Rolling Updates with Deployments

Let's take a closer look at rolling updates and rollbacks.

Rolling updates

Deployments are amazing at zero-downtime rolling updates (rollouts). But they work best if we design our apps to be:

1. Loosely coupled via APIs

2. Backward and forward-compatible

Both are hallmarks of modern cloud-native microservices apps and work as follows.

Our microservices should always be loosely coupled and only communicate via well-defined APIs. Doing this means we can update and patch any microservice without having to worry about impacting others — all connections are via formalized APIs that expose documented interfaces and hide specifics.

Ensuring releases are backward and forward-compatible means we can perform independent updates without caring which versions of clients are consuming the ...