Initial awsvpc docs

site/installing-weave.md

@@ -32,6 +32,8 @@ With Weave Net downloaded onto your VMs or hosts, you are ready to launch a Weav
 
 CoreOS users see [here](/guides/networking-docker-containers-with-weave-on-coreos/) for an example of installing Weave using cloud-config.
 
+Amazon AWS users may want to use AWSVPC?
+
 Amazon ECS users see [here](https://github.com/weaveworks/integrations/blob/master/aws/ecs/README.md)
 for the latest Weave AMIs and [here](http://weave.works/guides/service-discovery-with-weave-aws-ecs.html) to get started with Weave Net on ECS.
 

site/using-weave/awsvpc.md

@@ -0,0 +1,91 @@
+---
+title: Using IP Routing on an Amazon Web Services Virtual Private Cloud
+menu_order: 110
+---
+
+If you are running your container infrastructure entirely within
+Amazon Web Services (AWS) EC2 (Elastic Compute Cloud), then you can
+choose AWS-VPC mode to connect your containers without any overlay, so
+they can operate very close to the full speed of the underlying
+network.
+
+In this mode, Weave Net still manages IP addresses and connects
+containers to the network, but instead of wrapping up each packet and
+sending it to its destination, Weave Net instructs the AWS network
+router which ranges of container IP addresses live on which instance.
+
+###Configuring your EC2 instances to use Weave AWS-VPC mode
+
+First, your AWS instances need to be given access to change the route
+table.  Give them an IAM Role which has this access; if you have an
+existing role then extend it or create a new one with a policy
+allowing the necessary actions:
+
+```
+{
+    "Version": "2012-10-17",
+    "Statement": [
+        {
+            "Effect": "Allow",
+            "Action": [
+                "ec2:CreateRoute",
+                "ec2:DeleteRoute",
+                "ec2:ReplaceRoute",
+                "ec2:DescribeRouteTables",
+                "ec2:DescribeInstances"
+            ],
+            "Resource": [
+                "*"
+            ]
+        }
+    ]
+}
+```
+
+Your Security Group must allow network traffic between instances: you
+must open TCP port 6783 which Weave Net uses to manage the network,
+and you must allow any ports which your own containers use. Remember:
+there is no network overlay in this mode so IP packets with container
+addresses will flow over the AWS network unmodified.
+
+Also, you must disable the "Source/Destination check" on each machine,
+because Weave will be operating with IP addresses outside of the range
+allocated by Amazon.
+
+###Using AWS-VPC mode
+
+Launch Weave Net, adding the `--awsvpc` flag:
+
+    $ weave launch --awsvpc [other hosts]
+
+You still need to supply the names or IP addresses of other hosts in
+your cluster.
+
+###Limitations
+
+- AWS-VPC mode does not inter-operate with other Weave Net modes; it
+  is all or nothing.  In this mode, all hosts in a cluster must be AWS
+  instances. We hope to ease this limitation in future.
+- The AWS network does not support multicast.
+- The number of hosts in a cluster is limited by the maximum size of
+  your AWS route table.  This is are limited to 50 entries though you
+  can request an increase to 100.
+- All your containers must be on the same network, with no subnet
+  isolation. We hope to ease this limitation in future.
+
+###Packet size (MTU)
+
+The Maximum Transmission Unit, or MTU, is the technical term for the
+limit on how big a single packet can be on the network. Weave Net
+defaults to 1410 bytes which works across almost all networks, but you
+can set a larger size for better performance.
+
+The AWS network supports packets of 9000 bytes, so in AWS-VPC mode you
+can run:
+
+    $ WEAVE_MTU=9000 weave launch --awsvpc host2 host3
+
+**See Also**
+
+ * [Using Weave Net](/site/using-weave.md)
+ * [Performance measurements](/blog/weave-docker-networking-performance-aws-vpc/)