Design a CI/CD System: a system design question

Design a continuous integration and continuous delivery (CI/CD) system, the build and deploy question Meta and Google ask when they live in one giant repository. A shared queue and a shared machine will be abused by the first team that shows up with forty jobs. In this system design interview walkthrough, we size the build fleet, keep the queue fair, keep forked code away from production secrets, and make rollback mean the exact bytes you already shipped. You'll leave able to defend: • Fifty thousand builds a day on two hundred slots, with a fair queue per repository • A fast lane for hotfixes, capped near thirty percent so it cannot starve everyone else • Webhooks deduplicated on the delivery identifier, and build runners that are thrown away after every job • Forked code gets no production token, and tokens last about fifteen minutes • A cache keyed on the lockfile hash, and logs streamed in chunks so they outlive the runner • A canary of five percent on the same artifact, then promote or shift back to a named digest • One retry for a flaky test and quarantine near a five percent main-branch failure rate: blind retries cost about thirteen hundred hours a day Full 23 minute walkthrough, from requirements to the one-breath recap. Read the full lesson → https://yourally.live/academy/system-... Practice this under a clock → https://yourally.live YourAlly AI, the interview operating system. Sign up and start a live mock. Chapters: 0:00 Hook 0:49 Requirements 3:00 Definitions, triggers, and what a runner may see 5:28 Practice the fairness rule 6:13 The figures that size the fleet 9:06 Schedule, isolate, deploy the bytes you built 12:06 Walk a fork, then a hotfix 13:58 Warm pools, flakes, and the bytes 14:52 The instincts that fail this envelope 20:33 Five lines 21:36 Recap If this helped, subscribe for more Staff-level system design walkthroughs. #SystemDesign #CICD #DevOps #SystemDesignInterview #FAANGInterview #StaffEngineer #YourAlly