Canary vs Blue-Green vs Preview Rollout Strategies

MD
R
Markdown

Explanation on the 2 web application rollout strategies

Default (basic)

There is only the latest version of the app deployed (always green)

Blue/Green (intermediate)

There are 2 versions of the app (green:latest and bue:previous). There is an immediate switchover by the orchestrator (eg. Helm) or a delayed switchover Traffic is routed to only 1 version of the app, either the latest or previous Kubernetes rollouts are blue green as pods termination and starting follows a controlled round-robin iteration pattern

Preview (pre-canary)

The latest green version of the app is available temporarily on a separate subdomain for UAT, E2E, Integration Tests before rolling out to application users. After this stage the app is deployed into canary mode

Canary (advanced)

The green version of the app (latest) is available only to a subset of users 20% All the remaining users will see the 80% This is usually adjusted on the Load Balancer level or Ingress Router.

Created on 8/20/2021