Kubernetes Controller Development: Pitfalls and Best Practices

This article delves into the often-overlooked challenges of Kubernetes controller development. Drawing from real-world experiences, the author highlights common mistakes made by beginners, such as poorly designed CRDs, controllers with unclear responsibilities, and messy `Reconcile()` methods. The article stresses the importance of understanding Kubernetes API conventions, utilizing cached clients, handling work queues, and employing the expectations pattern. Real-world examples illustrate the consequences of these issues. The author concludes by recommending studying exemplary controller code and adhering to best practices for building reliable and scalable controllers.