[jayd16]

Btw, do any good, modern CI tools support incremental rollout of multiple in-flight changes on monoliths? As in patch A is live, team B wants to rollout A+B and team C wants to rollout A+C. Ideally, A+B+C will eventually go live.

Do cloud/paas providers deeply support this flow anymore? Every dashboard would need to compare across multiple live versions and I haven't tried that in a while.

[bunderbunder]

I'd say this is a job for feature flags. That way you always have exactly one live version of the code, but still retain the ability to hide WIP from users until it's ready.

If you're instead doing this with feature branches or something like that, then by definition you don't have CI. You have NI: Never Integration.

Because, to an approximation, there's never any point in time where all of the code you're working on is integrated together so that everyone has a chance to see how what they're doing interacts with what everyone else is doing. And yes, it is possible for a branch to successfully auto-merge and produce something that compiles and passes all automated tests, and still introduce a horrible regression defect because of an unanticipated interaction between two different changes on two different feature branches. I don't see it happen often, but when it does it usually creates such a big production SNAFU that even once every 5 years is still way too often for my taste.

[jayd16]

I don't dispute that good CI is facilitated by committing early and often but difference do feature flags really make? You still need to roll out features whether you tie that to versions or not.

If you're looking for performance regressions as you roll out feature flags, do you get any kind of support for that from built in dashboards? How do you get clean metrics if you only have one version and a bunch of teams turning knobs?

SOA/Microservices have a lot of headaches but you do get the option for very tightly scoped deployments or feature rollouts.

[anonymars]

Wouldn't these just be different branches?

[jayd16]

I'm referring to rolling out multiple merge downs (possibly from branches) from across the entire org into a monolithic deploy.