k8s新版本如何部署Ingress-nginx controller详细教程方法

小小编

3 年前

k8s 新版本部署 Ingress-nginx controller

本篇主要记录一下 k8s 新版本 1.23.5 中如何搭建 ingress controller 以及里面的注意项

新版本和老版本区别有不少，坑很多，只能从官网一点点撸

1.环境准备

操作系统：Centos7 （CentOS Linux release 7.9.2009）
Master 主节点： 1台虚拟机
Node 计算节点： 2台虚拟机
K8s version：v1.23.5 （选的较新的版本）
Docker version：20.10.14

环境和上一篇中 kubeadm 搭建 k8s 的一致

2.概述

下面从官网摘取的对于 Ingress 的介绍

2.1 什么是 Ingress

Ingress 是对集群中服务的外部访问进行管理的 API 对象，典型的访问方式是 HTTP。Ingress 可以提供负载均衡

Ingress 公开了从集群外部到集群内服务的 HTTP 和 HTTPS 路由。流量路由由 Ingress 资源上定义的规则控制。

下面是一个将所有流量都发送到同一 Service 的简单 Ingress 示例：

但是仅创建 Ingress 资源本身没有任何效果，需要有对应的 Ingress 控制器，你可能需要部署 Ingress 控制器，例如 ingress-nginx。你可以从许多 Ingress 控制器中进行选择。

2.2 什么是 Ingress controller

为了让 Ingress 资源工作，集群必须有一个正在运行的 Ingress 控制器。k8s官网维护了 3 个Ingress控制器

目前支持和维护 AWS、 GCE 和 Nginx Ingress 控制器，本篇就拿 Ingress-nginx 作为控制器为例讲解一下如何部署

还有一些社区等提供的控制器 |3.部署 Ingress-nginx controller本篇就拿最常用的 Ingress-nginx 作为 Ingress的控制器，实现k8s 把请求重定向到集群内部（Cluster Ip）服务去

3.1 deploy.yaml 坑点
Ingress-nginx 官网 https://kubernetes.github.io/ingress-nginx/ 提到了 deploy.yaml 文
Ingress-nginx 新版本的 depoly.yaml 有些不同，需要拉取下面2个镜像k8s.gcr.io/ingress-nginx/controller:v1.1.2k8s.gcr.io/ingress-nginx/kube-webhook-certgen:v1.1.1多半是下载不到的，所以需要自己替换一下，可以去docker hub 上找到对应的镜像文件

总结坑点：

新版本中提供了 IngressClass ，需要在编写 Ingress 的时候指定
Image 加载不到，需要手动去 docker hub 上找其他的并且修改 deploy.yaml文件

把 ingress-nginx-controller 使用 hostNetwork: true 进行部署比 NodePort 减少一层转发，但是需要指定选择打了标签的 node nodeSelector: app: ingress

