Kubernetes-11 K8s的Ingress

前言

如果我们想让外部可以访问Pod，需要通过SVC的NodePort模式暴露IP+端口号来实现。

• 在每个节点上都会启动端口
• 在访问的时候通过任何节点，通过IP+端口号就能实现

但NodePort还存在这一些缺陷

• 端口不能重复，所以每个端口只能用一次，一个端口对应一个应用
• 实际访问都是通过域名，根据不同域名跳转到不同端口服务中

Ingress和Pod的关系

Pod和Ingress是通过Service进行关联的，而Ingress作为统一入口，由Service管理一组Pod。

• 首先SVC通过label标签关联一组Pod
• 然后Ingress作为入口，首先需要关联到SVC，然后发现一组Pod
• 发现Pod以后，就可以做负载均衡

Ingress工作流程

在实际访问中，我们需要维护很多域名，a.com,b.com。然后不同的域名对应不同的SVC，然后SVC管理不同的Pod

注意：
Ingress不是内置组件，需要我们单独安装Ingress插件

部署使用Ingress

这里我们使用Ingress-Nignx

• 安装Ingress Controller
• 创建Ingress规则（通过标签发现）

首先创建一个Nginx的Deployment和SVC和Tomcat的Deployent和SVC

## nginx-deployment的yaml
cat dep-nginx.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
spec:
  selector:
    matchLabels:
      run: nginx
  replicas: 2
  template:
    metadata:
      labels:
        run: nginx
    spec:
      containers:
      - name: my-nginx
        image: nginx
        ports:
        - containerPort: 80
## tomcat的deployment的yaml
cat dep-tomcat.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: tomcat
spec:
  selector:
    matchLabels:
      run: tomcat
  replicas: 2
  template:
    metadata:
      labels:
        run: tomcat
    spec:
      containers:
      - name: tomcat
        image: tomcat
        ports:
        - containerPort: 8080
## nginx的svc
cat svc-nginx.yaml
apiVersion: v1
kind: Service
metadata:
  labels:
    app: web
  name: nginx
spec:
  ports:
  - port: 80
    name: web-nginx
  type: NodePort
  selector:
    run: nginx
## tomcat的svc
apiVersion: v1
kind: Service
metadata:
  labels:
    app: web
  name: tomcat
spec:
  ports:
  - port: 80
    name: web-tomcat
    targetPort: 8080
  type: NodePort
  selector:
    run: tomcat

引用yaml文件

kubectl apply -f dep-nginx.yaml dep-tomcat.yaml nginx-svc.yaml tomcat-svc.yaml
kubectl get svc,pod

kubectl get pod -o wide 
kubectl describe svc nginx
kubectl describe svc tomcat

可以看到已经部署成功了,并且SVC已经和Pod关联成功

部署Ingress-Nginx

##插件yaml
cat mandatory.yaml
apiVersion: v1
kind: Namespace
metadata:
  name: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---

kind: ConfigMap
apiVersion: v1
metadata:
  name: nginx-configuration
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---
kind: ConfigMap
apiVersion: v1
metadata:
  name: tcp-services
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---
kind: ConfigMap
apiVersion: v1
metadata:
  name: udp-services
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: nginx-ingress-serviceaccount
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
  name: nginx-ingress-clusterrole
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
rules:
  - apiGroups:
      - ""
    resources:
      - configmaps
      - endpoints
      - nodes
      - pods
      - secrets
    verbs:
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - nodes
    verbs:
      - get
  - apiGroups:
      - ""
    resources:
      - services
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - events
    verbs:
      - create
      - patch
  - apiGroups:
      - "extensions"
      - "networking.k8s.io"
    resources:
      - ingresses
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - "extensions"
      - "networking.k8s.io"
    resources:
      - ingresses/status
    verbs:
      - update

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: Role
metadata:
  name: nginx-ingress-role
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
rules:
  - apiGroups:
      - ""
    resources:
      - configmaps
      - pods
      - secrets
      - namespaces
    verbs:
      - get
  - apiGroups:
      - ""
    resources:
      - configmaps
    resourceNames:
      # Defaults to "-"
      # Here: "-"
      # This has to be adapted if you change either parameter
      # when launching the nginx-ingress-controller.
      - "ingress-controller-leader-nginx"
    verbs:
      - get
      - update
  - apiGroups:
      - ""
    resources:
      - configmaps
    verbs:
      - create
  - apiGroups:
      - ""
    resources:
      - endpoints
    verbs:
      - get

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: RoleBinding
metadata:
  name: nginx-ingress-role-nisa-binding
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: nginx-ingress-role
subjects:
  - kind: ServiceAccount
    name: nginx-ingress-serviceaccount
    namespace: ingress-nginx

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: nginx-ingress-clusterrole-nisa-binding
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: nginx-ingress-clusterrole
subjects:
  - kind: ServiceAccount
    name: nginx-ingress-serviceaccount
    namespace: ingress-nginx

