kubernetes

kubernetes

Production Kubernetes orchestration: pod scheduling, service discovery, Helm release management, RBAC, and cluster hardening. Covers EKS / GKE / AKS plus on-prem k3s and kind for local dev.

Core Objects

# deployment.yaml — stateless app, horizontally scalable
apiVersion: apps/v1
kind: Deployment
metadata: { name: api, labels: { app: api } }
spec:
  replicas: 3
  selector: { matchLabels: { app: api } }
  template:
    metadata: { labels: { app: api } }
    spec:
      containers:
      - name: api
        image: ghcr.io/myorg/api:v1.2.3
        ports: [ { containerPort: 8080 } ]
        resources:
          requests: { cpu: "100m", memory: "256Mi" }
          limits:   { cpu: "500m", memory: "512Mi" }
        livenessProbe:
          httpGet: { path: /health, port: 8080 }
          initialDelaySeconds: 10
          periodSeconds: 15
        readinessProbe:
          httpGet: { path: /ready, port: 8080 }

Services and Ingress

apiVersion: v1
kind: Service
metadata: { name: api }
spec:
  selector: { app: api }
  ports: [ { port: 80, targetPort: 8080 } ]
  type: ClusterIP   # internal; use LoadBalancer for external
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: api
  annotations:
    cert-manager.io/cluster-issuer: letsencrypt
    nginx.ingress.kubernetes.io/rate-limit: "100"   # req/min per IP
spec:
  ingressClassName: nginx
  tls: [ { hosts: [api.example.com], secretName: api-tls } ]
  rules:
  - host: api.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend: { service: { name: api, port: { number: 80 } } }

Helm Chart Structure

Helm is the package manager. Chart templates parameterise everything per environment.

charts/api/
├── Chart.yaml
├── values.yaml          # defaults
├── values-prod.yaml     # override per env
└── templates/
    ├── deployment.yaml
    ├── service.yaml
    ├── ingress.yaml
    ├── hpa.yaml
    └── _helpers.tpl

# values.yaml
image:
  repository: ghcr.io/myorg/api
  tag: v1.2.3
replicas: 3
resources:
  requests: { cpu: 100m, memory: 256Mi }
  limits:   { cpu: 500m, memory: 512Mi }