When task or gateway nodes in your E-MapReduce (EMR) cluster sit idle, scale in the cluster to reduce compute costs.
Prerequisites
Before you begin, make sure that:
A cluster exists on the EMR on ECS page. See Create a cluster.
Limitations
Task nodes
To scale in task nodes, the cluster must meet all of the following requirements:
| Requirement | Value |
|---|---|
| EMR version | V5.X later than V5.6.0, or V3.X later than V3.2.0 |
| Cluster state | Running |
| Billing method of the task node group | Pay-As-You-Go or Preemptible Instance |
Gateway nodes
To scale in gateway nodes, the cluster must meet all of the following requirements:
| Requirement | Value |
|---|---|
| EMR version | V5.X later than V5.10.1 |
| Cluster state | Running |
| Billing method of the gateway node group | Pay-As-You-Go |
Hadoop clusters
For Hadoop clusters, you cannot scale in a node group that was created on the Auto Scaling tab. See Configure auto scaling (only for Hadoop clusters).
Scale in a task or gateway node group
Log on to the EMR console. In the left-side navigation pane, click EMR on ECS.
In the top navigation bar, select the region where your cluster resides and select a resource group.
On the EMR on ECS page, find your cluster and click Nodes in the Actions column.
On the Nodes tab, click Scale In in the Actions column of the node group you want to reduce.
In the Scale In dialog box, adjust the Reserved Quantity field — click the downward arrow or type a number directly.
Click OK.
Other ways to scale in
| Method | Reference |
|---|---|
| API | DecreaseNodes |
What's next
To reduce core nodes instead, see Scale in a core node group.
For cluster scale-in FAQ, see FAQ about cluster management.