You can now modify the configuration of applications running on EMR clusters including Apache Hadoop, Apache Spark, Apache Hive, and Hue without re-starting the cluster. EMR Application Reconfiguration allows you to modify applications on the fly without needing to shut- down or recreate the cluster. Amazon EMR will apply your new configurations and gracefully restart the reconfigured application. Configurations can be applied through the Console, SDK, or CLI. Please visit Configuring Applications to learn more about this feature.
This feature is now available from EMR release 5.21.0 in all supported regions for Amazon EMR.
You can stay up to date on EMR releases by subscribing to the feed for EMR release notes. Use the icon at the top of the EMR Release Guide to link the feed URL directly to your favorite feed reader.
from What’s New https://aws.amazon.com/about-aws/whats-new/2019/05/amazon-emr-announces-support-for-reconfiguring-applications-on-running-emr-clusters/