In a few words, the idea of canary releases is to deliver a new software version to only a fraction of the users, analyze the results, and decide whether to proceed further or not. If results are not aligned with expectations, roll back; if they are, increase the number of users exposed until all users benefit from the new version.
In this post, I'd like to detail this introduction briefly, explain different ways to define the fraction, and show how to execute it with Apache APISIX.