bridge.enable_icc": "true",
"com.docker.network.bridge.enable_ip_masquerade": "true",
"com.docker.network.bridge.host_binding_ipv4": "0.0.0.0",
"com.docker.network.bridge.name": "docker0",
"com.docker.network.driver.mtu": "9001"
}
}
]
```
The `docker network inspect` command above shows all the connected containers and their network resources on a given network. Containers in this default network are able to communicate with each other using IP addresses. Docker does not support automatic service discovery on the default bridge network. If you want to communicate with container names in this default bridge network, you must connect the containers via the legacy `docker run --link` option.
You can `attach` to a running `container` and investigate its configuration:
```
$ docker attach container1
root@0cb243cd1293:/# ifconfig
ifconfig
eth0 Link encap:Ethernet HWaddr 02:42:AC:11:00:02
inet addr:172.17.0.2 Bcast:0.0.0.0 Mask:255.255.0.0
inet6 addr: fe80::42:acff:fe11:2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:9001 Metric:1
RX packets:16 errors:0 dropped:0 overruns:0 frame:0
TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1296 (1.2 KiB) TX bytes:648 (648.0 B)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
```
Then use `ping`to send three ICMP requests and test the connectivity of the
containers on this `bridge` network.
```
root@0cb243cd1293:/# ping -w3 172.17.0.3
PING 172.17.0.3 (172.17.0.3): 56 data bytes
64 bytes from 172.17.0.3: seq=0 ttl=64 time=0.096 ms
64 bytes from 172.17.0.3: seq=1 ttl=64 time=0.080 ms
64 bytes from 172.17.0.3: seq=2 ttl=64 time=0.074 ms
--- 172.17.0.3 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 0.074/0.083/0.096 ms
```
Finally, use the `cat` command to check the `container1` network configuration:
```
root@0cb243cd1293:/# cat /etc/hosts
172.17.0.2 3386a527aa08
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
```
To detach from a `container1` and leave it running use `CTRL-p CTRL-q`.Then, attach to `container2` and repeat these three commands.
```
$ docker attach container2
root@0cb243cd1293:/# ifconfig
eth0 Link encap:Ethernet HWaddr 02:42:AC:11:00:03
inet addr:172.17.0.3 Bcast:0.0.0.0 Mask:255.255.0.0
inet6 addr: fe80::42:acff:fe11:3/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:9001 Metric:1
RX packets:15 errors:0 dropped:0 overruns:0 frame:0
TX packets:13 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:1166 (1.1 KiB) TX bytes:1026 (1.0 KiB)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
root@0cb243cd1293:/# ping -w3 172.17.0.2
PING 172.17.0.2 (172.17.0.2): 56 data bytes
64 bytes from 172.17.0.2: seq=0 ttl=64 time=0.067 ms
64 bytes from 172.17.0.2: seq=1 ttl=64 time=0.075 ms
64 bytes from 172.17.0.2: seq=2 ttl=64 time=0.072 ms
--- 172.17.0.2 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 0.067/0.071/0.075 ms
/ # cat /etc/hosts
172.17.0.3 94447ca47985
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
```
The default `docker0` bridge network supports the use of port mapping and `docker run --link` to allow communications between containers in the `docker0` network. These techniques are cumbersome to set up and prone to error. While they are still available to you as techniques, it is better to avoid them and define your own bridge networks instead.
## User-defined networks
You can create your own user-defined networks that better isolate containers.
Docker provides some default **network drivers** for creating these networks.
You can create a new **bridge network**, **overlay network** or **MACVLAN
network**. You can also create a **network plugin** or **remote network**
written to your own specifications.
You can create multiple networks. You can add containers to more than one
network. Containers can only communicate within networks but not across
networks. A container attached to two networks can communicate with member
containers in either network. When a container is connected to multiple
networks, its external connectivity is provided via the first non-internal
network, in lexical order.
The next few sections describe each of Docker's built-in network drivers in
greater detail.
### A bridge network
The easiest user-defined network to create is a `bridge` network. This network
is similar to the historical, default `docker0` network. There are some added
features and some old features that aren't available.
