Amazon EMR now supports placing your EMR master nodes in distinct racks to reduce risk of simultaneous failure
Amazon EMR now supports a spread placement group strategy for clusters with multiple master nodes. You can now launch master nodes across separate underlying hardware to reduce the risk of simultaneous failures that might occur when instances share the same racks. Earlier, master nodes were placed within the same subnet without any placement strategies.
To use this feature, you need to attach the placement group managed policy to the EMR role, and launch the cluster with the placement-group-configs parameter.
Amazon EMR support for spread placement strategy for master nodes is now generally available on Amazon EMR Release Versions 5.23.0 and above, and in all commercial AWS Regions where Amazon EMR is available. To get started, please refer to the documentation.