Description
Hey, starting a discussion since I haven't found anything related in the Open issues. So I'm currently running on Kubernetes provider and we are soon to switch to Istio for canaries. However, one thing that strikes me as odd is that Flagger does not allow instant rollback.
What I would like to see is after the promotion is finished, the old version scales down to a minimum, but keeps running. Basically this also requires some means to promote this old version back to primary so obviously it's not that simple. However, I think even if it's something as low-level as applying labels with kubectl, I'm fine with that, as long as it works.
I understand that the basic purpose of Flagger is canary, which by definition probably does not have a notion of a rollback. However, in real scenarios even if all your tests and gates pass, you might still want to roll it back e.g. for some business reasons like the release was rolled out too early by mistake.
What are the community thoughts on this? Maybe there are some existing solutions to this problem? If not I really think that this is a feature that would be great to have in Flagger.