```
$ docker network create --driver bridge isolated_nw
1196a4c5af43a21ae38ef34515b6af19236a3fc48122cf585e3f3054d509679b
$ docker network inspect isolated_nw
[
{
"Name": "isolated_nw",
"Id": "1196a4c5af43a21ae38ef34515b6af19236a3fc48122cf585e3f3054d509679b",
"Scope": "local",
"Driver": "bridge",
"IPAM": {
"Driver": "default",
"Config": [
{
"Subnet": "172.21.0.0/16",
"Gateway": "172.21.0.1/16"
}
]
},
"Containers": {},
"Options": {}
}
]
$ docker network ls
NETWORK ID NAME DRIVER
9f904ee27bf5 none null
cf03ee007fb4 host host
7fca4eb8c647 bridge bridge
c5ee82f76de3 isolated_nw bridge
```
After you create the network, you can launch containers on it using the `docker run --network=<NETWORK>` option.
```
$ docker run --network=isolated_nw -itd --name=container3 busybox
8c1a0a5be480921d669a073393ade66a3fc49933f08bcc5515b37b8144f6d47c
$ docker network inspect isolated_nw
[
{
"Name": "isolated_nw",
"Id": "1196a4c5af43a21ae38ef34515b6af19236a3fc48122cf585e3f3054d509679b",
"Scope": "local",
"Driver": "bridge",
"IPAM": {
"Driver": "default",
"Config": [
{}
]
},
"Containers": {
"8c1a0a5be480921d669a073393ade66a3fc49933f08bcc5515b37b8144f6d47c": {
"EndpointID": "93b2db4a9b9a997beb912d28bcfc117f7b0eb924ff91d48cfa251d473e6a9b08",
"MacAddress": "02:42:ac:15:00:02",
"IPv4Address": "172.21.0.2/16",
"IPv6Address": ""
}
},
"Options": {}
}
]
```
The containers you launch into this network must reside on the same Docker host.
Each container in the network can immediately communicate with other containers
in the network. Though, the network itself isolates the containers from external
networks.
![An isolated network](images/bridge_network.png)
Within a user-defined bridge network, linking is not supported. You can
expose and publish container ports on containers in this network. This is useful
if you want to make a portion of the `bridge` network available to an outside
network.
![Bridge network](images/network_access.png)
A bridge network is useful in cases where you want to run a relatively small
network on a single host. You can, however, create significantly larger networks
by creating an `overlay` network.
### An overlay network with Docker Engine swarm mode
You can create an overlay network on a manager node running in swarm mode
without an external key-value store. The swarm makes the overlay network
available only to nodes in the swarm that require it for a service. When you
create a service that uses the overlay network, the manager node automatically
extends the overlay network to nodes that run service tasks.
To learn more about running Docker Engine in swarm mode, refer to the
[Swarm mode overview](../../swarm/index.md).
The example below shows how to create a network and use it for a service from a manager node in the swarm:
```bash
# Create an overlay network `my-multi-host-network`.
$ docker network create \
--driver overlay \
--subnet 10.0.9.0/24 \
my-multi-host-network
400g6bwzd68jizzdx5pgyoe95
# Create an nginx service and extend the my-multi-host-network to nodes where
# the service's tasks run.
$ $ docker service create --replicas 2 --network my-multi-host-network --name my-web nginx
716thylsndqma81j6kkkb5aus
```
Overlay networks for a swarm are not available to containers started with
`docker run` that don't run as part of a swarm mode service. For more
information refer to [Docker swarm mode overlay network security model](overlay-security-model.md).
### An overlay network with an external key-value store
If you are not using Docker Engine in swarm mode, the `overlay` network requires
a valid key-value store service. Supported key-value stores include Consul,
Etcd, and ZooKeeper (Distributed store). Before creating a network on this
version of the Engine, you must install and configure your chosen key-value
store service. The Docker hosts that you intend to network and the service must
be able to communicate.
>**Note:** Docker Engine running in swarm mode is not compatible with networking
with an external key-value store.
![Key-value store](images/key_value.png)
Each host in the network must run a Docker Engine instance. The easiest way to
provision the hosts is with Docker Machine.
