Today, we are excited to announce that Amazon EMR now publishes events for insufficient instance capacity. This launch makes it simpler for customers to troubleshoot EC2 instance capacity issues by providing them an easy way to view which instance types have insufficient capacity. Additionally, customers can use these events to create rules to be notified when there is insufficient instance capacity, as well as react to changes in their EMR cluster. These new events are automatically enabled for both current and earlier Amazon EMR on EC2 releases and no further action is needed.
Source:: Amazon AWS