2020-10-12 ML: add namespace section

README.md

@@ -160,6 +160,7 @@ Command to show federated clusters:
 $ kubectl -n kube-federation-system get kubefedclusters
 ```
 
+
 ## Enable API
 
 To enable a type of resource to be federated it is necessary to use the enable command of kubefedctl:
@@ -189,3 +190,56 @@ $ kubefedctl disable services --kubefed-namespace kube-federation-system
 ```
 
 **N.B.**: Do not federate the “kind: pod” resource. In this case, federating a whole namespace will federate pods and deployments at the same time. Deployments will create replicasets which in turn create pods. It will result a duplication of the pods resources.
+
+
+## Deploy application
+
+Below the procedure to deploy and federate an application and enable ExternalDNS.
+
+### Create namespace (Host Cluster)
+
+The first step is create a namespace in the host cluster:
+
+command line:
+
+```bash
+$ kubectl create namespace <namespace-name>
+```
+
+or create it by yaml file (resource/namespace.yaml):
+
+```yaml
+# namespace.yaml file
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: fed-namespace
+```
+
+```bash
+$ kubectl create -f resource/namespace.yaml
+```
+
+### Federate namespace
+
+Once the namespace is created in the Host Cluster, it can be federate on the Member Cluster:
+
+```yaml
+# federated_namespace.yaml
+apiVersion: types.kubefed.io/v1beta1
+kind: FederatedNamespace
+metadata:
+  name: fed-namespace
+  namespace: fed-namespace
+spec:
+  placement:
+    clusters:
+    - name: member-cluster-1
+    - name: member-cluster-2
+```
+
+```bash
+$ kubectl --context=<host-cluster-context> create -f resource/federated_namespace.yaml
+```
+
+**N.B.**: the option `--context` is not necessary but make sure that the right context is selected.