[Addon kubevela#603] Add Apache Spark as a experimental addon

Signed-off-by: yanghua <[email protected]>

Author: yanghua

experimental/addons/spark-kubernetes-operator/README.md

@@ -160,4 +160,11 @@ metadata:
 ......
 ```
 
+4. Show the service of spark application via this command:
 
+```
+$ kubectl get svc -n spark-cluster
+NAME                                       TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)                      AGE
+my-spark-app-c58a1c869214bfe5-driver-svc   ClusterIP   None             <none>        7078/TCP,7079/TCP,4040/TCP   19m
+my-spark-app-ui-svc                        ClusterIP   xx.xx.xx.xx   <none>        4040/TCP                     19m
+```