Step 4: Launch Drill Under YARN

Now that the Drill and YARN configuration is complete, you can issue the start command from the Drill-on-YARN client to launch Drill under YARN. Launching Drill-on-YARN from the client starts Drill and brings Drill up on other nodes.

Issuing the start command starts the YARN Application Master, which then works with YARN to start the drillbits. The Application Master provides a web UI to monitor the cluster.
Note: To simplify debugging, you can set the cluster size to a single node. Once you confirm that a single node works, increase the node count.
Launch Drill under YARN as the "mapr" user. For example, if you installed Drill as “mapr,” launch Drill as the mapr user.
Note: If you launch Drill as “root” and the system returns an error failing the launch attempt, launch Drill as a whitelisted user, such as “mapr.”
Issue the following command to start Drill under YARN:
$DRILL_HOME/bin/drill-on-yarn.sh --site $DRILL_SITE start
Note: To avoid typing the site argument each time you launch Drill under YARN, set an environment variable:
export DRILL_CONF_DIR=$DRILL_SITE
$DRILL_HOME/bin/drill-on-yarn.sh start
After you issue the start command, a number of lines describing the startup process prints. The tool automatically archives and uploads the site directory, which YARN copies (along with the Drill software) onto each node. A URL that includes both the host and the port number displays. Enter the URL in a web browser to access the Application Master web UI.
Note: When you launch Drill from the Drill-on-YARN client, the Application Master can come up on any node. Save the provided URL to share with other users so they can also access the Application Master. Alternatively, you can run the status command to see the URL or go to the YARN Resource Manager UI to get the link.

See Drill-on-YARN Command Line Tool for additional commands, including stop, status, and resize. See Application Master Web UI for cluster monitoring information.