Add documentation

Author: tnachen

docs/running-on-mesos.md

@@ -78,6 +78,9 @@ To verify that the Mesos cluster is ready for Spark, navigate to the Mesos maste
 To use Mesos from Spark, you need a Spark binary package available in a place accessible by Mesos, and
 a Spark driver program configured to connect to Mesos.
 
+Alternatively, you can also install Spark in the same location in all the Mesos slaves, and configure
+`spark.mesos.executor.home` (defaults to SPARK_HOME) to point to that location.
+
 ## Uploading Spark Package
 
 When Mesos runs a task on a Mesos slave for the first time, that slave must have a Spark binary
@@ -107,7 +110,11 @@ the `make-distribution.sh` script included in a Spark source tarball/checkout.
 The Master URLs for Mesos are in the form `mesos://host:5050` for a single-master Mesos
 cluster, or `mesos://zk://host:2181` for a multi-master Mesos cluster using ZooKeeper.
 
-The driver also needs some configuration in `spark-env.sh` to interact properly with Mesos:
+## Client Mode
+
+In client mode, a Spark Mesos framework is launched directly on the client machine and waits for the driver output.
+
+The driver needs some configuration in `spark-env.sh` to interact properly with Mesos:
 
 1. In `spark-env.sh` set some environment variables:
  * `export MESOS_NATIVE_JAVA_LIBRARY=<path to libmesos.so>`. This path is typically
@@ -129,8 +136,7 @@ val sc = new SparkContext(conf)
 {% endhighlight %}
 
 (You can also use [`spark-submit`](submitting-applications.html) and configure `spark.executor.uri`
-in the [conf/spark-defaults.conf](configuration.html#loading-default-configurations) file. Note
-that `spark-submit` currently only supports deploying the Spark driver in `client` mode for Mesos.)
+in the [conf/spark-defaults.conf](configuration.html#loading-default-configurations) file.)
 
 When running a shell, the `spark.executor.uri` parameter is inherited from `SPARK_EXECUTOR_URI`, so
 it does not need to be redundantly passed in as a system property.
@@ -139,6 +145,17 @@ it does not need to be redundantly passed in as a system property.
 ./bin/spark-shell --master mesos://host:5050
 {% endhighlight %}
 
+## Cluster mode
+
+Spark on Mesos also supports cluster mode, where the driver is launched in the cluster and the client
+can find the results of the driver from the Mesos Web UI.
+
+To use cluster mode, you must start the MesosClusterDispatcher in your cluster via the `sbin/start-mesos-dispatcher.sh` script,
+passing in the Mesos master url (ie: mesos://host:5050).
+
+From the client, you can submit a job to Mesos cluster by running `spark-submit` and specifying the master url
+to the url of the MesosClusterDispatcher (ie: mesos://dispatcher:7077). You can view driver statuses on the
+Spark cluster Web UI.
 
 # Mesos Run Modes