Docs for CNI plugins

site/features.md

@@ -10,6 +10,7 @@ Net:
  * [Fast Data Path](#fast-data-path)
  * [Seamless Docker Integration](#docker)
  * [Docker Network Plugin](#plugin)
+ * [CNI Plugin](#cniplugin)
  * [Address Allocation (IPAM)](#addressing)
  * [Naming and Discovery](#naming-and-discovery)
  * [Application Isolation](#application-isolation)
@@ -100,6 +101,13 @@ when there are network connectivity problems.
 See [Using the Weave Docker Network Plugin](/site/plugin/weave-plugin-how-to.md) for more details.
 
 
+###<a name="cniplugin"></a>Weave Network CNI Plugin
+
+Weave can be used as a plugin to systems that support the [Container Network Interface](https://github.com/appc/cni), such as Kubernetes.
+
+See [Using the Weave CNI Plugin](/site/plugin/cni-plugin-how-to.md) for more details.
+
+
 ###<a name="addressing"></a>IP Address Management (IPAM)
  
 Containers are automatically allocated a unique IP address. To view the addresses allocated by Weave run, `weave ps`.

site/plugin/cni-plugin-how-to.md

@@ -0,0 +1,77 @@
+---
+title: Using the Weave Net CNI Plugin
+layout: default
+---
+
+CNI, the [_Container Network Interface_](https://github.com/appc/cni#cni---the-container-network-interface),
+is a proposed standard for configuring network interfaces for Linux
+application containers.  CNI is supported by
+[Kubernetes](http://kubernetes.io/), an open source container cluster
+manager built by Google.
+
+###Installing the Weave Net CNI plugin
+
+The Weave Net CNI plugin is installed when you run `weave setup`, if
+it your machine has the directories normally used to host CNI plugins.
+To create those directories, run (as root):
+
+    mkdir -p /opt/cni/bin
+    mkdir -p /etc/cni/net.d
+
+Then run:
+
+    weave setup
+
+###Launching Weave Net
+
+To create a network which can span multiple hosts, the Weave peers must be connected to each other, by specifying the other hosts during `weave launch` or via
+[`weave connect`](/site/using-weave/finding-adding-hosts-dynamically.md).
+
+See [Deploying Applications to Weave Net](/site/using-weave/deploying-applications.md#peer-connections) for a discussion on peer connections. 
+
+As well as launching Weave Net, you have to run an extra command to
+configure the Weave bridge:
+
+    weave launch <peer hosts>
+    weave expose
+
+###Configuring Kubernetes to use the CNI Plugin
+
+After you've launched Weave and peered your hosts, you can configure
+Kubernetes to use Weave, by adding the following options to the
+`kubelet` command:
+
+    --network-plugin=cni --network-plugin-dir=/etc/cni/net.d
+
+See the [`kubelet` documentation](http://kubernetes.io/v1.1/docs/admin/kubelet.html)
+for more details.
+
+Now, whenever Kubernetes starts a pod, it will be attached to the Weave network.
+
+###The CNI network configuration file
+
+All CNI plugins are configured by a JSON file in the directory
+`/etc/cni/net.d/`.  `weave setup` installs a minimal configuration
+file named `10-weave.conf`, which you can alter to suit your needs.
+
+See the [CNI Spec]](https://github.com/appc/cni/blob/master/SPEC.md#network-configuration)
+for details on the format and contents of this file.
+
+By default, the Weave CNI plugin will add a default route out via the Weave bridge, so your containers can access resources on the internet.  If you do not want this, add a section to the config file specifying no routes:
+
+```
+    "ipam": {
+        "routes": [ ]
+    }
+```
+
+The following other fields in the spec are supported:
+
+- `ipam / type` - default is to use Weave's own IPAM
+- `ipam / subnet` - default is to use Weave's IPAM default subnet
+- `ipam / gateway` - default is to use the Weave bridge IP address (allocated by `weave expose`)
+
+###Caveats
+
+- The Weave router container must be running for CNI to allocate addresses
+- The CNI plugin does not add entries to Weave DNS.