---

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-ingress-controller
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app.kubernetes.io/name: ingress-nginx
      app.kubernetes.io/part-of: ingress-nginx
  template:
    metadata:
      labels:
        app.kubernetes.io/name: ingress-nginx
        app.kubernetes.io/part-of: ingress-nginx
      annotations:
        prometheus.io/port: "10254"
        prometheus.io/scrape: "true"
    spec:
      serviceAccountName: nginx-ingress-serviceaccount
      containers:
        - name: nginx-ingress-controller
          image: quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.25.0
          args:
            - /nginx-ingress-controller
            - --configmap=$(POD_NAMESPACE)/nginx-configuration
            - --tcp-services-configmap=$(POD_NAMESPACE)/tcp-services
            - --udp-services-configmap=$(POD_NAMESPACE)/udp-services
            - --publish-service=$(POD_NAMESPACE)/ingress-nginx
            - --annotations-prefix=nginx.ingress.kubernetes.io
          securityContext:
            allowPrivilegeEscalation: true
            capabilities:
              drop:
                - ALL
              add:
                - NET_BIND_SERVICE
            # www-data -> 33
            runAsUser: 33
          env:
            - name: POD_NAME
              valueFrom:
                fieldRef:
                  fieldPath: metadata.name
            - name: POD_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
          ports:
            - name: http
              containerPort: 80
            - name: https
              containerPort: 443
          livenessProbe:
            failureThreshold: 3
            httpGet:
              path: /healthz
              port: 10254
              scheme: HTTP
            initialDelaySeconds: 10
            periodSeconds: 10
            successThreshold: 1
            timeoutSeconds: 10
          readinessProbe:
            failureThreshold: 3
            httpGet:
              path: /healthz
              port: 10254
              scheme: HTTP
            periodSeconds: 10
            successThreshold: 1
            timeoutSeconds: 10

##SVC的yaml
cat service-nodeport.yaml
apiVersion: v1
kind: Service
metadata:
  name: ingress-nginx
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  type: NodePort
  ports:
    - name: http
      port: 80
      targetPort: 80
      protocol: TCP
    - name: https
      port: 443
      targetPort: 443
      protocol: TCP
  selector:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

部署Ingress，通过SVC名字关联

cat nginx-ingress.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: nginx-test
spec:
  rules:
    - host: www.a.com
      http:
        paths:
        - path: /
          backend:
            serviceName: nginx
            servicePort: 80
    - host: www.b.com
      http:
        paths:
        - path: /
          backend:
            serviceName: tomcat
            servicePort: 80

应用yaml文件，确认

kubectl apply -f mandatory.yaml service-nodeport.yaml nginx-ingress.yaml

kubectl get svc,deployment -n ingress-nginx
kubectl get ingress

在hosts文件加入解析的域名

www.a.com 192.168.2.73
www.b.com 192.168.2.73
在浏览器中访问
www.a.com:30891


到这里就完成了Ingress-Nginx的作用，通过域名+端口访问的方式。

Ingress HTTPS代理访问

创建证书，以及cert存储方式

openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -keyout tls.key -out tls.crt -subj "/CN=nginxsvc/O=nginxsvc"
kubectl create secret tls tls-secret --key tls.key --cert tls.crt

##配置Deployment、Service、Ingress

vim ingress.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata: 
  name: nginx-ingress
spec:
  tls:
    - hosts:
      - www.a.com
      secretName: tls-secret
    - hosts:
      - www.b.com
      secretName: tls-secret
  rules:
  - host: www.a.com
    http: 
      paths:
      - path: /
        backend:
          serviceName: web
          servicePort: 80
  - host: www.b.com
    http: 
      paths:
      - path: /
        backend:
          serviceName: tomcat
          servicePort: 80

应用yaml文件，访问443端口

kubectl apply -f ingress.yaml
kubectl get svc -n ingress-nginx

Nginx进行BasicAuth认证

##安装httpd软件包，创建认证文件，Secret

yum -y install httpd
htpasswd -c auth a.com
kubectl create secret generic basic-auth --from-file=auth

配置yaml文件

apiVersion: extensions/v1beta1
kind: Ingress
metadata: 
  name: nginx-ingress
  annotations:
    nginx.ingress.kubernetes.io/auth-type: basic
    nginx.ingress.kubernetes.io/auth-secret: basic-auth
    nginx.ingress.kubernetes.io/auth-realm: 'Authentication Required - a.com'
spec:
  tls:
    - hosts:
      - www.a.com
      secretName: tls-secret
    - hosts:
      - www.b.com
      secretName: tls-secret
  rules:
  - host: www.a.com
    http: 
      paths:
      - path: /
        backend:
          serviceName: web
          servicePort: 80
  - host: www.b.com
    http: 
      paths:
      - path: /
        backend:
          serviceName: tomcat
          servicePort: 80

应用ingress.yaml文件，测试访问

kubectl apply -f ingress.yaml

然后我们发现两个域名都需要认证了。配置成功！

Nginx重写

直接上yaml，我这里通过域名访问nginx的443端口，重写到后端tomcat的SVC的外部80端口，中间还实现了会话层卸载。

cat ingress.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata: 
  name: nginx-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: http://192.168.2.73:32550
spec:
  tls:
    - hosts:
      - www.a.com
      secretName: tls-secret
  rules:
  - host: www.a.com
    http: 
      paths:
      - path: /
        backend:
          serviceName: web
          servicePort: 80

kubectl apply -f ingress.yaml

下面还有一些功能，感兴趣的同学可以试一下

名称	描述	值
nginx.ingress.kubernetes.io/rewrite-target	必须重定向流量的目标URI	串
nginx.ingress.kubernetes.io/ssl-redirect	指示位置部分是否仅可访问SSL（当Ingress包含证书时默认为True）	布尔
nginx.ingress.kubernetes.io/force-ssl-redirect	即使Ingress未启用TLS，也强制重定向到HTTPS	布尔
nginx.ingress.kubernetes.io/app-root	定义Controller必须重定向的应用程序根，如果它在’/'上下文中	串
nginx.ingress.kubernetes.io/use-regex	指示Ingress上定义的路径是否使用正则表达式	布尔