K8s Ingress 详解

文章目录

• [K8s Ingress 详解](#K8s Ingress 详解)
• • [Ingress 资源清单](#Ingress 资源清单)
  • [Ingress 基于URL 实现路由](#Ingress 基于URL 实现路由)
  • [Ingress 基于名称虚拟主机](#Ingress 基于名称虚拟主机)
  • [Ingress 实现HTTPS](#Ingress 实现HTTPS)
  • • [创建TLS 证书](#创建TLS 证书)
    • 创建Secrets
    • 配置ingress
  • [Ingress Rewrite](#Ingress Rewrite)
  • [Ingress 灰度发布](#Ingress 灰度发布)
  • [Ingress 配置认证](#Ingress 配置认证)

K8s Ingress 详解

Ingress 资源清单

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata: 
  name: <string>
  namespace: <string>
spec:
  ingressClassName: "nginx"   # 适配的Ingress控制器
  rules: <[]Object>   #  Ingress 规则列表
  - host: <string>
    http: <Object>  
      paths: <[]Object>   # 虚拟主机PATH 定义列表，列表由path 和 backend 组成
      - path: <string>    # 匹配以什么开头，类似nginx 中的location的作用
        pathType: <string>  # Prefix 前缀匹配，不区分大小写 Exact 精确匹配URL， 区分大小写
        backend: <Object>   
          service: <Object>  # 关联的后端Service
            name: <string>   # 后端Service 的名称
            port: <Object>   # 后端Service 端口的对象
              name: <string>  # 端口的名称
              number: <integr>  # 端口号

Ingress 基于URL 实现路由

注: 同一域名，不同的URL调度到不同的 Service

部署demoapp

apiVersion: apps/v1
kind: Deployment
metadata:
  name: app-prod
spec:
  replicas: 2
  selector:
    matchLabels:
      app: demoapp
  template:
    metadata:
      labels:
        app: demoapp
    spec:
      containers:
      - name: demo
        image: nginx:1.7.9
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 80

---
apiVersion: v1
kind: Service
metadata:
  name: app-svc
spec:
  type: ClusterIP
  selector:
    app: demoapp
  ports:
  - port: 80
    targetPort: 80

部署demo tomcat

apiVersion: apps/v1
kind: Deployment
metadata:
  name: tomcat-prod
spec:
  replicas: 2
  selector:
    matchLabels:
      app: tomcat
  template:
    metadata:
      labels:
        app: tomcat
    spec:
      containers:
      - name: java
        image: tomcat:9.0.6
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: tomcat-svc
spec:
  type: ClusterIP
  selector:
    app: tomcat
  ports:
  - port: 8080
    targetPort: 8080

部署ingress

• 默认URL：用户请求foo.ingress.net/app，代理到后端请求也会带上/app，后端无法处理该UrL，就会报错
• 修改URL：用户请求foo.ingress.net/app，代理到后端后，将请求的/app删除，foo.ingress,net/

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: foo-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /$2  # 配置Rewrite规则
spec:
  ingressClassName: "nginx"
  rules:
  - host: foo.ingress.net
    http:
      paths:
      - path: /app(/|$)(.*)  # 匹配的URL的第二部分（由第二个括号捕获的部分）作为新的目标路径。
        pathType: Prefix
        backend:
          service:
            name: app-svc
            port:
              number: 80
      - path: /java(/|$)(.*)
        pathType: Prefix
        backend:
          service:
            name: tomcat-svc
            port:
              number: 8080

Ingress 基于名称虚拟主机

配置Ingress

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: foo-ingress
spec:
  ingressClassName: "nginx"
  rules:
  - host: app.ingress.net
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: app-svc
            port:
              number: 80
  - host: java.ingress.net
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: tomcat-svc
            port:
              number: 8080

Ingress 实现HTTPS

在 Ingress 中引入 Secret 资源，然后告诉 Ingress 控制器使用 TLS 加密从客户端到负载均衡器的通道

创建TLS 证书

 # 使用openssl命令充当CA权威机构创建证书（生产不使用此方式生成证书，不被互联网认可的黑户证书）
openssl需要下载
[root@web01 ssl_key]# openssl genrsa -idea -out server.key 2048
Enter pass phrase for server.key: 123456
Verifying - Enter pass phrase for server.key: 123456
 
[root@web01 ssl_key]# ll
total 4
-rw-r--r--. 1 root root 1739 Dec  9 11:27 server.key

#生成自签证书(公钥)，同时去掉私钥的密码
[root@web01 ssl_key]# openssl req -days 36500 -x509 -sha256 -nodes -newkey rsa:2048 -keyout server.key -out server.crt
Country Name (2 letter code) [XX]:CN
State or Province Name (full name) []:meiguo
Locality Name (eg, city) [Default City]:riben
Organization Name (eg, company) [Default Company Ltd]:heishoudang
Organizational Unit Name (eg, section) []:oldboy
Common Name (eg, your name or your server's hostname) []:oldboy
Email Address []:123@qq.com

