I posted this also in Stack Overflow:
hi i am running a google cloud compute instance as a debian jessie machine. i installed apache and java via apt-get and tomcat via wget from the tomcat repository. the instance is running and not stopped. ever since i installed the packages, i notice that at one point, some of the features i installed are removed. in tomcat, the manager directory is deleted and with it the capability to remote manage the server via the web interface. also, a WAR i deployed is also deleted. why is this happening? i need to constantly remove and re-install the tomcat and re-deploy the WAR file.
is this something related to a snapshot i took of the instance? though when i played with this snapshot, manager application was available under tomcat ROOT.
this is very frustrating. any ideas?