How do I resolve Tez web UI error "Adapter operation failed » Timeline server (ATS) is out of reach" on Amazon EMR?

Last updated: 2019-06-24

How can I resolve the Tez web UI error "Adapter operation failed » Timeline server (ATS) is out of reach. Either it's down, or CORS is not enabled." on Amazon EMR release version 5.20.0 or 5.21.0?


In Amazon EMR release versions 5.20.0 and 5.21.0, the Tez UI makes requests to the YARN timeline server using localhost instead of the hostname of the master node. To resolve this error, upgrade to the latest Amazon EMR release version.

To continue using release version 5.20.0 or 5.21.0, run the following script directly on the master node or as an Amazon EMR step. You can also launch a new cluster and then run the script as a custom bootstrap action. The script modifies the Tez UI configuration to use the hostname of the master node instead of localhost. The script doesn't take any arguments. It logs results in /tmp/fix_tez_ui_0-9-1.log.

Script location:

  • For us-east-1: s3://
  • For all other Regions: s3:// Replace Region with your Region code.

After you run the script, clear the browser cache to be sure that the browser uses the updated configs.env file.

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