Where do I find the logs of the job executions when running on my Cluster?

The logs are in the directory /tmp/fire/workflowlogs on the machine on which the Fire server is running:

Each workflow execution has its own log file.

The JSON representation of the workflow is in /tmp/fire/workflows when running in YARN client mode. They are in .fireStaging directory under the users home directory on HDFS when running in YARN cluster mode.