从0开始搞K8S:Ingress-nginx 实例

案例：

准备

准备两个的Deployment与对应的SVC

使用自建的pyapp镜像

app.py V4版本 之前还有V1 V2 V3 

from flask import Flask, request, jsonify
import socket

app = Flask(__name__)

version = "v4"

@app.route('/', methods=['GET'])
def stop_endpoint():
    name = request.args.get('name', None)  # 从 URL 查询字符串中获取 name 参数

    # 返回响应
    return jsonify({'version': version})

@app.route('/hostname', methods=['GET'])
def get_hostname():
    hostname = socket.gethostname()
    return jsonify({'version': version, 'hostname': hostname})

@app.errorhandler(404)
def page_not_found(e):
    url = request.path
    return jsonify({'version': version, 'url': url})


if __name__ == '__main__':
    app.run("0.0.0.0", debug=True)  # 在开发模式下运行 Flask 应用

dockerfile

FROM python
WORKDIR /app
RUN pip3 --no-cache-dir install -i https://mirrors.aliyun.com/pypi/simple/ flask
COPY app.py /app/app.py
EXPOSE 5000
ENTRYPOINT ["python3", "app.py"]

镜像

harbor.tangotz.com/pyapp/pyapp:v4

harbor.tangotz.com/pyapp/pyapp:v3

使用V3 V4两个镜像，创建两个deployment

deploy-v3.yml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: pyapp-v3-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: pyapp_v3
  template:
    metadata:
      labels:
        app: pyapp_v3
    spec:
      containers:
      - image: harbor.tangotz.com/pyapp/pyapp:v3
        name: pyapp-v3-pod
        ports:
        - containerPort: 5000
  

deploy-v4.yml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: pyapp-v4-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: pyapp_v4
  template:
    metadata:
      labels:
        app: pyapp_v4
    spec:
      containers:
      - image: harbor.tangotz.com/pyapp/pyapp:v4
        name: pyapp-v4-pod
        ports:
        - containerPort: 5000

创建对应的SVC

svc-v3.yml

apiVersion: v1
kind: Service
metadata:
  name: pyapp-v3-svc
spec:
  selector:
    app: pyapp_v3
  ports:
  - port: 8080
    targetPort: 5000

svc-v4.yml

apiVersion: v1
kind: Service
metadata:
  name: pyapp-v4-svc
spec:
  selector:
    app: pyapp_v4
  ports:
  - port: 8080
    targetPort: 5000

实现目标1

访问 v3.tangotz.com 转发到svc-v3上 

ingress-v3.yml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: pyapp-v3-ingress
spec:
  ingressClassName: nginx
  rules:
  - host: v3.tangotz.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
        service:
          name: pyapp-v3-svc
          port:
            number: 8080        

访问 v4.tangotz.com 转发到svc-v4上

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: pyapp-v4-ingress
spec:
  ingressClassName: nginx
  rules:
  - host: v4.tangotz.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
        service:
          name: pyapp-v4-svc
          port:
            number: 8080   

效果：

实现目标2 

访问 v.tangotz.com/v3 转发到svc-v3上

访问 v.tangotz.com/v4 转发到svc-v4上

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-v
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
  ingressClassName: nginx
  rules:
  - host: v.tangotz.com
    http:
      paths:
      - path: /v3(/|$)(.*)
        pathType: ImplementationSpecific
        backend:
          service:
            name: pyapp-v3-svc
            port:
              number: 8080
      - path: /v4(/|$)(.*)
        pathType: ImplementationSpecific
        backend:
          service:
            name: pyapp-v4-svc
            port:
              number: 8080

在写这个示例的时候，关于path正则遇到了一些小麻烦，这个示例的核心是根据url的开头是/v3 /v4来决定流量代理到那个svc上，并将请求重写，去掉/v3 /v4，直接访问后面的路径。

最初写的是/v3/(.*) ，匹配组相应的就是$1，但是这个写法不能匹配/v3或者/v4，因为单独的/v3 /v3是没有后面的是无法和path中的正则匹配，多了一个/ 

效果

实现目标3

https配置

创建tls secret

使用阿里云创建一个免费证书做演示

kubectl create secret tls ssl-tangotz --cert=./ssl.tangotz.com.pem --key=./ssl.tangotz.com.key

在资源文件中添加tls配置

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress-tls
spec:
  ingressClassName: nginx
  rules:
  - host: ssl.tangotz.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service: 
            name: pyapp-v4-svc
            port:
              number: 8080
  tls:
  - hosts：
    - ssl.tangotz.com
      secretName: ssl-tangotz

修改hosts文件用以实现访问

效果

注意：使用特殊方式上网时，注意检查浏览器代理情况，防止出现Hosts修改不生效的情况。