3.2 deploy.yaml 样例（我自己修改后的可以参考）

#GENERATED FOR K8S 1.20
apiVersion: v1
kind: Namespace
metadata:
  labels:
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/name: ingress-nginx
  name: ingress-nginx
---
apiVersion: v1
automountServiceAccountToken: true
kind: ServiceAccount
metadata:
  labels:
    app.kubernetes.io/component: controller
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx
  namespace: ingress-nginx
---
apiVersion: v1
kind: ServiceAccount
metadata:
  annotations:
    helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgrade
    helm.sh/hook-delete-policy: before-hook-creation,hook-succeeded
  labels:
    app.kubernetes.io/component: admission-webhook
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx-admission
  namespace: ingress-nginx
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  labels:
    app.kubernetes.io/component: controller
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx
  namespace: ingress-nginx
rules:
  - apiGroups:
      - ""
    resources:
      - namespaces
    verbs:
      - get
  - apiGroups:
      - ""
    resources:
      - configmaps
      - pods
      - secrets
      - endpoints
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - services
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - networking.k8s.io
    resources:
      - ingresses
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - networking.k8s.io
    resources:
      - ingresses/status
    verbs:
      - update
  - apiGroups:
      - networking.k8s.io
    resources:
      - ingressclasses
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - ""
    resourceNames:
      - ingress-controller-leader
    resources:
      - configmaps
    verbs:
      - get
      - update
  - apiGroups:
      - ""
    resources:
      - configmaps
    verbs:
      - create
  - apiGroups:
      - ""
    resources:
      - events
    verbs:
      - create
      - patch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  annotations:
    helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgrade
    helm.sh/hook-delete-policy: before-hook-creation,hook-succeeded
  labels:
    app.kubernetes.io/component: admission-webhook
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx-admission
  namespace: ingress-nginx
rules:
  - apiGroups:
      - ""
    resources:
      - secrets
    verbs:
      - get
      - create
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  labels:
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx
rules:
  - apiGroups:
      - ""
    resources:
      - configmaps
      - endpoints
      - nodes
      - pods
      - secrets
      - namespaces
    verbs:
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - nodes
    verbs:
      - get
  - apiGroups:
      - ""
    resources:
      - services
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - networking.k8s.io
    resources:
      - ingresses
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - events
    verbs:
      - create
      - patch
  - apiGroups:
      - networking.k8s.io
    resources:
      - ingresses/status
    verbs:
      - update
  - apiGroups:
      - networking.k8s.io
    resources:
      - ingressclasses
    verbs:
      - get
      - list
      - watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  annotations:
    helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgrade
    helm.sh/hook-delete-policy: before-hook-creation,hook-succeeded
  labels:
    app.kubernetes.io/component: admission-webhook
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx-admission
rules:
  - apiGroups:
      - admissionregistration.k8s.io
    resources:
      - validatingwebhookconfigurations
    verbs:
      - get
      - update
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  labels:
    app.kubernetes.io/component: controller
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx
  namespace: ingress-nginx
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: ingress-nginx
subjects:
  - kind: ServiceAccount
    name: ingress-nginx
    namespace: ingress-nginx
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  annotations:
    helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgrade
    helm.sh/hook-delete-policy: before-hook-creation,hook-succeeded
  labels:
    app.kubernetes.io/component: admission-webhook
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx-admission
  namespace: ingress-nginx
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: ingress-nginx-admission
subjects:
  - kind: ServiceAccount
    name: ingress-nginx-admission
    namespace: ingress-nginx
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  labels:
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: ingress-nginx
subjects:
  - kind: ServiceAccount
