This guide is focused entirely on the most commonly used Kubernetes YAML examples and why you’d use them in a production or staging environment. These YAML definitions act as the foundation for automating, scaling, and managing containerized workloads.

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1. Pod YAML (Basic Unit of Execution)

Use this when you want to run a single container on the cluster.

apiVersion: v1
kind: Pod
metadata:
  name: simple-pod
spec:
  containers:
  - name: nginx
    image: nginx

This is the most basic unit in Kubernetes. Ideal for testing and debugging.

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2. Deployment YAML (For Scaling and Updates)

Use deployments to manage stateless apps with rolling updates and replicas.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
      - name: nginx
        image: nginx:1.21

---

3. Production-Ready Deployment Example

Use this to deploy a resilient application with health checks and resource limits.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: production-app
  labels:
    app: myapp
spec:
  replicas: 4
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp-container
        image: myorg/myapp:2.1.0
        ports:
        - containerPort: 80
        livenessProbe:
          httpGet:
            path: /healthz
            port: 80
          initialDelaySeconds: 15
          periodSeconds: 20
        readinessProbe:
          httpGet:
            path: /ready
            port: 80
          initialDelaySeconds: 5
          periodSeconds: 10
        resources:
          requests:
            cpu: "250m"
            memory: "512Mi"
          limits:
            cpu: "500m"
            memory: "1Gi"

---

4. Service YAML (Stable Networking Access)

apiVersion: v1
kind: Service
metadata:
  name: web-service
spec:
  selector:
    app: web
  ports:
  - port: 80
    targetPort: 80
  type: ClusterIP

---

5. ConfigMap YAML (External Configuration)

apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
data:
  LOG_LEVEL: "debug"
  FEATURE_FLAG: "true"

---

6. Secret YAML (Sensitive Information)

apiVersion: v1
kind: Secret
metadata:
  name: app-secret
stringData:
  password: supersecret123

---

7. PersistentVolumeClaim YAML (For Storage)

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: app-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi

---

8. Job YAML (Run Once Tasks)

apiVersion: batch/v1
kind: Job
metadata:
  name: hello-job
spec:
  template:
    spec:
      containers:
      - name: hello
        image: busybox
        command: ["echo", "Hello World"]
      restartPolicy: Never

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9. CronJob YAML (Recurring Tasks)

apiVersion: batch/v1
kind: CronJob
metadata:
  name: scheduled-task
spec:
  schedule: "*/5 * * * *"
  jobTemplate:
    spec:
      template:
        spec:
          containers:
          - name: task
            image: busybox
            args: ["/bin/sh", "-c", "echo Scheduled Job"]
          restartPolicy: OnFailure

---

10. Ingress YAML (Routing External Traffic)

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: web-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - host: myapp.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: web-service
            port:
              number: 80

---

11. NetworkPolicy YAML (Security Control)

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-nginx
spec:
  podSelector:
    matchLabels:
      app: nginx
  policyTypes:
  - Ingress
  ingress:
  - from:
    - podSelector:
        matchLabels:
          app: frontend