Managing the Job Tracker using dsetool commands 

Examples for using dsetool commands to identify and manage Job Tracker nodes.

Several dsetool commands are useful for managing Job Tracker nodes:
  • dsetool autojt datacenter

    If you do not specify the data center name, the command elects Job Trackers for all data centers. Automatically manage Job Tracker selection and remove manual selections. If the current manually selected tracker is up, the manually selected Job Tracker continues to be used.

  • dsetool jobtracker

    Returns the Job Tracker hostname and port to your location in the data center where you issued the command.

  • dsetool setjt node IP

    Moves the Job Tracker, or the Spark Master, and notifies the Task Tracker nodes of the change.

  • dsetool setrjt node IP

    Moves the reserve Job Tracker and notifies the Task Tracker nodes of the change.

  • dsetool sparkmaster

    For SparkMaster only. Returns the Job Tracker hostname and port to your location in the data center where you issued the command.

  • dsetool listjt

    Lists all Job Tracker nodes grouped by their local data center.

  • dsetool ring

    Lists the nodes and types of the nodes in the ring and the following Job Tracker status:

    • (JT) the active Job Tracker
    • (PT) an inactive primary tracker, when the primary tracker is down
    • (RT) an inactive reserve tracker, when the reserve tracker is up while there is a primary tracker
These dsetool commands also work for Spark Master, except for dsetool jobtracker. The Spark Master equivalent command is dsetool sparkmaster.

More dsetool commands and options are described later.

Listing Job Trackers example

To determine which nodes in your DataStax Enterprise cluster are Job Tracker nodes, run the following command:

  • Installer-Services and Package installations:
    $ dsetool jobtracker
  • Installer-No Services and Tarball installations:
    $ install_location/bin/dsetool jobtracker

Moving the Job Tracker node example

If your primary Job Tracker node fails, move the Job Tracker to another analytics node in the cluster. In-progress MapReduce jobs fail when you move the Job Tracker node or when the node goes down.

Procedure

  1. Log in to a DataStax Enterprise analytics node.
  2. Run the dsetool setjt command and specify the IP address of the new Job Tracker node in your DataStax Enterprise cluster. For example, to move the Job Tracker to node 110.82.155.4:
    • Installer-Services and Package installations:
      $ dsetool setjt 110.82.155.4
    • Installer-No Services and Tarball installations:
      $ install_location/bin/dsetool setjt 110.82.155.4
  3. Allow 20 seconds for all of the analytics nodes to detect the change and restart their Task Tracker processes.
  4. In a browser, connect to the new Job Tracker node and confirm that it is up and running. For example (change the IP to reflect your Job Tracker node IP):
    http://110.82.155.4:50030
  5. If you are running Hive or Pig MapReduce clients, restart them to pick up the new Job Tracker node information.