A very light weight VM at application level and can be started/cloned in place

existing VM are all need to start up some wrapper environment to seperate guest OS/app from each other, to achive security.
But some time I dont need such full scale mechnism, I only need to seperate different running of application.
For example, I need to install formality that need some old system wide setting and old libray , and I dont want these setting to affect others,I dont want to do any special setting, I just want to

1. firstly make a clone of existing setting ,this step need to be very cheap
   
2. and do all change on this clone, such as install app, and related lib
3. I can chose to merge it into origin environment.