Issue:
When a user tries to restart the SDC from the UI, it is not working for some installations. The SDC only stops but does not start back.
Answer:
This is actually a known limitation for the installation types where the StreamSets Data Collector does not start the process. This can happen with Cloudera Manager, or RPM installation (also tarball installation run as a service) running on a system using Systemd Init.
Therefore after trying to restart the SDC from the SDC UI, the SDC stops, but it can't start again.
This limitation exists because under such installations, the SDC process requires a different user to initiate the start which is not possible without appropriate authentication.