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Update get-started-overlay.md (#4189)

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Wang Jie
2017-08-18 05:36:59 +08:00
committed by Misty Stanley-Jones
parent 83eeff7182
commit 0ea61642e8
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engine/userguide/networking/get-started-overlay.md
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@@ -5,11 +5,11 @@ title: Get started with multi-host networking
---
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
network. Docker 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:
* [Docker Engine running in swarm mode](#overlay-networking-and-swarm-mode)
* [Docker running in swarm mode](#overlay-networking-and-swarm-mode)
OR
@@ -17,14 +17,14 @@ OR
## 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.
Using Docker 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
To learn more about running Docker 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:
@@ -51,7 +51,7 @@ See also [Attach services to an overlay network](../../swarm/networking.md).
## Overlay networking with an external key-value store
To use an Docker engine with an external key-value store, you need the
To use a Docker engine with an external key-value store, you need the
following:
* Access to the key-value store. Docker supports Consul, Etcd, and ZooKeeper
@@ -124,7 +124,7 @@ key-value stores. This example uses Consul.
Keep your terminal open and move onto the next step.
### 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
@@ -132,7 +132,7 @@ machines in VirtualBox. One of the machines will act as the swarm master;
you'll create that first. As you create each host, you'll pass the Engine on
that machine options that are needed by the `overlay` network driver.
1. Create a swarm master.
1. Create a swarm master.
$ docker-machine create \
-d virtualbox \
@@ -144,7 +144,7 @@ that machine options that are needed by the `overlay` network driver.
At creation time, you supply the Engine `daemon` with the `--cluster-store` option. This option tells the Engine the location of the key-value store for the `overlay` network. The bash expansion `$(docker-machine ip mh-keystore)` resolves to the IP address of the Consul server you created in "STEP 1". The `--cluster-advertise` option advertises the machine on the network.
2. Create another host and add it to the swarm cluster.
2. Create another host and add it to the swarm cluster.
$ docker-machine create -d virtualbox \
--swarm \
@@ -153,7 +153,7 @@ that machine options that are needed by the `overlay` network driver.
--engine-opt="cluster-advertise=eth1:2376" \
mhs-demo1
3. List your machines to confirm they are all up and running.
3. List your machines to confirm they are all up and running.
$ docker-machine ls
@@ -171,13 +171,13 @@ Leave your terminal open and go onto the next step.
To create an overlay network
1. Set your docker environment to the swarm master.
1. Set your docker environment to the swarm master.
$ eval $(docker-machine env --swarm mhs-demo0)
Using the `--swarm` flag with `docker-machine` restricts the `docker` commands to swarm information alone.
2. Use the `docker info` command to view the swarm.
Using the `--swarm` flag with `docker-machine` restricts the `docker` commands to swarm information alone.
2. Use the `docker info` command to view the swarm.
$ docker info
@@ -203,19 +203,20 @@ To create an overlay network
From this information, you can see that you are running three containers and two images on the Master.
3. Create your `overlay` network.
3. Create your `overlay` network.
$ docker network create --driver overlay --subnet=10.0.9.0/24 my-net
You only need to create the network on a single host in the cluster. In this case, you used the swarm master but you could easily have run it on any host in the cluster.
You only need to create the network on a single host in the cluster. In this case,
you used the swarm master but you could easily have run it on any host in the cluster.
> **Note** : It is highly recommended to use the `--subnet` option when creating
> a network. If the `--subnet` is not specified, the docker daemon automatically
> chooses and assigns a subnet for the network and it could overlap with another subnet
> in your infrastructure that is not managed by docker. Such overlaps can cause
> connectivity issues or failures when containers are connected to that network.
> **Note**: It is highly recommended to use the `--subnet` option when creating
> a network. If the `--subnet` is not specified, the docker daemon automatically
> chooses and assigns a subnet for the network and it could overlap with another subnet
> in your infrastructure that is not managed by docker. Such overlaps can cause
> connectivity issues or failures when containers are connected to that network.
4. Check that the network is running:
4. Check that the network is running:
$ docker network ls
@@ -228,11 +229,11 @@ To create an overlay network
d0bb78cbe7bd mhs-demo1/bridge bridge
1c0eb8f69ebb mhs-demo1/none null
As you are in the swarm master environment, you see all the networks on all
the swarm agents: the default networks on each engine and the single overlay
network. Notice that each `NETWORK ID` is unique.
As you are in the swarm master environment, you see all the networks on all
the swarm agents: the default networks on each engine and the single overlay
network. Notice that each `NETWORK ID` is unique.
5. Switch to each swarm agent in turn and list the networks.
5. Switch to each swarm agent in turn and list the networks.
$ eval $(docker-machine env mhs-demo0)
@@ -254,22 +255,22 @@ To create an overlay network
412c2496d0eb host host
6b07d0be843f my-net overlay
Both agents report they have the `my-net` network with the `6b07d0be843f` ID.
You now have a multi-host container network running!
Both agents report they have the `my-net` network with the `6b07d0be843f` ID.
You now have a multi-host container network running!
### 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.
1. Point your environment to the swarm master.
1. Point your environment to the swarm master.
$ eval $(docker-machine env --swarm mhs-demo0)
2. Start an Nginx web server on the `mhs-demo0` instance.
2. Start an Nginx web server on the `mhs-demo0` instance.
$ docker run -itd --name=web --network=my-net --env="constraint:node==mhs-demo0" nginx
4. Run a BusyBox instance on the `mhs-demo1` instance and get the contents of the Nginx server's home page.
4. Run a BusyBox instance on the `mhs-demo1` instance and get the contents of the Nginx server's home page.
$ docker run -it --rm --network=my-net --env="constraint:node==mhs-demo1" busybox wget -O- http://web
@@ -315,11 +316,11 @@ Additionally, containers connected to the multi-host network are automatically
connected to the `docker_gwbridge` network. This network allows the containers
to have external connectivity outside of their cluster.
1. Change your environment to the swarm agent.
1. Change your environment to the swarm agent.
$ eval $(docker-machine env mhs-demo1)
2. View the `docker_gwbridge` network, by listing the networks.
2. View the `docker_gwbridge` network, by listing the networks.
$ docker network ls
@@ -330,7 +331,7 @@ to have external connectivity outside of their cluster.
1aeead6dd890 host host
e1dbd5dff8be docker_gwbridge bridge
3. Repeat steps 1 and 2 on the swarm master.
3. Repeat steps 1 and 2 on the swarm master.
$ eval $(docker-machine env mhs-demo0)
@@ -343,7 +344,7 @@ to have external connectivity outside of their cluster.
412c2496d0eb host host
97102a22e8d2 docker_gwbridge bridge
2. Check the Nginx container's network interfaces.
2. Check the Nginx container's network interfaces.
$ docker exec web ip addr
@@ -370,7 +371,7 @@ 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.
### Extra Credit with Docker Compose
### Extra credit with Docker Compose
Please refer to the Networking feature introduced in
[Compose V2 format](/compose/networking/)