This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
When the web-application is distributed across TWO VMs :
Everything except the 'HttpSession' is duplicated on the other VM. 'HttpSession' objects(including their attributes) 'move' from one VM to another. 'HttpSession' live in only ONE place at any given moment, so same session ID for a given web app will NEVER appear in two VMs at the same time.