    name: ingress-nginx
    namespace: ingress-nginx
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  annotations:
    helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgrade
    helm.sh/hook-delete-policy: before-hook-creation,hook-succeeded
  labels:
    app.kubernetes.io/component: admission-webhook
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx-admission
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: ingress-nginx-admission
subjects:
  - kind: ServiceAccount
    name: ingress-nginx-admission
    namespace: ingress-nginx
---
apiVersion: v1
data:
  allow-snippet-annotations: "true"
kind: ConfigMap
metadata:
  labels:
    app.kubernetes.io/component: controller
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx-controller
  namespace: ingress-nginx
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app.kubernetes.io/component: controller
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx-controller
  namespace: ingress-nginx
spec:
  externalTrafficPolicy: Local
  ipFamilies:
    - IPv4
  ipFamilyPolicy: SingleStack
  ports:
    - appProtocol: http
      name: http
      port: 80
      protocol: TCP
      targetPort: http
    - appProtocol: https
      name: https
      port: 443
      protocol: TCP
      targetPort: https
  selector:
    app.kubernetes.io/component: controller
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/name: ingress-nginx
  type: LoadBalancer
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app.kubernetes.io/component: controller
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx-controller-admission
  namespace: ingress-nginx
spec:
  ports:
    - appProtocol: https
      name: https-webhook
      port: 443
      targetPort: webhook
  selector:
    app.kubernetes.io/component: controller
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/name: ingress-nginx
  type: ClusterIP
---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app.kubernetes.io/component: controller
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx-controller
  namespace: ingress-nginx
spec:
  minReadySeconds: 0
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app.kubernetes.io/component: controller
      app.kubernetes.io/instance: ingress-nginx
      app.kubernetes.io/name: ingress-nginx
  template:
    metadata:
      labels:
        app.kubernetes.io/component: controller
        app.kubernetes.io/instance: ingress-nginx
        app.kubernetes.io/name: ingress-nginx
    spec:
      hostNetwork: true #修改  ingress-nginx-controller 为 hostNetwork模式 
      nodeSelector: #选择 node label 中有 app=ingress的节点进行部署
        app: ingress
      containers:
        - args:
            - /nginx-ingress-controller
            - --publish-service=$(POD_NAMESPACE)/ingress-nginx-controller
            - --election-id=ingress-controller-leader
            - --controller-class=k8s.io/ingress-nginx
            - --ingress-class=nginx
            - --configmap=$(POD_NAMESPACE)/ingress-nginx-controller
            - --validating-webhook=:8443
            - --validating-webhook-certificate=/usr/local/certificates/cert
            - --validating-webhook-key=/usr/local/certificates/key
          env:
            - name: POD_NAME
              valueFrom:
                fieldRef:
                  fieldPath: metadata.name
            - name: POD_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
            - name: LD_PRELOAD
              value: /usr/local/lib/libmimalloc.so
          image: k8s.gcr.io/ingress-nginx/controller:v1.1.2 #修改镜像地址
          imagePullPolicy: IfNotPresent
          lifecycle:
            preStop:
              exec:
                command:
                  - /wait-shutdown
          livenessProbe:
            failureThreshold: 5
            httpGet:
              path: /healthz
              port: 10254
              scheme: HTTP
            initialDelaySeconds: 10
            periodSeconds: 10
            successThreshold: 1
            timeoutSeconds: 1
          name: controller
          ports:
            - containerPort: 80
              name: http
              protocol: TCP
            - containerPort: 443
              name: https
              protocol: TCP
            - containerPort: 8443
              name: webhook
              protocol: TCP
          readinessProbe:
            failureThreshold: 3
            httpGet:
              path: /healthz
              port: 10254
              scheme: HTTP
            initialDelaySeconds: 10
            periodSeconds: 10
            successThreshold: 1
            timeoutSeconds: 1
          resources:
            requests:
              cpu: 100m
              memory: 90Mi
          securityContext:
            allowPrivilegeEscalation: true
            capabilities:
