Testing, Rollouts, and Canarying in Multi-CDN
Synopsis This chapter explains how changes to routing, configuration, and content are tested and deployed in a multi-CDN environment. It covers pre-production validation, cohort design, canary strategies, progressive exposure, measurement, guard rails, rollback, and record keeping. The goal is to make changes reversible, observable, and limited in blast radius. Purpose and scope Multi-CDN adds variables at several layers. DNS answers, proxy behavior, client logic, cache identity, and origin controls can all change outcomes. Testing must isolate causes and confirm improvements using indicators that reflect user experience. Rollouts must keep a safe default path and apply controls that prevent fast spread of harm. ...