You may look at  /mnt/var/lib/info/ on Master node to find lot of info about your EMR cluster setup.

More specifically /mnt/var/lib/info/job-flow.json contains the jobFlowId or ClusterID.

I was able to install a JSON parser on my Master node to retrieve jobFlowID.

# Install JSON PARSER

Install pkgs required for jsawk

wget http://pkgs.repoforge.org/js/js-1.60-1.el6.rf.x86_64.rpm wget http://pkgs.repoforge.org/js/js-devel-1.60-1.el6.rf.x86_64.rpm sudo yum install -y js-1.60-1.el6.rf.x86_64.rpm sudo yum install -y js-devel-1.60-1.el6.rf.x86_64.rpm

Install JSAWK curl -L http://github.com/micha/jsawk/raw/master/jsawk > jsawk

chmod 755 jsawk && sudo mv jsawk /usr/bin/

Parse and print job flow ID

jsawk ‘return this.jobFlowId’ < /mnt/var/lib/info/job-flow.json