Service 与 Ingress

概述

服务暴露、Ingress 配置、TLS 终止等技能。

Service 类型

ClusterIP（默认）

apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  type: ClusterIP
  selector:
    app: nginx
  ports:
  - port: 80
    targetPort: 8080

NodePort

apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  type: NodePort
  selector:
    app: nginx
  ports:
  - port: 80
    targetPort: 8080
    nodePort: 30080      # 30000-32767

LoadBalancer

apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  type: LoadBalancer
  selector:
    app: nginx
  ports:
  - port: 80
    targetPort: 8080

ExternalName

apiVersion: v1
kind: Service
metadata:
  name: external-db
spec:
  type: ExternalName
  externalName: db.example.com

Headless Service

apiVersion: v1
kind: Service
metadata:
  name: headless-service
spec:
  clusterIP: None
  selector:
    app: nginx
  ports:
  - port: 80

Service 操作

# 查看 Service
kubectl get svc
kubectl get svc -o wide
kubectl describe svc service-name

# 创建 Service
kubectl expose deploy deployment-name --port=80 --target-port=8080
kubectl expose deploy deployment-name --type=NodePort --port=80

# 删除 Service
kubectl delete svc service-name

# 测试 Service
kubectl run test --rm -it --image=busybox -- wget -qO- http://service-name

Ingress 配置

基础 Ingress

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: my-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  ingressClassName: nginx
  rules:
  - host: example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: my-service
            port:
              number: 80

多路径 Ingress

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: multi-path-ingress
spec:
  ingressClassName: nginx
  rules:
  - host: example.com
    http:
      paths:
      - path: /api
        pathType: Prefix
        backend:
          service:
            name: api-service
            port:
              number: 80
      - path: /web
        pathType: Prefix
        backend:
          service:
            name: web-service
            port:
              number: 80

多域名 Ingress

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: multi-host-ingress
spec:
  ingressClassName: nginx
  rules:
  - host: api.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: api-service
            port:
              number: 80
  - host: web.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: web-service
            port:
              number: 80

TLS 配置

创建 TLS Secret

# 从证书文件创建
kubectl create secret tls tls-secret --cert=cert.pem --key=key.pem

# 查看 Secret
kubectl get secret tls-secret -o yaml

Ingress TLS

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: tls-ingress
  annotations:
    nginx.ingress.kubernetes.io/ssl-redirect: "true"
spec:
  ingressClassName: nginx
  tls:
  - hosts:
    - example.com
    secretName: tls-secret
  rules:
  - host: example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: my-service
            port:
              number: 80

cert-manager 自动证书

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

Ingress 注解

Nginx Ingress 常用注解

metadata:
  annotations:
    # 重写路径
    nginx.ingress.kubernetes.io/rewrite-target: /$2
    
    # SSL 重定向
    nginx.ingress.kubernetes.io/ssl-redirect: "true"
    
    # 代理超时
    nginx.ingress.kubernetes.io/proxy-connect-timeout: "30"
    nginx.ingress.kubernetes.io/proxy-read-timeout: "300"
    nginx.ingress.kubernetes.io/proxy-send-timeout: "300"
    
    # 请求体大小
    nginx.ingress.kubernetes.io/proxy-body-size: "50m"
    
    # 限流
    nginx.ingress.kubernetes.io/limit-rps: "10"
    
    # WebSocket
    nginx.ingress.kubernetes.io/proxy-http-version: "1.1"
    nginx.ingress.kubernetes.io/upstream-hash-by: "$request_uri"
    
    # 跨域
    nginx.ingress.kubernetes.io/enable-cors: "true"
    nginx.ingress.kubernetes.io/cors-allow-origin: "*"

Ingress 操作

# 查看 Ingress
kubectl get ingress
kubectl get ing -o wide
kubectl describe ing ingress-name

# 查看 Ingress Controller
kubectl get pods -n ingress-nginx
kubectl logs -n ingress-nginx -l app.kubernetes.io/name=ingress-nginx

# 测试 Ingress
curl -H "Host: example.com" http://ingress-ip/

常见场景

场景 1：路径重写

# /api/v1/users -> /users
metadata:
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
  rules:
  - host: example.com
    http:
      paths:
      - path: /api(/|$)(.*)
        pathType: Prefix
        backend:
          service:
            name: api-service
            port:
              number: 80

场景 2：会话保持

metadata:
  annotations:
    nginx.ingress.kubernetes.io/affinity: "cookie"
    nginx.ingress.kubernetes.io/session-cookie-name: "route"
    nginx.ingress.kubernetes.io/session-cookie-expires: "172800"

场景 3：基础认证

# 创建认证 Secret
htpasswd -c auth admin
kubectl create secret generic basic-auth --from-file=auth

metadata:
  annotations:
    nginx.ingress.kubernetes.io/auth-type: basic
    nginx.ingress.kubernetes.io/auth-secret: basic-auth
    nginx.ingress.kubernetes.io/auth-realm: "Authentication Required"

场景 4：调试 Service 连通性

# 检查 Endpoints
kubectl get endpoints service-name

# 测试 Pod 到 Service
kubectl run test --rm -it --image=busybox -- sh
wget -qO- http://service-name:port

# 检查 DNS
kubectl run test --rm -it --image=busybox -- nslookup service-name

故障排查

问题	排查方法
Service 无法访问	检查 Endpoints、Pod 标签
Ingress 404	检查路径配置、后端 Service
TLS 错误	检查证书 Secret、域名匹配
502 Bad Gateway	检查后端 Pod 状态、健康检查

# 检查 Service Endpoints
kubectl get endpoints service-name

# 检查 Ingress Controller 日志
kubectl logs -n ingress-nginx -l app.kubernetes.io/name=ingress-nginx --tail=100

# 测试后端连通性
kubectl port-forward svc/service-name 8080:80
curl localhost:8080