ingress-nginx 部署使用及原理简介

ingress：

可以简单理解为service的service，他通过独立的ingress对象来制定请求转发的规则，把请求路由到一个或多个service中。这样就把服务与请求规则解耦了，可以从业务维度统一考虑业务的暴露，而不用为每个service单独考虑。

举个例子，现在集群有api、文件存储、前端3个service，可以通过一个ingress对象来实现图中的请求转发。
ingress-nginx 部署使用及原理简介
ingress规则是很灵活的，可以根据不同域名、不同path转发请求到不同的service，并且支持https/http。

ingress与ingress-controller

ingress对象：指的是k8s中的一个api对象，一般用yaml配置。作用是定义请求如何转发到service的规则，可以理解为配置模板。
ingress-controller：具体实现反向代理及负载均衡的程序，对ingress定义的规则进行解析，根据配置的规则来实现请求转发。

ingress-controller才是负责具体转发的组件，通过各种方式将它暴露在集群入口，外部对集群的请求流量会先到ingress-controller，而ingress对象是用来告诉ingress-controller该如何转发请求，比如哪些域名哪些path要转发到哪些服务等等

ingress-controller

ingress-controller并不是k8s自带的组件，实际上ingress-controller只是一个统称，用户可以选择不同的ingress-controller实现，目前，由k8s维护的ingress-controller只有google云的GCE与ingress-nginx两个，其他还有很多第三方维护的ingress-controller。一般来说，ingress-controller的形式都是一个pod，里面跑着daemon程序和反向代理程序。daemon负责不断监控集群的变化，根据ingress对象生成配置并应用新配置到反向代理，比如nginx-ingress就是动态生成nginx配置，动态更新upstream，并在需要的时候reload程序应用新配置。

ingress

ingress是一个API对象，和其他对象一样，通过yaml文件来配置。ingress通过http或https暴露集群内部service，给service提供外部URL、负载均衡、SSL/TLS能力以及基于host的方向代理。ingress要依靠ingress-controller来具体实现以上功能。

ngress-nginx解决了生产环境中哪些问题？

1）动态配置服务：
如果按照传统方式，当新增加一个服务时，我们可能需要在流量入口加一个反向代理指向我们新的服务，而使用ingress，只需要配置好ingress，当服务启动时，会自动注册到ingress当中，不需要额外的操作。

2）减少不必要的Port暴露（安全，端口容易管理）
我们知道部署k8s时，是需要关闭防火墙的，主要原因是k8s的很多服务会以nodeport方式映射出去，这样对于宿主机来说是非常的不安全的，而ingress可以避免这个问题，只需要将ingress自身服务映射出去，就可代理后端所有的服务，则后端服务不需要映射出去

部署ingress-nginx

1、配置ingress-nginx yaml部署文件

vim 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: apps/v1
kind: Deployment
metadata:
  name: default-http-backend
  labels:
    app: default-http-backend
  namespace: ingress-nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: default-http-backend
  template:
    metadata:
      labels:
       app: default-http-backend
    spec:
      terminationGracePeriodSeconds: 60
      containers:
      - name: default-http-backend
        image:  registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64:1.5      #建议提前在node节点下载镜像；
        livenessProbe:
          httpGet:
            path: /healthz
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 30
          timeoutSeconds: 5
        ports:
        - containerPort: 8080
        resources:
         # 这里调整了cpu和memory的大小，可能不同集群限制的最小值不同，看部署失败的原因就清楚
          limits:
            cpu: 100m
            memory: 100Mi
          requests:
            cpu: 100m
            memory: 100Mi
---
apiVersion: v1
kind: Service
metadata:
  name: default-http-backend
  # namespace: ingress-nginx
  namespace: ingress-nginx
  labels:
    app: default-http-backend
spec:
  ports:
  - port: 80
    targetPort: 8080
  selector:
    app: default-http-backend
---
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 "<election-id>-<ingress-class>"
      # Here: "<ingress-controller-leader>-<nginx>"
      # 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: 2
  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:
      # wait up to five minutes for the drain of connections
      terminationGracePeriodSeconds: 300
      serviceAccountName: nginx-ingress-serviceaccount
      nodeSelector:
        kubernetes.io/os: linux
      containers:
        - name: nginx-ingress-controller
          image: suisrc/ingress-nginx:0.30.0   #建议提前在node节点下载镜像；
          args:
            - /nginx-ingress-controller
            - --default-backend-service=$(POD_NAMESPACE)/default-http-backend
            - --configmap=$(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 -> 101
            runAsUser: 101
          env:
            - name: POD_NAME
              valueFrom:
                fieldRef:
                  fieldPath: metadata.name
            - name: POD_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
          ports:
            - name: http
              containerPort: 80
              protocol: TCP
            - name: https
              containerPort: 443
              protocol: TCP
          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
          lifecycle:
            preStop:
              exec:
                command:
                  - /wait-shutdown
---
apiVersion: v1
kind: LimitRange
metadata:
  name: ingress-nginx
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
spec:
  limits:
  - min:
      memory: 90Mi
      cpu: 100m
    type: Container
---
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
      # HTTP
      nodePort: 32080
    - name: https
      port: 443
      targetPort: 443
      protocol: TCP
     # HTTPS
      nodePort: 32443
  selector:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx

