Amazon EMR provides several tools to monitor the performance of your cluster.
Hadoop Web Interfaces Every cluster publishes a set of web interfaces on the master node that contain information aboutthe cluster. You can access these web pages by using an SSH tunnel to connect them on the masternode. For more information, see View Web Interfaces Hosted on Amazon EMR Clusters.
CloudWatch Metrics Every cluster reports metrics to CloudWatch. CloudWatch is a web service that tracks metrics, andwhich you can use to set alarms on those metrics. For more information, see Monitor Metrics withCloudWatch.
Ganglia Ganglia is a cluster monitoring tool. To have this available, you have to install Ganglia on the clusterwhen you launch it. After you've done so, you can monitor the cluster as it runs by using an SSHtunnel to connect to the Ganglia UI running on the master node. For more information, see MonitorPerformance with Ganglia. Reference: http://docs.aws.amazon.com/ElasticMapReduce/latest/DeveloperGuide/emrtroubleshoot-tools.html