k8s部署微服务项目实战--react前端+springboot/python后端-第四节 前端项目部署总结以及引入ingress解决两个问题

通过前面两节的学习，我们已经可以将一个简单的react项目部署到k8s中，总结起来其实就是下面的几步：

1. 创建react项目

2. 打包生成build文件夹(或者其他命名的文件夹)

3. 上传到服务器中(只要是安装了docker的linux服务器都可以，推荐上传到k8s的master节点中)

4. 准备Dockerfile和nginx.conf文件

5. docker build生成image并且同步到其他节点中(或者上传到本地或远程仓库中)

6. 准备部署文件即yaml文件，通常包括deployment.yaml和service.yaml

7. 运行kubectl apply -f xxx.yaml即可。

 

但同时我们提出了两个问题：

第一：大部分的前端访问应该是通过域名的形式访问，即http://domainName/webgui/smartocr/index.html来访问。

第二：前端微服务需要访问后端微服务，如果是通过nodeIP+nodePort的方式访问也没有问题，但是，如果是按照serviceName:servicePort的方式访问(而此种方式正是微服务部署所提倡的)，当前的解决方案一定是访问不通的。

第一个问题好理解，就是要使用域名访问，跟我们访问www.baidu.com之类的是一个道理；第二个问题稍微有点不好理解，为什么通过nodeIP+nodePort的方式访问没有问题而通过serviceName:servicePort的方式访问就不行了呢？这是因为我们在前端发送类似于http://basemanage-be:8000/smartocr/BaseManage/cases这种serviceName+servicePort的方式调用后端微服务，实际上这个url是浏览器发出来的，而浏览器发出来的这个url是通过这个浏览器所在的本机上的dns来解析的，毫无疑问这肯定时解析不了的，因此请求无法发送给后端微服务。而通过nodeIP+nodePort的方式不需要通过本机的dns解析，因此没有问题。

 

好了，问题清楚了，那为什么可以通过在k8s中配置ingress来解决呢？

首先，ingress本身就可以解决需要对外暴露的微服务的域名访问问题，通过设置host和hostPath，我们的前端可以使用域名访问。

其次，对于处理前端请求的这个后端微服务，我们可以将其设置为另一个host和hostPath，这样所有前端发给后端的请求就类似于http://backend.com/smartocr/BaseManage/cases, 因为配置了ingress,因此该请求会被ingress处理，继而找到对应的后端服务进行处理。

OK，话不多说，看看怎么配置ingress，网上配置ingress的文章很多，总结下来就是先创建ingress controller，然后创建ingress rule：

首先创建ingress controller，这里使用的是nginx-ingress，这个mandatory.yaml文件我是从网上找的，不需要任何改动，拿过去直接就能用:

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 "<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: 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:
      hostNetwork: true
      nodeSelector:
        nginx: "nginx"
      # 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: quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.30.0
          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 -> 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

其次是创建ingress rule，需要注意的一点是Ingress rule的命名空间一定要和你的微服务的命名空间相同，负责它找不到你的微服务:

ingress_rule.yaml

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ingress-myapp
  annotations:
    kubernetes.io/ingress.class: "nginx"
    nginx.ingress.kubernetes.io/use-regex: "true"
    nginx.ingress.kubernetes.io/ssl-redirect: "false"
spec:
  rules:
  - host: smartocr.com
    http:
      paths:
      - path: /webgui/smartocr/
        backend:
          serviceName: service-basemanage
          servicePort: 7070
  - host: backend.com
    http:
      paths:
      - path: /smartocr/BaseManage/
        backend:
          serviceName: service-basemanage-be
          servicePort: 5555

注意看标红的host: backend.com，这就是处理前端请求的后端微服务service-basemanage-be的域名，所以后续你看到的url应该是类似于下图：

 访问成功，说明前端的请求正确发送到了后端。

至此，前端部署完全结束。