# 03 - Kubernetes Operators: CRD, Controller Pattern and Operator SDK in Practice

Operators encode operational knowledge as Kubernetes-native software. Learn how to build an Operator with Kubebuilder, design CRDs with OpenAPI schema, and implement the reconcile loop for managing PostgreSQL clusters.

## What you'll learn

- Cos'e un Kubernetes Operator e quando ha senso costruirne uno
- Custom Resource Definition (CRD): schema, versioning, validation
- Il Controller Pattern e il Reconcile Loop
- Operator SDK vs Kubebuilder: differenze e quando usare quale
- Implementare un Operator completo con Kubebuilder

*This article is part of the **Kubernetes Avanzato** series on federicocalo.dev.*

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## Read the full article

The complete article (20 min read) with code examples, diagrams, and practical exercises is available here:

**➡️ [03 - Kubernetes Operators: CRD, Controller Pattern and Operator SDK in Practice](https://federicocalo.dev/en/blog/kubernetes-operators-crd-controller-pattern-operator-sdk-en)**

`https://federicocalo.dev/en/blog/kubernetes-operators-crd-controller-pattern-operator-sdk-en`

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*By [Federico Calò](https://federicocalo.dev) — Software Developer & Technical Writer*