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    E-MapReduce:Node compensation

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    E-MapReduce:Node compensation

    Last Updated:Mar 26, 2026

    When E-MapReduce (EMR) detects that an Elastic Compute Service (ECS) instance can no longer support normal engine service operation, it automatically resolves the issue. The resolution method depends on the billing method of the affected instance:

    • Pay-as-you-go task instances: EMR purchases a replacement ECS instance automatically.

    • Subscription task instances: EMR redeploys the faulty instance in place.

    Starting 18:00 (UTC+8) on July 10, 2023, automatic compensation is turned on by default for new pay-as-you-go task node groups.

    Prerequisites

    Before you begin, ensure that you have:

    • A DataLake cluster, a Dataflow cluster, or a custom cluster with the YARN service deployed. For more information, see Create a cluster.

    Limits

    Only task node groups support automatic compensation.

    When automatic compensation may fail

    Automatic compensation may not complete in the following situations:

    • A system issue occurs on the ECS instance to be replaced.

    • Release protection is enabled on the ECS instance to be replaced.

    • The number of nodes in the node group is at or below the minimum number of nodes reserved for that group.

    During scale-out, the bootstrap action script runs automatically on new ECS instances. If the instance being replaced had manually deployed components or services, redeploy them on the new instance after the replacement completes.

    Enable or disable automatic compensation

    1. Log on to the EMR console. In the left-side navigation pane, click EMR on ECS.

    2. In the top navigation bar, select the region where your cluster resides and select a resource group.

    3. Find your cluster and click Nodes in the Actions column.

    4. On the Nodes tab, click the name of the node group in the Node Group Name / ID column.

    5. In the Node Group Attributes panel, turn on or turn off Automatic Compensation.

    6. In the confirmation dialog, click OK.

    7. Click Save.

    Check automatic compensation status

    On the Nodes tab, if you have enabled automatic compensation and compensation has been performed on a node group within the past week, the number of times compensation ran is displayed in the Automatic Supplementation column. Move the pointer over the count and click View event details to view the details.