Added discussion on viewing the Spark application UI.

spark/spark.ipynb

@@ -1,7 +1,7 @@
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+  "signature": "sha256:4117412dc3ddca1bb16e3800a74447569b7bd2b7484113922798e4326e254940"
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@@ -17,7 +17,8 @@
       "* Python Shell\n",
       "* RDDs\n",
       "* Pair RDDs\n",
-      "* Running Spark on a Cluster"
+      "* Running Spark on a Cluster\n",
+      "* Viewing the Spark Application UI"
      ]
     },
     {
@@ -464,6 +465,41 @@
      "language": "python",
      "metadata": {},
      "outputs": []
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "## Viewing the Spark Application UI"
+     ]
+    },
+    {
+     "cell_type": "markdown",
+     "metadata": {},
+     "source": [
+      "Every SparkContext launches a web UI, by default on port 4040, that displays useful information about the application. This includes:\n",
+      "\n",
+      "A list of scheduler stages and tasks\n",
+      "A summary of RDD sizes and memory usage\n",
+      "Environmental information.\n",
+      "Information about the running executors\n",
+      "\n",
+      "You can access this interface by simply opening http://<driver-node>:4040 in a web browser. If multiple SparkContexts are running on the same host, they will bind to successive ports beginning with 4040 (4041, 4042, etc).\n",
+      "\n",
+      "Note that this information is only available for the duration of the application by default. To view the web UI after the fact, set spark.eventLog.enabled to true before starting the application. This configures Spark to log Spark events that encode the information displayed in the UI to persisted storage.\n",
+      "\n",
+      "[Reference](http://spark.apache.org/docs/1.2.0/monitoring.html)"
+     ]
+    },
+    {
+     "cell_type": "code",
+     "collapsed": false,
+     "input": [
+      "http://localhost:4040/"
+     ],
+     "language": "python",
+     "metadata": {},
+     "outputs": []
     }
    ],
    "metadata": {}