Implementation details are going to be an exercise for the organization. But if you start from the wrong guiding principles (or no principles at all), you're going to end up with a lot of avoidable mistakes and pointless middle-of-the-night bridge calls.

Excellently stated. I had a discussion on /r/syaadmin a few weeks ago about I take my role as a PM to an interesting place.

In addition to keeping the project and developers on task, I'm anal about making sure our agile tools are NOT a chore to use. They should feel as natural to interact with as a mouse and as nonobtrusive to the workflow as adding lines to a text file.

Principle here for us is to make our entire ops wheelhouse as frictionless as possible.

Someone should write a retrospective on the Twelve-Factor App. Have these guiding operational principles changed with the technology / available network bandwidth?

12 factor is hard because it's a guiding philosophy and has shades rather than just being there or not there. Each factor needs to be looked at for each app. It takes time and experience to actually see 12 factor violations as real problems. Actually implementing 12 factor in an application requires a lot more work than just importing a library or choosing a stack. Developers get more excited about features than they do about infrastructure and so don't spend as much time as they should thinking about making refinements.

At my current job, three microservices exist in one code repository. Because of this, continuous integration makes one build of all three services rather than three builds. The CI service doesn't provision for different environment variables per build, so the app has to take the config for the CI environment from the codebase. This is recognized as a problem, but not enough of one to get a unanimous consensus on doing the work to change it. I want to change it now, because I know from experience that it's better to rip the bandaid off of architectural problems because it's only going to get harder to fix as time goes on. Also because it affects my daily workflow in weird ways.