![Engine on each host](images/engine_on_net.png)
You should open the following ports between each of your hosts.
| Protocol | Port | Description |
|----------|------|-----------------------|
| udp | 4789 | Data plane (VXLAN) |
| tcp/udp | 7946 | Control plane |
Your key-value store service may require additional ports.
Check your vendor's documentation and open any required ports.
Once you have several machines provisioned, you can use Docker Swarm to quickly
form them into a swarm which includes a discovery service as well.
To create an overlay network, you configure options on the `daemon` on each
Docker Engine for use with `overlay` network. There are three options to set:
<table>
<thead>
<tr>
<th>Option</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td><pre>--cluster-store=PROVIDER://URL</pre></td>
<td>Describes the location of the KV service.</td>
</tr>
<tr>
<td><pre>--cluster-advertise=HOST_IP|HOST_IFACE:PORT</pre></td>
<td>The IP address or interface of the HOST used for clustering.</td>
</tr>
<tr>
<td><pre>--cluster-store-opt=KEY-VALUE OPTIONS</pre></td>
<td>Options such as TLS certificate or tuning discovery Timers</td>
</tr>
</tbody>
</table>
Create an `overlay` network on one of the machines in the Swarm.
$ docker network create --driver overlay my-multi-host-network
This results in a single network spanning multiple hosts. An `overlay` network
provides complete isolation for the containers.
![An overlay network](images/overlay_network.png)
Then, on each host, launch containers making sure to specify the network name.
$ docker run -itd --network=my-multi-host-network busybox
Once connected, each container has access to all the containers in the network
regardless of which Docker host the container was launched on.
![Published port](images/overlay-network-final.png)
If you would like to try this for yourself, see the [Getting started for
overlay](get-started-overlay.md).
### Custom network plugin
If you like, you can write your own network driver plugin. A network
driver plugin makes use of Docker's plugin infrastructure. In this
infrastructure, a plugin is a process running on the same Docker host as the
Docker `daemon`.
Network plugins follow the same restrictions and installation rules as other
plugins. All plugins make use of the plugin API. They have a lifecycle that
encompasses installation, starting, stopping and activation.
Once you have created and installed a custom network driver, you use it like the
built-in network drivers. For example:
$ docker network create --driver weave mynet
You can inspect it, add containers to and from it, and so forth. Of course,
different plugins may make use of different technologies or frameworks. Custom
networks can include features not present in Docker's default networks. For more
information on writing plugins, see [Extending Docker](../../extend/index.md) and
[Writing a network driver plugin](../../extend/plugins_network.md).
### Docker embedded DNS server
Docker daemon runs an embedded DNS server to provide automatic service discovery
for containers connected to user defined networks. Name resolution requests from
the containers are handled first by the embedded DNS server. If the embedded DNS
server is unable to resolve the request it will be forwarded to any external DNS
servers configured for the container. To facilitate this when the container is
created, only the embedded DNS server reachable at `127.0.0.11` will be listed
in the container's `resolv.conf` file. More information on embedded DNS server on
user-defined networks can be found in the [embedded DNS server in user-defined networks]
(configure-dns.md)
## Links
Before the Docker network feature, you could use the Docker link feature to
allow containers to discover each other. With the introduction of Docker networks,
containers can be discovered by its name automatically. But you can still create
links but they behave differently when used in the default `docker0` bridge network
compared to user-defined networks. For more information, please refer to
[Legacy Links](default_network/dockerlinks.md) for link feature in default `bridge` network
and the [linking containers in user-defined networks](work-with-networks.md#linking-containers-in-user-defined-networks) for links
functionality in user-defined networks.
## Related information
- [Understand Docker container networks](dockernetworks.md)
- [Work with network commands](work-with-networks.md)
- [Get started with multi-host networking](get-started-overlay.md)
If you are already familiar with Docker's default bridge network, `docker0` that network continues to be supported. It is created automatically in every installation. The default bridge network is also named `bridge`. To see a list of topics related to that network, read the articles listed in the [Docker default bridge network](default_network/index.md).
