Theory

Theory: A Step is a Promise About Traffic or Replicas, Then a Pause

Canary steps are a state machine: setWeight/setCanaryScale, pause, analysis. Promotion advances; abort rewinds to stable.

Invariants

1. Pause without analysis is a human gate.
2. Inspection (kubectl argo rollouts get) reads that state machine.
3. Replica-based weight approximates traffic if pods are homogeneous.

setWeight 20 → pause → setWeight 50 → analysis → setWeight 100

What can break

• No pause and no analysis (just a slow RollingUpdate).

How to read this chapter

Steps, promote/abort/inspect.