创建Secrets

[root@k8s-master ssl]# kubectl create secret tls java-ingress-tls --key=server.key --cert=server.crt 
secret/java-ingress-tls created

配置ingress

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: java-ingress
spec:
  ingressClassName: "nginx"

# https
  tls:
  - hosts: 
    - java.ingress.net
    secretName: "java-ingress-tls"

  rules:
  - host: java.oldxu.net
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: tomcat-svc
            port:
              number: 8080

Ingress Rewrite

• Ingress Rewrite：Rancher（一个流行的Kubernetes管理平台）中提供的一项功能，通过改写HTTP请求和响应的URL路径，实现请求重定向、负载均衡以及URL路径的重写。
• 请求重定向：可以将请求导向到不同的后端服务，实现简单的负载均衡。
• URL路径重写：修改请求的URL路径，使其匹配实际需要的后端服务。

上面基于URL实现路由方案中，就应用到了 ingress rewrite 方案，下面示例插入自定义的 Nginx 配置。

apiVersion: networking.k8s.io/v1  
kind: Ingress  
metadata:  
  name: my-app-ingress  
  annotations:  
    nginx.ingress.kubernetes.io/rewrite-target: /$2  # 如果需要基于路径重写，可以使用这个注解，但这里仅作为示例  
    nginx.ingress.kubernetes.io/configuration-snippet: |  
      location /old-path/ {  
          rewrite ^/old-path/(.*)$ /new-path/$1 break;  
          proxy_pass http://my-app-service;  
      }  
spec:  
  rules:  
  - http:  
      paths:  
      - path: /  
        pathType: Prefix  
        backend:  
          service:  
            name: my-app-service  
            port:  
              number: 80

Ingress 灰度发布

Ingress 灰度发布就是通过两套ingress 配置同一个域名，来实现

Ingress 灰度发布可以通过三个方式实现，

1. 基于Request Header的流量切分

   • 使用nginx.ingress.kubernetes.io/canary-by-header和nginx.ingress.kubernetes.io/canary-by-header-value annotations。
   • 客户端请求时，根据Request Header的值决定是否将请求路由到灰度版本。

2. 基于Cookie的流量切分

   • 使用nginx.ingress.kubernetes.io/canary-by-cookie annotation。
   • 根据客户端Cookie的值来决定是否将请求路由到灰度版本。

3. 基于服务权重的流量切分

   • 使用nginx.ingress.kubernetes.io/canary-weight annotation。
   • 设定灰度版本的权重（0-100%），按权重比例将请求路由到灰度版本。

4. 流量切分的优先级 header 和 cookie > 权重

生产版本

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: demoapp-ingress-prod
spec:
  ingressClassName: "nginx"
  rules:
  - host: "demoapp.ingress.net"
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: demoapp-prod-svc
            port:
              number: 80

灰度版本

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: demoapp-ingress-canary
  annotations:
    nginx.ingress.kubernetes.io/canary: "true"                  # 启动灰度发布
    #nginx.ingress.kubernetes.io/canary-by-header: "deploy"    # 基于header
    #nginx.ingress.kubernetes.io/canary-by-header-value: "new"
    #nginx.ingress.kubernetes.io/canary-weight: "30"    # 权重 30%流量调度到这个灰度的版本上
    nginx.ingress.kubernetes.io/canary-by-cookie: "request_from_wh"  # cookie
spec:
  ingressClassName: "nginx"
  rules:
  - host: "demoapp.ingress.net"
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: demoapp-canary-svc
            port:
              number: 80

Ingress 配置认证

先生成一个 basic-auth secret ，再引入nginx 就能给 nginx 设置账户密码

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: java-ingress
  annotations:
    nginx.ingress.kubernetes.io/auth-type: basic  # 认证类型
    nginx.ingress.kubernetes.io/auth-secret: basic-auth  # 包含用户和密码的 secret 资源名称
    nginx.ingress.kubernetes.io/auth-realm: 'Please User password'  # 要显示的信息
    nginx.ingress.kubernetes.io/rewrite-target: /$2
    nginx.ingress.kubernetes.io/configuration-snippet: |        # 自定义跳转规则
      rewrite ^/docs/(.*)$  /java/docs/$1 redirect;
      rewrite ^/manager/(.*)$  /java/manager/$1 redirect;
      rewrite ^/examples/(.*)$  /java/examples/$1 redirect;
    nginx.ingress.kubernetes.io/server-snippet: |
          set $agentflag 0;
          if ($http_user_agent ~* "(iPhone|android)" ){
                set $agentflag 1;
          }
          if ( $agentflag = 1 ) {
                return 301 http://app.ingress.net;
          }

spec:
  ingressClassName: "nginx"
  rules:
  - host: java.ingress.net
    http:
      paths:
      - path: /java(/|$)(.*)
        pathType: Prefix
        backend:
          service:
            name: tomcat-svc
            port:
              number: 8080