              add:
                - NET_BIND_SERVICE
              drop:
                - ALL
            runAsUser: 101
          volumeMounts:
            - mountPath: /usr/local/certificates/
              name: webhook-cert
              readOnly: true
      dnsPolicy: ClusterFirst
      nodeSelector:
        kubernetes.io/os: linux
      serviceAccountName: ingress-nginx
      terminationGracePeriodSeconds: 300
      volumes:
        - name: webhook-cert
          secret:
            secretName: ingress-nginx-admission
---
apiVersion: batch/v1
kind: Job
metadata:
  annotations:
    helm.sh/hook: pre-install,pre-upgrade
    helm.sh/hook-delete-policy: before-hook-creation,hook-succeeded
  labels:
    app.kubernetes.io/component: admission-webhook
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx-admission-create
  namespace: ingress-nginx
spec:
  template:
    metadata:
      labels:
        app.kubernetes.io/component: admission-webhook
        app.kubernetes.io/instance: ingress-nginx
        app.kubernetes.io/managed-by: Helm
        app.kubernetes.io/name: ingress-nginx
        app.kubernetes.io/part-of: ingress-nginx
        app.kubernetes.io/version: 1.1.2
        helm.sh/chart: ingress-nginx-4.0.18
      name: ingress-nginx-admission-create
    spec:
      containers:
        - args:
            - create
            - --host=ingress-nginx-controller-admission,ingress-nginx-controller-admission.$(POD_NAMESPACE).svc
            - --namespace=$(POD_NAMESPACE)
            - --secret-name=ingress-nginx-admission
          env:
            - name: POD_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
          image: k8s.gcr.io/ingress-nginx/kube-webhook-certgen:v1.1.1 #修改镜像地址
          imagePullPolicy: IfNotPresent
          name: create
          securityContext:
            allowPrivilegeEscalation: false
      nodeSelector:
        kubernetes.io/os: linux
      restartPolicy: OnFailure
      securityContext:
        fsGroup: 2000
        runAsNonRoot: true
        runAsUser: 2000
      serviceAccountName: ingress-nginx-admission
---
apiVersion: batch/v1
kind: Job
metadata:
  annotations:
    helm.sh/hook: post-install,post-upgrade
    helm.sh/hook-delete-policy: before-hook-creation,hook-succeeded
  labels:
    app.kubernetes.io/component: admission-webhook
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx-admission-patch
  namespace: ingress-nginx
spec:
  template:
    metadata:
      labels:
        app.kubernetes.io/component: admission-webhook
        app.kubernetes.io/instance: ingress-nginx
        app.kubernetes.io/managed-by: Helm
        app.kubernetes.io/name: ingress-nginx
        app.kubernetes.io/part-of: ingress-nginx
        app.kubernetes.io/version: 1.1.2
        helm.sh/chart: ingress-nginx-4.0.18
      name: ingress-nginx-admission-patch
    spec:
      containers:
        - args:
            - patch
            - --webhook-name=ingress-nginx-admission
            - --namespace=$(POD_NAMESPACE)
            - --patch-mutating=false
            - --secret-name=ingress-nginx-admission
            - --patch-failure-policy=Fail
          env:
            - name: POD_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
          image: k8s.gcr.io/ingress-nginx/kube-webhook-certgen:v1.1.1 #修改镜像地址
          imagePullPolicy: IfNotPresent
          name: patch
          securityContext:
            allowPrivilegeEscalation: false
      nodeSelector:
        kubernetes.io/os: linux
      restartPolicy: OnFailure
      securityContext:
        fsGroup: 2000
        runAsNonRoot: true
        runAsUser: 2000
      serviceAccountName: ingress-nginx-admission
---
apiVersion: networking.k8s.io/v1
kind: IngressClass
metadata:
  labels:
    app.kubernetes.io/component: controller
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: nginx
spec:
  controller: k8s.io/ingress-nginx
---
apiVersion: admissionregistration.k8s.io/v1
kind: ValidatingWebhookConfiguration
metadata:
  labels:
    app.kubernetes.io/component: admission-webhook
    app.kubernetes.io/instance: ingress-nginx
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
    app.kubernetes.io/version: 1.1.2
    helm.sh/chart: ingress-nginx-4.0.18
  name: ingress-nginx-admission
webhooks:
  - admissionReviewVersions:
      - v1
    clientConfig:
      service:
        name: ingress-nginx-controller-admission
        namespace: ingress-nginx
        path: /networking/v1/ingresses
    failurePolicy: Fail
    matchPolicy: Equivalent
    name: validate.nginx.ingress.kubernetes.io
    rules:
      - apiGroups:
          - networking.k8s.io
        apiVersions:
          - v1
        operations:
          - CREATE
          - UPDATE
        resources:
          - ingresses
    sideEffects: None

