Hello,
First you need to find process id by executing command 'ps x'. Once you have found it you can stop the process by using 'kill *processid*' or force stop it using 'kill -9 *processid*'.
To start Cloud Node back again find name of executable and run it using this command './*execname*'
You can also refer to this for more information: https://www.linux.com/training-tutorials/how-kill-process-command-line/
Best Regards,
David Delač