Add instructions to find master URL (#169)

Author: foxish

docs/running-on-kubernetes.md

@@ -55,14 +55,23 @@ being contacted at `api_server_url`. If no HTTP protocol is specified in the URL
 setting the master to `k8s://example.com:443` is equivalent to setting it to `k8s://https://example.com:443`, but to
 connect without SSL on a different port, the master would be set to `k8s://http://example.com:8443`.
 
+
+If you have a Kubernetes cluster setup, one way to discover the apiserver URL is by executing `kubectl cluster-info`.
+
+    > kubectl cluster-info
+    Kubernetes master is running at http://127.0.0.1:8080
+
+In the above example, the specific Kubernetes cluster can be used with spark submit by specifying
+`--master k8s://http://127.0.0.1:8080` as an argument to spark-submit.
+
 Note that applications can currently only be executed in cluster mode, where the driver and its executors are running on
 the cluster.
 
 ### Dependency Management and Docker Containers
 
 Spark supports specifying JAR paths that are either on the submitting host's disk, or are located on the disk of the
 driver and executors. Refer to the [application submission](submitting-applications.html#advanced-dependency-management)
-section for details. Note that files specified with the `local` scheme should be added to the container image of both
+section for details. Note that files specified with the `local://` scheme should be added to the container image of both
 the driver and the executors. Files without a scheme or with the scheme `file://` are treated as being on the disk of
 the submitting machine, and are uploaded to the driver running in Kubernetes before launching the application.