2、运行Yaml文件
kubectl apply -f mandatory.yaml

3、检查创建好的Ingress-nginx
kubectl get all --namespace ingress-nginx -o wide
ingress-nginx 部署使用及原理简介

4、访问ingress-nginx服务，查看是否配置成功
ingress-nginx 部署使用及原理简介
提示404，这个因为当前ingress-nginx服务现在还没有后端服务，这是正常的，到此Ingress控制器部署成功！！！

二、部署Tomcat后端服务来验证Ingress

1、创建tomcat部署文件

vim tomcat-deploy.yaml

apiVersion: v1
kind: Service
metadata:
  name: tomcat
  namespace: default     #使用默认的名称空间即可
spec:
  selector:
    app: tomcat
    release: canary
  ports:
  - name: http
    port: 8080
    targetPort: 8080
  - name: ajp
    port: 8009
    targetPort: 8009

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: tomcat-deploy
spec:
  replicas: 3
  selector:
    matchLabels:
      app: tomcat
      release: canary
  template:
    metadata:
      labels:
        app: tomcat
        release: canary
    spec:
      containers:
      - name: tomcat
        image: tomcat:7-alpine
        ports:
        - name: httpd
          containerPort: 8080
        - name: ajp
          containerPort: 8009

kubectl apply -f tomcat-deploy.yaml  #运行Yaml文件
kubectl get pod |grep tomcat-deploy #检查pod是否部署成功

将tomcat添加至ingress-nginx中

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ingress-tomcat
  namespace: default
  annotations:
    kubernets.io/ingress.class: "nginx"
spec:
  rules:
  - host: www.sunwenbo.com  #将域名与node IP 绑定写入访问节点hosts文件
    http:
      paths:
      - path:
        backend:
          serviceName: tomcat #service名称
          servicePort: 8080   #cluster 端口号
  - host: www.sunwenbo-nginx.com 
    http:
      paths:
      - path:
        backend:
          serviceName: nginx-deployment
          servicePort: 80

kubectl apply -f ingress-tomcat.yaml  #运行Yaml文件
kubectl get ingress   #检查生成的ingress信息

2.2、将域名解析写入访问节点hosts文件
ingress-nginx 部署使用及原理简介

2.3、验证tomcat服务
http://www.sunwenbo.com:32080

http://www.sunwenbo-nginx.com:32080

ingress-nginx 部署使用及原理简介

3、Https访问验证,创建私有证书及secret

openssl genrsa -out tls.key 2048  #执行成功后，该目录下会生成tls.key文件

openssl req -new -x509 -key tls.key -out tls.crt -subj /C=CN/ST=GD/L=SZ/O=FSI/CN=www.sunwenbo.com   #域名必须为提供服务的域名， 执行成功后，该目录下会生成
tls.crt文件
kubectl create secret tls tomcat-secret --cert=tls.crt --key=tls.key  #创建名称为tomcat-secret的secret文件
kubectl get secrets   #检查创建的secret文件：

3.2、将证书应用至tomcat服务中

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ingress-tomcat-tls
  namespace: default
  annotations:
    kubernets.io/ingress.class: "nginx"
spec:
  tls:
  - hosts:
    - www.sunwenbo.com        #与secret证书的域名需要保持一致
    secretName: tomcat-secret   #secret证书的名称
  rules:
  - host: www.sunwenbo.com
    http:
      paths:
      - path:
        backend:
          serviceName: tomcat
          servicePort: 8080

kubectl apply -f ingress-tomcat-tls.yaml   #运行该文件
kubectl get ingress  #检查生成的ingress信息

3.3、Https访问tomcat服务
https://www.sunwenbo.com:32443
ingress-nginx 部署使用及原理简介