Amazon EMR
Amazon EMR Release Guide

What's New?

This topic covers features and issues resolved in the current release of Amazon EMR. These release notes are also available on the Release 5.23.0 Tab, along with the application versions, component versions, and available configuration classifications for this release.

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For earlier release notes going back to release version 4.2.0, see Amazon EMR What's New History.

Release 5.23.0 (Latest)

New Amazon EMR release versions are made available in different regions over a period of several days, beginning with the first region on the initial release date. The latest release version may not be available in your region during this period.

The following release notes include information for Amazon EMR release version 5.23.0. Changes are relative to 5.22.0.

Initial release date: April 01, 2019

Last updated date: April 30, 2019

Upgrades

  • AWS SDK for Java 1.11.519

New Features

  • (April 30, 2019) With Amazon EMR 5.23.0 and later, you can launch a cluster with three master nodes to support high availability of applications like YARN Resource Manager, HDFS Name Node, Spark, Hive, and Ganglia. The master node is no longer a potential single point of failure with this feature. If one of the master nodes fails, Amazon EMR automatically fails over to a standby master node and replaces the failed master node with a new one with the same configuration and bootstrap actions. For more information, see Plan and Configure Master Nodes.

Known Issues

  • Tez UI

    Tez UI does not work on an EMR cluster with multiple master nodes.

  • Hue

    • Hue running on Amazon EMR does not support Solr. Beginning with Amazon EMR release version 5.20.0, a misconfiguration issue causes Solr to be enabled and a harmless error message to appear similar to the following:

      Solr server could not be contacted properly: HTTPConnectionPool('host=ip-xx-xx-xx-xx.ec2.internal', port=1978): Max retries exceeded with url: /solr/admin/info/system?user.name=hue&doAs=administrator&wt=json (Caused by NewConnectionError(': Failed to establish a new connection: [Errno 111] Connection refused',))

      To prevent the Solr error message from appearing:

      1. Connect to the master node command line using SSH.

      2. Use a text editor to open the hue.ini file. For example:

        sudo vim /etc/hue/conf/hue.ini

      3. Search for the term "appblacklist" and modify the line to the following:

        appblacklist = search
      4. Save your changes and restart Hue as shown in the following example:

        sudo stop hue; sudo start hue

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