Writing Kube Controllers for Everyone
summary
A practical recipe for real controllers: code is a main loop that pops meta namespace keys from a rate‑limited queue (commonly an exponential failure limiter), looks up objects via the shared informers cache and listers, deep copies before mutating, updates status and emits events. CronJob controller is ~400–1,000 lines and currently doesn’t use shared informers (a known flaw). Use ownerReferences for garbage collection, follow the 11 rules, and test with hundreds of table cases.
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chapters (16)
- 0:00Intro
- 0:55Controllers
- 3:25Where to start
- 6:15Queue
- 8:05Sheraton Format
- 10:40Event Handlers
- 13:40Main Loop
- 17:45Picture
- 18:45Closing Remarks
- 22:50Observed Generation
- 28:00Operator Framework
- 29:00Writing controllers in different languages
- 31:05Controllers in pods
- 34:45Notifications
- 35:20Leader Election
- 36:15Conformance Testing
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