Kubernetes Patterns

Production-grade Kubernetes patterns for deploying, managing, and debugging workloads reliably.

When to Activate

• Writing Kubernetes manifests (Deployments, Services, Ingress, Jobs)
• Configuring resource requests/limits, liveness/readiness probes
• Setting up RBAC, namespaces, or ServiceAccounts
• Managing configuration and secrets in K8s
• Debugging CrashLoopBackOff, OOMKilled, pending pods, or image pull errors
• Configuring HPA (Horizontal Pod Autoscaler) or PodDisruptionBudgets
• Reviewing K8s YAML for security or correctness

When to Use

Same as When to Activate above. This alias satisfies repo skill-format conventions. Use this skill any time you are writing, reviewing, or debugging Kubernetes YAML and workloads.

How It Works

This skill provides copy-pasteable, production-grade YAML patterns and kubectl debugging commands organized by task:

1. Deployment template — A fully configured production Deployment with security context, rolling update strategy, all three probe types, resource limits, and environment injection from ConfigMap/Secret.
2. Probes — Decision table for startup vs liveness vs readiness, with correct failureThreshold × periodSeconds math.
3. Services & Ingress — ClusterIP, LoadBalancer, and TLS Ingress patterns with cert-manager annotations.
4. ConfigMaps & Secrets — envFrom, file-mount, and external secrets guidance.
5. Resource management — Requests vs limits rules of thumb by workload type (web API, JVM, worker, sidecar).
6. RBAC — Least-privilege ServiceAccount → Role → RoleBinding chain.
7. HPA & PDB — Autoscaling and node-drain safety configurations.
8. Jobs & CronJobs — One-off and scheduled workload patterns with correct restartPolicy.
9. kubectl cheatsheet — Logs, exec, rollback, port-forward, dry-run, and common error diagnosis commands.
10. Anti-patterns & checklist — What NOT to do, and a security/reliability/observability checklist.

Examples

See the sections below for complete, runnable examples. Quick references:

Core Workload Patterns

Deployment — Production Template

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
  namespace: my-namespace
  labels:
    app: my-app
    version: "1.0.0"
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1          # Allow 1 extra pod during update
      maxUnavailable: 0    # Never reduce below desired count
  template:
    metadata:
      labels:
        app: my-app
        version: "1.0.0"
    spec:
      # Security context at pod level
      securityContext:
        runAsNonRoot: true
        runAsUser: 1001
        fsGroup: 1001

      # Graceful shutdown
      terminationGracePeriodSeconds: 30

      containers:
        - name: my-app
          image: ghcr.io/org/my-app:1.0.0   # Never use :latest
          imagePullPolicy: IfNotPresent

          ports:
            - containerPort: 8080
              protocol: TCP

          # Resource requests AND limits are both required
          resources:
            requests:
              cpu: "100m"
              memory: "128Mi"
            limits:
              cpu: "500m"
              memory: "256Mi"

          # Container security context
          securityContext:
            allowPrivilegeEscalation: false
            readOnlyRootFilesystem: true
            capabilities:
              drop:
                - ALL

          # Probes (see Probes section below)
          startupProbe:
            httpGet:
              path: /health
              port: 8080
            failureThreshold: 30
            periodSeconds: 5
          livenessProbe:
            httpGet:
              path: /health
              port: 8080
            initialDelaySeconds: 0
            periodSeconds: 30
            failureThreshold: 3
          readinessProbe:
            httpGet:
              path: /ready
              port: 8080
            initialDelaySeconds: 5

…