- [Managing Data in Containers](../../tutorials/dockervolumes.md)
- [Docker Machine overview](https://docs.docker.com/machine)
- [Docker Swarm overview](https://docs.docker.com/swarm)
- [Investigate the LibNetwork project](https://github.com/docker/libnetwork)

22
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@ -0,0 +1,22 @@
<!--[metadata]>
+++
title = "Network configuration"
description = "Docker networking feature is introduced"
keywords = ["network, networking, bridge, docker, documentation"]
type="menu"
[menu.main]
identifier="smn_networking"
parent= "engine_guide"
weight=7
+++
<![end-metadata]-->
# Docker networks feature overview
This sections explains how to use the Docker networks feature. This feature allows users to define their own networks and connect containers to them. Using this feature you can create a network on a single host or a network that spans across multiple hosts.
- [Understand Docker container networks](index.md)
- [Work with network commands](work-with-networks.md)
- [Get started with multi-host networking](get-started-overlay.md)
If you are already familiar with Docker's default bridge network, `docker0` that network continues to be supported. It is created automatically in every installation. The default bridge network is also named `bridge`. To see a list of topics related to that network, read the articles listed in the [Docker default bridge network](default_network/index.md).

66
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@ -0,0 +1,66 @@
<!--[metadata]>
+++
title = "Swarm mode overlay network security model"
description = "Docker swarm mode overlay network security model"
keywords = ["network, docker, documentation, user guide, multihost, swarm mode", "overlay"]
[menu.main]
parent = "smn_networking"
weight=-2
+++
<![end-metadata]-->
# Docker swarm mode overlay network security model
Overlay networking for Docker Engine swarm mode comes secure out of the box. The
swarm nodes exchange overlay network information using a gossip protocol. By
default the nodes encrypt and authenticate information they exchange via gossip
using the [AES algorithm](https://en.wikipedia.org/wiki/Galois/Counter_Mode) in
GCM mode. Manager nodes in the swarm rotate the key used to encrypt gossip data
every 12 hours.
You can also encrypt data exchanged between containers on different nodes on the
overlay network. To enable encryption, when you create an overlay network pass
the `--opt encrypted` flag:
```bash
$ docker network create --opt encrypted --driver overlay my-multi-host-network
dt0zvqn0saezzinc8a5g4worx
```
When you enable overlay encryption, Docker creates IPSEC tunnels between all the
nodes where tasks are scheduled for services attached to the overlay network.
These tunnels also use the AES algorithm in GCM mode and manager nodes
automatically rotate the keys every 12 hours.
## Swarm mode overlay networks and unmanaged containers
Because the overlay networks for swarm mode use encryption keys from the manager
nodes to encrypt the gossip communications, only containers running as tasks in
the swarm have access to the keys. Consequently, containers started outside of
swarm mode using `docker run` (unmanaged containers) cannot attach to the
overlay network.
For example:
```bash
$ docker run --network my-multi-host-network nginx
docker: Error response from daemon: swarm-scoped network
(my-multi-host-network) is not compatible with `docker create` or `docker
run`. This network can only be used by a docker service.
```
To work around this situation, migrate the unmanaged containers to managed
services. For instance:
```bash
$ docker service create --network my-multi-host-network my-image
```
Because [swarm mode](../../swarm/index.md) is an optional feature, the Docker
Engine preserves backward compatibility. You can continue to rely on a
third-party key-value store to support overlay networking if you wish.
However, switching to swarm-mode is strongly encouraged. In addition to the
security benefits described in this article, swarm mode enables you to leverage
the substantially greater scalability provided by the new services API.

2
docs/userguide/networking/work-with-networks.md
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@ -23,7 +23,7 @@ available through the Docker Engine CLI. These commands are:
* `docker network inspect`
While not required, it is a good idea to read [Understanding Docker
network](dockernetworks.md) before trying the examples in this section. The
network](index.md) before trying the examples in this section. The
examples for the rely on a `bridge` network so that you can try them
immediately. If you would prefer to experiment with an `overlay` network see
the [Getting started with multi-host networks](get-started-overlay.md) instead.