引言

云原生架构是现代应用部署的标准模式。本文将深入探讨如何使用Kubernetes、服务网格和DevOps实践构建弹性、可扩展的云原生应用。

一、Kubernetes核心概念

1.1 Pod与Deployment

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# ========== Pod配置 ==========

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
  labels:
    app: nginx
spec:
  containers:
  - name: nginx
    image: nginx:1.25
    ports:
    - containerPort: 80
    resources:
      requests:
        memory: "64Mi"
        cpu: "250m"
      limits:
        memory: "128Mi"
        cpu: "500m"
    livenessProbe:
      httpGet:
        path: /
        port: 80
      initialDelaySeconds: 30
      periodSeconds: 10
    readinessProbe:
      httpGet:
        path: /
        port: 80
      initialDelaySeconds: 5
      periodSeconds: 5

---
# ========== Deployment配置 ==========

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.25
        ports:
        - containerPort: 80
        env:
        - name: ENVIRONMENT
          value: "production"
        volumeMounts:
        - name: config-volume
          mountPath: /etc/nginx/config.d
      volumes:
      - name: config-volume
        configMap:
          name: nginx-config

1.2 Service与Ingress

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# ========== Service配置 ==========

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

---
# ========== Ingress配置 ==========

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: nginx-ingress
  annotations:
    kubernetes.io/ingress.class: nginx
    cert-manager.io/cluster-issuer: letsencrypt-prod
    nginx.ingress.kubernetes.io/ssl-redirect: "true"
spec:
  tls:
  - hosts:
    - app.example.com
    secretName: app-tls
  rules:
  - host: app.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: nginx-service
            port:
              number: 80

二、服务网格

2.1 Istio配置

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# ========== Istio VirtualService ==========

apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
  - reviews
  http:
  - match:
    - headers:
        end-user:
          exact: jason
    fault:
      delay:
        percentage:
          value: 100
        fixedDelay: 3s
    route:
    - destination:
        host: reviews
        subset: v2
  - route:
    - destination:
        host: reviews
        subset: v1

---
# ========== Istio DestinationRule ==========

apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: reviews
  trafficPolicy:
    loadBalancer:
      simple: LEAST_CONN
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
    trafficPolicy:
      loadBalancer:
        simple: RANDOM

三、云原生最佳实践

3.1 健康检查

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livenessProbe:
  httpGet:
    path: /health/live
    port: 8080
  initialDelaySeconds: 30
  periodSeconds: 10
  timeoutSeconds: 5
  failureThreshold: 3

readinessProbe:
  httpGet:
    path: /health/ready
    port: 8080
  initialDelaySeconds: 5
  periodSeconds: 5
  timeoutSeconds: 3
  failureThreshold: 3

startupProbe:
  httpGet:
    path: /health/startup
    port: 8080
  initialDelaySeconds: 0
  periodSeconds: 5
  timeoutSeconds: 3
  failureThreshold: 30

3.2 资源限制

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resources:
  requests:
    memory: "256Mi"
    cpu: "250m"
  limits:
    memory: "512Mi"
    cpu: "500m"

总结

云原生架构是现代应用部署的最佳实践。通过Kubernetes、服务网格和DevOps的结合，可以构建弹性、可扩展的应用系统。

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