The YARN ResourceManager is responsible for tracking the resources in a cluster and scheduling applications. Before CDH 5, the ResourceManager was a single point of failure in a YARN cluster. If Resource manager is down, then none of the jobs will run in the cluster.
The ResourceManager high availability (HA) feature adds redundancy in the form of an active-standby RM pair to remove this single point of failure. Furthermore, upon failover from the active RM to the standby, the applications can resume from the last state saved than restarting again from the start.
The process of setting RM HA is similar to the Namenode HA.
To enable Resource Manager HA, go to YARN – Actions – Enable/Select high availability
Select two hosts in which you want to run Resource Manager. Please ensure that the configuration of both hosts are similar.
Once it finish, go to Yarn – instances section, you can see the two resource managers listed and one would be active and another would be standby as you have specified during the hosts selection.
Thus we covered how to configure Resource Manager HA.
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