Clarify that only Calico supports K8s network policies (#2270)

docs/clusterdefinition.md

@@ -32,7 +32,7 @@ Here are the valid values for the orchestrator types:
 |---|---|---|
 |kubernetesImageBase|no|This specifies the base URL (everything preceding the actual image filename) of the kubernetes hyperkube image to use for cluster deployment, e.g., `k8s-gcrio.azureedge.net/`.|
 |dockerEngineVersion|no|Which version of docker-engine to use in your cluster, e.g.. "17.03.*"|
-|networkPolicy|no|Specifies the network policy tool for the cluster. Valid values are:<br>`"azure"` (default), which provides an Azure native networking experience,<br>`none` for not enforcing any network policy,<br>`calico` for Calico network policy (clusters with Linux agents only).<br>See [network policy examples](../examples/networkpolicy) for more information.|
+|networkPolicy|no|Specifies the network policy tool for the cluster. Valid values are:<br>`"azure"` (default), which provides an Azure native networking experience,<br>`none` for not enforcing any network policy,<br>`calico` for Calico network policy (required for Kubernetes network policies; clusters with Linux agents only).<br>See [network policy examples](../examples/networkpolicy) for more information.|
 |containerRuntime|no|The container runtime to use as a backend. The default is `docker`. The only other option is `clear-containers`.|
 |clusterSubnet|no|The IP subnet used for allocating IP addresses for pod network interfaces. The subnet must be in the VNET address space. Default value is 10.244.0.0/16.|
 |dnsServiceIP|no|IP address for kube-dns to listen on. If specified must be in the range of `serviceCidr`.|

examples/networkpolicy/README.md

@@ -6,6 +6,9 @@ There are 3 different Network Policy options :
 - Calico
 - Kubenet (none)
 
+Please note that only the `calico` network policy supports the Kubernetes notion
+of network policies.
+
 ## Azure Container Networking (default)
 
 By default (currently Linux clusters only), the `azure` network policy is applied. It is an open source implementation of [the CNI Network Plugin interface](https://github.com/containernetworking/cni/blob/master/SPEC.md) and [the CNI Ipam plugin interface](https://github.com/containernetworking/cni/blob/master/SPEC.md#ip-address-management-ipam-interface)
@@ -82,4 +85,4 @@ Also available is the Kubernetes-native kubenet implementation, which is declare
     }
     ...
   }
-```
+```