Rebalancing a Hadoop cluster from Cloudera Manager

The Balancer tool available in Hadoop is used to balance the data blocks across all the datanodes when a new datanode is added or when an existing datanode reaches full capacity.

Adding the Balancer service to the cluster

Before you can rebalance a cluster, we need to add the balancer service. The following are the steps to add the Balancer service:

1. Navigate to the Clusters menu and select HDFS.

2. Click on the Instances tab and select Add to bring up the Customize Role Assignments screen as shown in the following screenshot:

   

3. Click on Select a host for the Balancer section to bring up the host selection screen as shown in the following screenshot. Select a host and click on OK. Here I have selected node4.

   

4. In the next screen, click on Continue. You should now see the Balancer service added, as shown in the following screenshot:

   

Rebalancing the cluster

Once the Balancer service is installed successfully, you can perform the rebalancing operation. The...