To add to this, you want you application to be stateless and immutable. This makes your life so much easier in so many different ways: (1) You can know exactl

To add to this, you want you application to be stateless and immutable. This makes your life so much easier in so many different ways: (1) You can know exactly what code was running when debugging past issues (2) Scaling can be done dynamically and relatively easy. Just turn on/off application nodes. (3) Rollbacks are (relatively) trivial. Just go back to the know good immutable version (4) Memory leaks can be "solved" by restarting nodes every so often (5) If, for whatever reason, your application node dies you shrug your shoulders and start a new one Once you add DBs with state to your application all of become much harder. You want that state in something that's rock solid and rarely changes to avoid all the above problems.