If OneClick server is running in a stable state, on OneClick server there will be a stable.txt file automatically created under $SPECROOT\tomcat\webapps\spectrum directory. The content of this file is the followings:
This is an automatically generated file which indicates tomcat process is currently in stable state. Should tomcat experience catastrophic error such as an out of memory error, the file will be automatically deleted. The file will be recreated upon tomcat restart. Load balancer status checking which performs periodic checks on the health of a server shouldperform a GET on this stable file http://<host>:<port>/spectrum/stable. Failure to retrieve the file indicates either tomcat is not running or poor health of the tomcat process.
If OneClick server is not running or poor health, this stable.txt file would not exist under $SPECROOT\tomcat\webapps\spectrum directory.