Kubernetes 맛보기 — Pod·Deployment·Service·Ingress

# 가장 자주 보는 최소 예시 — Deployment + Service

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 3                    # Pod 3개 유지
  selector:
    matchLabels: { app: myapp }
  template:
    metadata: { labels: { app: myapp } }
    spec:
      containers:
        - name: web
          image: myapp:1.0
          ports: [{ containerPort: 3000 }]
          env:
            - name: DATABASE_URL
              valueFrom: { secretKeyRef: { name: db-secret, key: url } }
          resources:
            requests: { cpu: "100m", memory: "256Mi" }
            limits:   { cpu: "500m", memory: "512Mi" }
          readinessProbe:        # 준비됐는가?
            httpGet: { path: /healthz, port: 3000 }
          livenessProbe:         # 살아있는가?
            httpGet: { path: /healthz, port: 3000 }

---
apiVersion: v1
kind: Service
metadata: { name: myapp }
spec:
  selector: { app: myapp }
  ports: [{ port: 80, targetPort: 3000 }]
  type: ClusterIP