4.部署 Ingress-nginx

4.1 准备工作
给 node2 节点打了app=ingress标签，因为上面的ingress-nginx-controller 使用的是 hostNetwork 模式（只会放pod真实pod 的端口） + nodeSelector
`kubectl label node kubec-node-2 app=ingress`

4.2 部署 kubect apply -f
`kubectl apply -f deploy.yaml #通过 kubectl apply 命令进行部署，前提是镜像准备好，否则GG`

4.3 查看状态
`kubectl get all -n ingress-nginx #查看 ingress-nginx namespace的部署情 kubectl logs -f ingress-nginx-controller-744f6d5bdf-tl6g4 -n ingress-nginx # 查看 ingress-nginx-controller 的日志情况`

4.4 测试访问

直接访问 kube-node-2的 ip 即可，因为 ingress-nginx-controller 默认是监听 80端口，由于上面的 nodeSelector: #选择 node label 中有 app=ingress的节点进行部署 ,而 kube-node-2 是被打了标签的节点node

可以看到其实就是一个 nginx

5.部署一个 tomcat 测试 Ingress-nginx

通过部署一个tomcat ，测试Ingress-nginx的代理是否生效

5.1 编写 deploy-tomcat.yaml

主要编写

Deployment 部署tomcat:8.0-alpine，
Service 暴露 tomcat pod
一个 Ingress 资源它规定访问 tomcat.demo.com 这个域名的所有请求 / 都转发到 tomcat-demo Service 上
IngressClass 新版本提供的资源，用于在定义 Ingress资源的时候指定，在集群中有多个 Ingress controller 的时候很有用处
```
apiVersion: apps/v1
kind: Deployment
metadata:
  name: tomcat-demo
spec:
  selector:
    matchLabels:
      app: tomcat-demo
  replicas: 1
  template:
    metadata:
      labels:
        app: tomcat-demo
    spec:
      containers:
      - name: tomcat-demo
        image: tomcat:8.0-alpine
        ports:
        - containerPort: 8080
---

apiVersion: v1
kind: Service
metadata:
  name: tomcat-demo
spec:
  selector:
    app: tomcat-demo #选择 tomcat-demo pod 
  ports:
  - port: 80 #对外暴露 80 端口
    protocol: TCP
    targetPort: 8080 # tomcat 端口


---

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: tomcat-demo
spec:
  defaultBackend:
    service:
      name: default-http-backend #！！！ 指定 默认的backend服务 
      port: 
      	number: 80 
  ingressClassName: nginx #！！！重点 需要指定 哪个 IngressClass 可以看上面的 deploy.yaml 最后定义的
  rules:
  - host: tomcat.demo.com #所有的  tomcat.demo.com请求都转发到  Service tomcat-demo
    http:
      paths:
      - pathType: Prefix
        path: "/"
        backend:
          service:
            name: tomcat-demo
            port: 
              number: 80
              
---
#定义一个 default-http-backend 当没有被Ingress规定的请求 负载给 它
apiVersion: apps/v1
kind: Deployment
metadata:
  name: default-http-backend
  labels:
    app: default-http-backend
spec:
  replicas: 1
  selector:
    matchLabels:
      app: default-http-backend
  template:
    metadata:
      labels:
        app: default-http-backend
    spec:
      terminationGracePeriodSeconds: 60
      containers:
      - name: default-http-backend
        # Any image is permissible as long as:
        # 1. It serves a 404 page at /
        # 2. It serves 200 on a /healthz endpoint
        image: registry.cn-hangzhou.aliyuncs.com/google_containers/defaultbackend:1.4
        livenessProbe:
          httpGet:
            path: /healthz
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 30
          timeoutSeconds: 5
        ports:
        - containerPort: 8080
        resources:
          limits:
            cpu: 10m
            memory: 20Mi
          requests:
            cpu: 10m
            memory: 20Mi
---
 
apiVersion: v1
kind: Service
metadata:
  name: default-http-backend
  labels:
    app: default-http-backend
spec:
  ports:
  - port: 80
    targetPort: 8080
  selector:
    app: default-http-backend
```
5.2 部署 tomcat + ingress + default-http-backend
部署上面的文件即可

查看部署情况可以看到都是Running 了

5.3 测试通过Ingress-nginx 能否访问到tomcat

由于我们 ingress 资源配置的域名是 tomcat.demo.com ，所以我需要把它添加到宿主机的hosts 文件中，如下

那么按照预期，当我访问 tomcat.demo.com 的时候其实就是访问 192.168.56.22 上的 ingress-nginx-controller 这个nginx，那么根据 ingress 的资源的设定它会把请求转发到 Service tomcat-demo 上，从而访问到 tomcat 界面

当我访问 api.demo.com 的时候由于没有对这个域名进行处理那么会默认把请求转发到 default-http-backend 上

总结

至此在k8s 1.23.5上已经成功部署了 Ingress-nginx ，并且通过部署一个tomcat服务测试了 Ingress-nginx 已经代理成功了，由于不管是 k8s 新版本和 Ingress-nginx 新版本都有些变化所有很些坑，是我从官网不断摸索的，下面总结一下坑点
- image 镜像需要自己从docker hub 上准备好，或者直接修改Ingress-nginx 的 deploy.yaml
  k8s.gcr.io/ingress-nginx/controller:v1.1.2
  
  k8s.gcr.io/ingress-nginx/kube-webhook-certgen:v1.1.1
- 重要！新版本中提供了 IngressClass ，需要在编写 Ingress 的时候指定
- 把 ingress-nginx-controller 使用 hostNetwork: true 进行部署比 NodePort 减少一层转发，但是需要指定选择打了标签的 node nodeSelector: app: ingress
- 通过 Ingress spec.defaultBackend 指定默认服务，并且需要保持在同一个 namespace
```
spec:
	defaultBackend:
    service:
      name: default-http-backend #！！！ 指定 默认的backend服务 
      port: 
      	number: 80 
```
- vscode k8s 插件快捷生成Depoyment 的时候自定添加了资源限制，导致部署tomcat的时候总是启动不起来..
  导致tomcat pod 状态 CrashLoopBackOff，从而导致通过 Ingress-nginx 无法访问到tomcat
```
resources:
  limits:
    memory: "128Mi" #不够部署tomcat 内存
    cpu: "500m"
```