The correct way to do it is as follows. 1) Set up a test environment using puppet or whatever that boots up an image instance and deploys your whole stack to y

The correct way to do it is as follows. 1) Set up a test environment using puppet or whatever that boots up an image instance and deploys your whole stack to your cloud provider. 2) Deploy your release candidate to this environment. 3) Run some smoke tests, acceptance tests and maybe even a few performance tests against this environment. 4) If all the tests pass store your image somewhere (S3, GitHub) also make sure to tag the image with your release candidate version. 5) You can now deploy this change-set to your production environment. When things go wrong you will have fully configured servers available almost immediately. Now granted this is potentially a very long running process but you could simply set this up as a nightly build.