When the computing resources or storage resources of an E-MapReduce (EMR) cluster are insufficient, you can horizontally scale out the cluster. This article describes how to scale out a cluster.

Limits #

• Clusters with high availability enabled support scaling the Primary node group, Core node group, and Task node group.
• Clusters without high availability enabled support scaling only the Core node group and Task node group.
• The configuration of newly added nodes during scaling matches that of existing nodes by default.

Procedure #

1. Log in to EMR Console
2. In the left navigation pane, click Resource Management > on ECS > Cluster Details > Nodes, to go to the Nodes page.
3. Click the Expansion button in the operation column of the target node group.
   
4. In the scale-out dialog box, configure the scale-out settings and specify the number of nodes after scaling out.
5. Select the checkbox to agree to the E-MapReduce service terms, and click the Confirm button to submit. The scale-out operation is then complete.

   tip

   After the cluster is scaled out, some service parameters will be dynamically adjusted due to changes in cluster resources. Follow the prompts on the interface to restart the relevant services for the changes to take effect.