Sample: on-premise-docker-registry

- Fix minor issue in Makefile target
- Update README.md

on-premise-docker-registry/Makefile

@@ -60,7 +60,7 @@ create-test-image:
 	docker push ${IMAGE_NAME}
 
 create-secret-to-pull-image:
-	kubectl create secret docker-registry on-premise-reg \
+	kubectl -n ${NAMESPACE} create secret docker-registry on-premise-reg \
       --docker-username=${REG_USER_NAME} \
       --docker-password=${REG_USER_PASSWD} \
       --docker-email=${EMAIL} \

on-premise-docker-registry/README.md

@@ -42,7 +42,7 @@ Export the following environment variables:
 ```shell
 export KUBECONFIG=<path-to-kubeconfig>
 export NAMESPACE={kyma-namespace-used-for-this-sample}
-export CLUSTER_DOMAIN={kyma-cluster-domain}
+export CLUSTER_DOMAIN=$(kubectl get cm -n kube-system shoot-info -ojsonpath='{.data.domain}')
 export REG_USER_NAME={docker-registry-user}
 export REG_USER_PASSWD={docker-registry-password}
 export EMAIL={your-email}
@@ -100,7 +100,7 @@ When creating a Deployment, specify the Docker registry as `localhost:{NodePort}
 
 This sample shows a simple configuration with Nginx as a reverse proxy. You can use any other reverse proxy implementation based on your on-premise Docker registry behavior and APIs.
 
-1. Create a Namespace and make sure Istio sidecar injection is enabled.
+1. Create a Namespace if not already created and make sure Istio sidecar injection is enabled.
 
    ```shell
    kubectl create namespace ${NAMESPACE}