Zero Downtime Deployο
Zero downtime deploys refer to being able to re-deploy a service without having any noticeable impact on clients. Correspondingly, you should also not have any increase in error rates in logs, monitoring etc.
Why is it Important?ο
Errors received by customers or connected services are undesirable, and use up your error budget
Alerts or errors that will be ignored (as they are caused by the release) can lead to complacency which makes it hard to see real issues quickly
Service downtime leads to stampeding traffic and other cascading issues that can make small errors much worse