Correct, and it's fair to say that the application pretty much is the image - if the application exits, the VM shuts down. Configuration can be kept out of the

Correct, and it's fair to say that the application pretty much is the image - if the application exits, the VM shuts down. Configuration can be kept out of the image with cloud-init, and I basically treat all images as immutable. The majority of my experience has been using OSv, running Akka, and it's yielding excellent results. Image sizes are small (<200MB), easy enough to upload to AWS and create a new AMI in a few minutes. Boot time to a running application is a few seconds. The only possibly downside is that OSv (as yet) doesn't support paravirtualisation, only HVM.