Add core nodes or task nodes to an E-MapReduce (EMR) cluster when computing or storage resources fall short. Scale-out does not restart application processes on existing nodes.
Prerequisites
Before you begin, ensure that you have:
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An EMR cluster. See Create a cluster
Limitations
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You can only add core nodes and task nodes. The master node group cannot be scaled out.
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New nodes inherit the configuration of existing nodes in the same node group.
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For Hadoop clusters, you cannot scale out a node group that was created on the Auto Scaling tab. See Configure auto scaling (only for Hadoop clusters).
Usage notes
StarRocks clusters: If your cluster contains StarRocks that was manually upgraded, scaling out may cause version inconsistency. Migrate your data and tasks to EMR Serverless StarRocks, which is compatible with open-source StarRocks and supports automatic upgrades.
Scale out a cluster
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Log on to the EMR console. In the left-side navigation pane, click EMR on ECS.
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In the top navigation bar, select the region where your cluster resides and select a resource group.
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On the EMR on ECS page, find the cluster and click Nodes in the Actions column.
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On the Nodes tab, find the node group to scale out and click Scale Out in the Actions column.
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In the Scale Out dialog box, configure the following parameters.
Parameter Description Node Group Name The name of the node group. Node Type The type of the node group. Current Instance Type The information about instances in the node group. Billing Method The billing method inherited from the cluster. Cannot be changed. If the billing method is Subscription, you can enable Auto-renewal and set the Subscription Duration for new nodes. After you enable auto-renewal, nodes are automatically renewed 7 days before expiration. The default renewal period is one month. You can change the renewal period or disable auto-renewal on the Auto-renewal page. vSwitch The vSwitch configured for the node group. Current Quantity The number of instances currently in the node group. Added Instances The number of instances to add. Click the arrow or enter a number. Cluster Expiration Time The expiration time of the subscription cluster. Terms of Service Read and agree to the terms before proceeding. -
Click OK.
To log on to a newly added node, see Log on to a cluster.
What's next
After scaling out a core node group that uses Hadoop Distributed File System (HDFS) for storage, data distribution across DataNodes may become unbalanced. Run HDFS Balancer to redistribute the data. See HDFS Balancer.
References
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Upgrade instance configurations: If the vCPUs or memory of Elastic Compute Service (ECS) instances in a node group no longer meet your needs, upgrade the instance type. See Upgrade node configurations.
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Expand storage: To expand data disks for EMR clusters, see Expand a disk.
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Troubleshoot scale-out issues: See FAQ about cluster management.
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Scale out via API: Use the IncreaseNodes operation to scale out programmatically.