...
For Max Idle Time, consider cost vs availability of the cluster for reuse. The higher the value for Max Idle Time, the more clusters will be sitting idle ready for a run. Starting in CDAP 6.6.0, the default Max Idle Time is 30 minutes.
Step 2. For CDAP 6.5.x only, set system.profile.properties.clusterReuseEnabled runtime argument to true
...