Topology Summary section

This portion of the Storm UI shows the list of topologies running in the Storm cluster, along with their ID, the number of workers assigned to the topology, the number of executors, number of tasks, uptime, and so on.

Let's deploy the sample topology (if it is not running already) in a remote Storm cluster by running the following command:

$> cd $STORM_HOME
$> bin/storm jar ~/storm_example-0.0.1-SNAPSHOT-jar-with-dependencies.jar com.stormadvance.storm_example.SampleStormClusterTopology storm_example  

We have created the SampleStormClusterTopology topology by defining three worker processes, two executors for SampleSpout, and four executors for SampleBolt.

After submitting SampleStormClusterTopology on the Storm cluster, the user has to refresh the Storm home page.

The following screenshot shows that the row is added for SampleStormClusterTopology in the Topology Summary section. The topology section contains the name of the topology, unique ID of the topology, status of the topology, uptime, number of workers assigned to the topology, and so on. The possible values of the Status fields are ACTIVE, KILLED, and INACTIVE.

Let's click on SampleStormClusterTopology to view its detailed statistics. There are two screenshots for this. The first one contains the information about the number of workers, executors, and tasks assigned to the SampleStormClusterTopology topology:

The next screenshot contains information about the spouts and bolts, including the number of executors and tasks assigned to each spout and bolt:

The information shown in the previous screenshots is as follows:

• Topology stats: This section will give information about the number of tuples emitted, transferred, and acknowledged, the capacity latency, and so on, within the windows of 10 minutes, 3 hours, 1 day, and since the start of the topology
• Spouts (All time): This section shows the statistics of all the spouts running inside the topology
• Bolts (All time): This section shows the statistics of all the bolts running inside the topology
• Topology actions: This section allows us to perform activate, deactivate, rebalance, kill, and other operations on the topologies directly through the Storm UI:
  • Deactivate: Click on Deactivate to deactivate the topology. Once the topology is deactivated, the spout stops emitting tuples and the status of the topology changes to INACTIVE on the Storm UI.

• • Activate: Click on the Activate button to activate the topology. Once the topology is activated, the spout again starts emitting tuples.
  • Kill: Click on the Kill button to destroy/kill the topology. Once the topology is killed, it will free all the Storm resources allotted to this topology. While killing the topology, the Storm will first deactivate the spouts and wait for the kill time mentioned on the alerts box so that the bolts have a chance to finish the processing of the tuples emitted by the spouts before the kill command. The following screenshot shows how we can kill the topology through the Storm UI:

Let's go to the Storm UI's home page to check the status of SampleStormClusterToplogy, as shown in the following screenshot: