k8s 新版本 部署 Ingress-nginx controller

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 文件

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:v1.1.2

k8s.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 部署情况

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

访问 tomcat.demo.com

访问 api.demo.com

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"
  

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