Yes, clustering and virtualizing things is pretty much how this has been handled at a scale, be it modern web applications, (Open)VMS or mainframes. It's simple

Yes, clustering and virtualizing things is pretty much how this has been handled at a scale, be it modern web applications, (Open)VMS or mainframes. It's simpler and has other advantages to architect the application for this than to do the custom integration work required to make it work on a process/application level.