Not terribly easy, but possible. I agree that "never have to SSH" is a bad target because there will always be edge cases, but for the majority of things it's possible to troubleshoot at the cluster level given immutable infrastructure; all the systems will be doing the exact same thing given an input. Reality shows that this is a bit idealistic, but if you start finding that e.g. A certain set of requests cause weird behavior, you can look at what makes those requests different, then set up some routing logic to send them to a debug farm (using something like https://github.com/Netflix/zuul ).
http://techblog.netflix.com/2012/06/scalable-logging-and-tra...
https://github.com/Netflix/vector
Not terribly easy, but possible. I agree that "never have to SSH" is a bad target because there will always be edge cases, but for the majority of things it's possible to troubleshoot at the cluster level given immutable infrastructure; all the systems will be doing the exact same thing given an input. Reality shows that this is a bit idealistic, but if you start finding that e.g. A certain set of requests cause weird behavior, you can look at what makes those requests different, then set up some routing logic to send them to a debug farm (using something like https://github.com/Netflix/zuul ).