Enabling Resource manager HA using Ambari

In this article , We will learn how to enable Resource manager (RM) High availability (HA) using Apache Ambari. In resource manager high availability, the Hadoop cluster will have two or more resource managers. One resource manager will be active and other resource managers will be standby.

The active resource manager is responsible for serving user requests. if the active resource manager goes down, one of the Standby resource managers will become an active resource manager and will serve the user requests without failing running jobs.
 
By default HDP comes with a single resource manager without HA, We need to install one more resource manager and modify/add properties to enable Resource manager HA.

1) Confirm No HA is enabled

Go to Ambari home page ---> click on YARN --->Summary

If no HA is enabled for resource manager, You will see only one resource manager as shown in the below picture.

2) Click enable RM HA

Click on enable Resource Manager HA under service actions to initiate enabling RM HA.


Go to Ambari home page ------->click YARN-------> click Service actions -------> click enable Resource Manager HA

The picture below shows enable Resource Manager HA option.

3) Getting started

Ambari opens a new HA wizard that will walk us through enabling  RM HA. We need downtime for  cluster to enable HA.  1 hour  down time is recommended .depending on the cluster size, You can plan for more down time.


This is information step , read and click next.

4) Select Host

We need to have one more resource manager for HA. We will select a node to install one more resource manager  in this step. Click next once a node is selected.

In the picture below , I have selected node master2 to install one more resource manager.

5) Review

This is a review step. We can go back to previous step if we want to modify anything. The picture below show additional resource manager is going to be installed on master2 node.

We can go back and modify if we want to modify that node to something else. Else just click Next.

Some new properties need to be added/modified to YARN to enable resource manager HA. This step will show you all properties to be modified/added.

6) Configure components

This step performs 5 operations .

    Amabri stops all required services to enable HA.

    Installs new resource manager on selected node.

    Adds/modifies YARN configuration for HA

   Adds/modifies HDFS configurations for RM HA

   Start all services.

You can click on operations to see logs.

Once all operations are completed, Click Next.

7) Confirm active and standby

Amabri reloads after completing RM HA , We can see two resource managers. One resource manager will be active and other will be standby.

The picture below shows two resource mangers and we can confirm RM HA is enabled.

Let me know if you have any questions about enabling RM HA using Ambari.