kubernetes-patterns

name	kubernetes-patterns
description	Use when deploying to Kubernetes, writing manifests, or designing K8s architecture. Covers Deployments, Services, Ingress, HPA autoscaling, RBAC, network policies, security contexts, resource limits, and Helm chart patterns.
user-invocable	false
allowed-tools	["Read","Write","Bash","Grep"]

Kubernetes Patterns

Deployment Patterns

Production-Ready Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
  labels:
    app: web-app
    version: v1.2.0
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 1
      maxSurge: 1
  selector:
    matchLabels:
      app: web-app
  template:
    metadata:
      labels:
        app: web-app
        version: v1.2.0
    spec:
      securityContext:
        runAsNonRoot: true
        runAsUser: 1000
        fsGroup: 2000
      containers:
        - name: web-app
          image: registry.example.com/web-app:v1.2.0
          ports:
            - containerPort: 8080
          resources:
            requests:
              cpu: 100m
              memory: 128Mi
            limits:
              cpu: 500m
              memory: 512Mi
          livenessProbe:
            httpGet:
              path: /healthz
              port: 8080
            initialDelaySeconds: 15
            periodSeconds: 20
          readinessProbe:
            httpGet:
              path: /ready
              port: 8080
            initialDelaySeconds: 5
            periodSeconds: 10
          env:
            - name: DATABASE_URL
              valueFrom:
                secretKeyRef:
                  name: db-credentials
                  key: url
      topologySpreadConstraints:
        - maxSkew: 1
          topologyKey: topology.kubernetes.io/zone
          whenUnsatisfiable: DoNotSchedule
          labelSelector:
            matchLabels:
              app: web-app

HorizontalPodAutoscaler

apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: web-app-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: web-app
  minReplicas: 3
  maxReplicas: 20
  metrics:
    - type: Resource
      resource:
        name: cpu
        target:
          type: Utilization
          averageUtilization: 70
    - type: Resource
      resource:
        name: memory
        target:
          type: Utilization
          averageUtilization: 80
  behavior:
    scaleUp:
      stabilizationWindowSeconds: 60
      policies:
        - type: Pods
          value: 2
          periodSeconds: 60
    scaleDown:
       

Network Policy

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: web-app-netpol
spec:
  podSelector:
    matchLabels:
      app: web-app
  policyTypes:
    - Ingress
    - Egress
  ingress:
    - from:
        - podSelector:
            matchLabels:
              app: ingress-nginx
      ports:
        - port: 8080
  egress:
    - to:
        - podSelector:
            matchLabels:
              app: database
      ports:
        - port: 5432
    - to:  # DNS
        - namespaceSelector: {}
      ports:
        - port: 53
          protocol: UDP

Best Practices

1. Resource limits — Set both requests and limits for every container
2. Health checks — Configure liveness, readiness, and startup probes
3. Pod disruption budgets — Protect availability during maintenance
4. Network policies — Default deny, then explicitly allow
5. RBAC — Minimal permissions, namespace-scoped roles
6. Secrets — Use external secrets operators (AWS Secrets Manager, Vault)
7. Labels — Standard labels: app, version, environment, team, component
8. Topology spread — Distribute pods across zones
9. Security context — RunAsNonRoot, read-only filesystem, drop capabilities
10. Resource quotas — Limit namespace resource consumption

Helm Chart Structure

charts/web-app/
├── Chart.yaml
├── values.yaml
├── values-production.yaml
├── templates/
│   ├── deployment.yaml
│   ├── service.yaml
│   ├── ingress.yaml
│   ├── hpa.yaml
│   ├── pdb.yaml
│   ├── networkpolicy.yaml
│   └── _helpers.tpl
└── tests/