Creating and Modifying Clusters with the Cloudera Director Web UI

1. Log in to Cloudera Director at http://director-server-hostname:7189. Cloudera Director opens on the All Environments page, which displays the current environments, deployments, and clusters. Click the cluster you want to modify.
2. Click Modify Cluster to the right of the cluster name. The Modify Cluster page displays the gateway, masters, and workers instance groups and any additional instance groups that have been added to the cluster, with the current number of instances in each instance group.
3. You can add instances to an existing instance group or create a new instance group and add roles to it.
   • To add instances to an existing instance group, click Edit to the right of the instance group and click the up or down arrows in the Add Instances section to increase the number of workers and gateways to the desired size. Each new instance will contain the same roles as the existing instances of that group.
   • To create a new instance group, click Add Group, enter a name for the instance group, assign roles to it, select an instance template, and click the up or down arrows to choose the desired number of instances of that group to add.
4. Click Continue to confirm, and add the new instances or group to the cluster.

1. Log in to Cloudera Director at http://director-server-hostname:7189.

   Cloudera Director opens on the All Environments page, which displays the current environments, deployments, and clusters. Click the cluster you want to modify.

2. Click Modify Cluster to the right of the cluster name. The Modify Cluster page displays the gateway, masters, and workers instance groups and any additional instance groups that have been added to the cluster, with the current number of instances in each instance group.
3. You can remove an entire instance group, including all of its instances, or remove individual instances from an instance group:
   • To remove an entire instance group, click Delete Group at the right end of the row for that instance group.
   • To remove individual instances from an instance group, click Edit near the right end of the row for the instance group. Click the checkbox for each instance you want to remove, and click the Delete button. The instances you select display an action status of To be deleted.
4. Click OK to continue, Reset to unselect the selected instances and make a new selection, or Cancel to stop without making any changes.
5. Click Continue to confirm, and delete the selected instances.

After you add or remove instances from a cluster, HDFS data is likely to be distributed unevenly across DataNodes. Cloudera Director does not rebalance HDFS when you add instances or remove them from the cluster. If you need to rebalance the cluster, you must do so manually as described in HDFS Balancers in the Cloudera Manager documentation.

The need for rebalancing depends on the amount of data in HDFS and the number of instances added or removed during the cluster. Rebalancing is required only when there is a large movement of data. Cloudera recommends rebalancing the cluster through Cloudera Manager if you increase or reduce the number of DataNodes by 30% or more.