Systems Manual

The Ambari web based tool can be started opening a browser on the head node and entering http:/localhost:8080. After login (password is provided by Limulus Computing) The Ambari Control panel similar to the image below will be displayed.

The left side menu allows the values services and nodes of the cluster to be viewed. An example of the the HDFS (Hadoop Distributed File System) is shown in the following figure:

The Limulus hosts can be displayed by selecting the Hosts item on the left side menu.

The Limulus Hadoop design requires that the headnode (login node) and n0 operates in multiple roles. The headnode runs the bulk of these services and has extra memory for this purpose. All nodes,however operated and a HSDS and YARN client, which means they all participate in the distributed HDFS storage and running MapReduce and Spark jobs. This default behavior may need to be adjusted depending on your requirements. (i.e. the number of YARN jobs on the headnode may be reduced or eliminated).

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Ambari has been configured to start all the cluster services when the system starts. If a service failed to start or is having issues, a read or orange dot will be shown next to the service name in the Services section. Functioning services have a green dot.

Best practices dictate that al the Hadoop services are shutdown gracefully. Ambari provides a full system shutdown option. Click the three dots next to Services in the left side vertical menu and select “Stop All.” The shutdown is “graceful” an will take some time. (Do not be concerned with all the service alerts, these are normal when services startup of shutdown)

After all the services are stopped, the entire cluster may be powered-off by shutting down the head node (nodes gracefully shutdown when the headnode is powered-off using the poweroff command or the desktop interface. (avoid just pressing the power button).