Progressive Delivery

Progressive delivery is a modern software development lifecycle practice that builds upon continuous delivery. It aims to deploy updates in a controlled, gradual manner to limit the blast radius of potential failures.

Blue/Green Deployments

In a Blue/Green deployment, two identical environments exist (Blue and Green). At any time, only one environment is live and serving production traffic.

• Deploy: The new version is deployed to the inactive environment.
• Test: The new environment is tested thoroughly.
• Switch: Traffic is routed from the old environment to the new one seamlessly.
• Rollback: If issues occur, traffic can be instantly switched back to the old environment.

Canary Releases

Canary releases slowly roll out a change to a small subset of users before making it available to everyone.

• Phase 1: Route 5% of traffic to the new version.
• Monitor: Observe error rates, latency, and system health.
• Phase 2: If stable, increase traffic to 25%, 50%, and eventually 100%.

Tools like Argo Rollouts or Flagger natively support these strategies in Kubernetes environments.