[siliconc0w]

It's nice to have a lot of options when managing deployments. Feature flags, canary deploys, A/B or green/blue, etc. Canaries are really nice to catch the majority of deploy issues (i.e 'it doesn't start up' errors, obvious exception spikes or performance regressions). Feature flags let you hand off control to individual product teams and encourage them to create 'bite sized' changes which can be flagged. Blue/green is also a nice way to reduce risk given more complicated cross-service changes where having another 'known good' copy of production around is helpful.

[spladug]

Feature flags are super useful. We didn't really have room to cover our use of them in this post, but if you're curious you can see the system we currently use for it here: https://github.com/reddit/reddit/blob/master/r2/r2/config/fe...