This topic describes how to reduce the number of task nodes to scale in an E-MapReduce (EMR) cluster.


An EMR cluster is created. For more information, see Create a cluster.


You can reduce only the number of task nodes to scale in an EMR cluster. The cluster you want to scale in must meet the following requirements:
  • The EMR version is V2.X later than V2.5.0 or V3.X later than V3.2.0.
  • The cluster is in the Idle or Running state.
  • The billing method of the cluster is pay-as-you-go.


  1. Go to the Cluster Overview page.
    1. Log on to the Alibaba Cloud EMR console.
    2. In the top navigation bar, select the region where your cluster resides and select a resource group based on your business requirements.
    3. Click the Cluster Management tab.
    4. On the Cluster Management page, find your cluster and click Details in the Actions column.
  2. On the Cluster Overview page, choose Change Configuration > Scale In in the upper-right corner.
  3. In the Scale In dialog box, click the downward arrow for Reserved Nodes or enter a number in this field to reduce the number of task nodes.
  4. Click Scale In.
  5. In the Confirm Scale-in Activity message, click OK.