Add public MEC enabled doc

docs/book/src/topics/publicmec-enabled-clusters.md

@@ -0,0 +1,79 @@
+# Public MEC enabled clusters
+
+- **Feature status:** Experimental
+- **Feature gate:** EdgeZone=true
+
+## Overview
+
+Cluster API Provider Azure (CAPZ) experimentally supports public MEC enabled Kubernetes clusters on Microsoft Azure.
+Before you begin, be aware that:
+
+- [Azure Public MEC](https://azure.microsoft.com/en-us/solutions/public-multi-access-edge-compute-mec) introduction
+- Public MEC is now only open to limited users in specific subscription
+
+To deploy a cluster on public MEC, use the [edgezone flavor](https://raw.githubusercontent.com/kubernetes-sigs/cluster-api-provider-azure/main/templates/cluster-template-edgezone.yaml).
+
+## Example: Deploy a public MEC enabled cluster by `clusterctl`
+
+A clusterctl flavor exists to deploy an public MEC enabled cluster with CAPZ. This flavor requires the following environment variables to be set before executing clusterctl.
+
+```bash
+# Kubernetes values
+export CLUSTER_NAME="my-cluster"
+export WORKER_MACHINE_COUNT=2
+export CONTROL_PLANE_MACHINE_COUNT=1
+export KUBERNETES_VERSION="v1.25.0"
+
+# Azure values
+export AZURE_LOCATION="eastus2euap"
+export AZURE_EXTENDEDLOCATION_TYPE="EdgeZone"
+export AZURE_EXTENDEDLOCATION_NAME="microsoftrrdclab3"
+export AZURE_RESOURCE_GROUP="${CLUSTER_NAME}"
+```
+
+Create a new service principal and save to local file:
+```bash
+az ad sp create-for-rbac --role Contributor --scopes="/subscriptions/${AZURE_SUBSCRIPTION_ID}" --sdk-auth > sp.json
+```
+export the following variables in you current shell.
+```bash
+export AZURE_SUBSCRIPTION_ID="$(cat sp.json | jq -r .subscriptionId | tr -d '\n')"
+export AZURE_CLIENT_SECRET="$(cat sp.json | jq -r .clientSecret | tr -d '\n')"
+export AZURE_CLIENT_ID="$(cat sp.json | jq -r .clientId | tr -d '\n')"
+export AZURE_CONTROL_PLANE_MACHINE_TYPE="Standard_D2s_v3"
+export AZURE_NODE_MACHINE_TYPE="Standard_D2s_v3"
+export AZURE_CLUSTER_IDENTITY_SECRET_NAME="cluster-identity-secret"
+export AZURE_CLUSTER_IDENTITY_SECRET_NAMESPACE="default"
+export CLUSTER_IDENTITY_NAME="cluster-identity"
+```
+
+Public MEC enabled clusters also require the following feature flags set as environment variables:
+
+```bash
+export EXP_EDGEZONE=true
+```
+
+Create a local kind cluster to run the managemenet cluster components:
+
+```bash
+kind create cluster
+```
+
+Create an identity secret on the management cluster:
+
+```bash
+kubectl create secret generic "${AZURE_CLUSTER_IDENTITY_SECRET_NAME}" --from-literal=clientSecret="${AZURE_CLIENT_SECRET}"
+```
+
+Execute clusterctl to template the resources, then apply to your kind management cluster.
+
+```bash
+clusterctl init --infrastructure azure
+clusterctl generate cluster ${CLUSTER_NAME} --kubernetes-version ${KUBERNETES_VERSION} --flavor edgezone > edgezone-cluster.yaml
+
+# assumes an existing management cluster
+kubectl apply -f edgezone-cluster.yaml
+```
+
+
+