EMR master instance is not reachable
I faced a rare issue today. My EMR cluster was not resizing. Apparently, the master node was facing issue in communicating with EMR. The cluster status showed "Master instance is not reachable. Please check your master instance status". But I was able to login into master node and use hadoop and HDFS without any issues. Just that the cluster was not resizing. Searching on the internet just gave one relevant result. https://forums.aws.amazon.com/thread.jspa?messageID=695687 Although it mentioned that the issue was with the emr 3.x amis and my cluster was a 4.x, I thought this was the same issue. For verifying I checked on my other clusters if any such service was running on them. $ ps awux | grep instancecontroller hadoop 2389 0.4 2.0 3584132 309980 ? Sl Apr13 97:41 /etc/alternatives/jre/bin/java -Xmx1024m -XX:OnOutOfMemoryError=kill -9 %p -XX:MinHeapFreeRatio=10 -server -cp /usr/share/aws/emr/instance-controller/lib/*:/home/hadoop/conf -Dl