Kubernetes Operators

Custom controllers pro automatizaci aplikačního lifecycle v Kubernetes.

Co je Operator?

Operator = custom controller + CRD (Custom Resource Definition). Automatizuje operational knowledge — backup, scaling, failover.

CRD příklad

apiVersion: apiextensions.k8s.io/v1
kind: CustomResourceDefinition
metadata:
  name: databases.myapp.io
spec:
  group: myapp.io
  names: {kind: Database, plural: databases}
  scope: Namespaced
  versions:
    - name: v1
      served: true
      storage: true
      schema:
        openAPIV3Schema:
          type: object
          properties:
            spec:
              type: object
              properties:
                engine: {type: string}
                version: {type: string}
                replicas: {type: integer}

Populární Operators

• Prometheus Operator — monitoring stack
• Strimzi — Kafka na K8s
• Zalando Postgres Operator — PostgreSQL HA

Shrnutí

Operators kodifikují operational knowledge. Používejte existující operators, vlastní pište jen pro specifické potřeby.