2020-10-14 ML: add details for deployment, service, ingress and ingressDNSRecord

README.md

@@ -359,6 +359,8 @@ The main configuration are:
 - **domain-filter**: will make ExternalDNS see only the zones matching provided domain;
 - **policy**: are the permissions with which External DNS can operate on PowerDNS.
 
+For more details see: https://github.com/kubernetes-sigs/external-dns/blob/master/docs/tutorials/pdns.md.
+
 ### Federate deployment
 
 Now create the federated deployment (for this example we used a simple "Hello World" image):
@@ -404,6 +406,8 @@ spec:
 $ kubectl --context=<host-cluster-context> create -f resource/federated_deployment.yaml
 ```
 
+In this way the deployment resource will create inside the member clusters and it will create the pods for your application or image. In the previous example we add the `overrides` field to increse the number of pods in the member-cluster-2.
+
 ### Federate service
 
 Create the service for the "fed-helloworld" deployment:
@@ -441,9 +445,11 @@ spec:
 $ kubectl --context=<host-cluster-context> create -f resource/federated_service.yaml
 ```
 
+This is a ClusterIP service, in this way the your application is not exposed and the service have a private cluster IP. Now it is necessary that the service is exposed by an ingress resource.
+
 ### Federate ingress
 
-Now it is possible create the ingress resource for the fed-helloworld-service:
+Create the ingress resource to expose the fed-helloworld-service:
 
 ```yaml
 # federated_ingress.yaml
@@ -478,6 +484,8 @@ spec:
 $ kubectl --context=<host-cluster-context> create -f resource/federated_ingress.yaml
 ```
 
+In the "host" field the "<domain>" string must be the same that you insert in the "domain-filter" field for ExternalDNS configuration.
+
 ### List federated resources
 
 If you want to show or describe the federated resource that have been propagated on the Member Cluster, you can run the follow command:
@@ -510,3 +518,5 @@ spec:
 ```bash
 $ kubectl --context=<host-cluster-context> create -f resource/ingressdnsrecord.yaml
 ```
+
+The name of IngressDNSRecord must be the same of the ingress resource and the value in "hosts" field must matches the "host" field in the ingress configuration.
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