Rolling Update

ELI5 — The Vibe Check

A Rolling Update is when you update your app one server at a time instead of all at once. While you're updating server 1, servers 2 and 3 still serve traffic normally. When server 1 is done, you move to server 2, then 3. Users never see downtime because there are always healthy servers running.

Real Talk

A rolling update is a deployment strategy that gradually replaces old instances with new ones, maintaining service availability throughout. Kubernetes rolling updates take down old pods one at a time while bringing up new ones, using readiness probes to ensure new pods are ready before taking down old ones.

Show Me The Code

# Kubernetes rolling update strategy
strategy:
  type: RollingUpdate
  rollingUpdate:
    maxUnavailable: 1
    maxSurge: 1

When You'll Hear This

"A rolling update means zero downtime deployments with automatic health checking." / "The rolling update stalled because the new pods kept failing the readiness check."