Amazon EMR
Management Guide

Step 3: Look at the Last State Change

The last state change provides information about what occurred the last time the cluster changed state. This often has information that can tell you what went wrong as a cluster changes state to FAILED. For example, if you launch a streaming cluster and specify an output location that already exists in Amazon S3, the cluster will fail with a last state change of "Streaming output directory already exists".

You can locate the last state change value from the console by viewing the details pane for the cluster, from the CLI using the list-steps or describe-cluster arguments, or from the API using the DescribeCluster and ListSteps actions. For more information, see View Cluster Details.