Kubernetes服务网络Ingress网络模型分析、安装和高级用法

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1、Ingres简介

Ingress翻译过来是“入口”的意思，也就是说：K8S希望Ingress能成为整个k8s集群的流量入口；Ingress网络是一组规则，充当Kubernetes集群的入口点。

• Ingress：Service的统一网关入口
• Service：Pod的统一网关入口

所有流量首先进入Ingress，由Ingress转交给Service，最终由Service负载均衡后交到各个Pod应用。

Ingress其实就是nginx封装的一个API对象。，通常通过HTTP管理集群中服务的外部访问，是暴露服务的最有效方式。

2、Ingres网络模型分析

举例说明：

• 某个产品有三个服务：分别为订单服务+用户服务+产品服务
• 部署三台机子

1. 订单服务：部署了两个Pod应用分别在两台机子
2. 用户服务：部署了三个Pod应用分别在三台机子
3. 产品服务：部署了三个Pod应用分别在三台机子

首先形成了两层网络服务，如下图：

• Service层网络
• Pod层网络
  

通过增加Ingress网络层，统一Service网络层的网关。

最终形成三层网络的架构设计。

• Ingres网络层（最外层）
• Service网络层
• Pod网络层

3、安装Ingress

wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v0.47.0/deploy/static/provider/baremetal/deploy.yaml #修改镜像 vi deploy.yaml #将image的值改为如下值： registry.cn-hangzhou.aliyuncs.com/lfy_k8s_images/ingress-nginx-controller:v0.46.0 # 检查安装的结果 kubectl get pod,svc -n ingress-nginx # 最后别忘记把svc暴露的端口要放行 

注意两点：

1. 下载yml文件
2. 修改阿里云的镜像地址

使用yml进行安装Ingress
在集群中安装完Ingress后，会生成service，暴露两个端口供外部访问。

http /https

以NodePort方式暴露外部访问的端口

4、使用

官网地址：https://kubernetes.github.io/ingress-nginx/

4.1、搭建测试环境

测试环境：应用如下yaml，准备好测试环境

apiVersion: apps/v1 kind: Deployment metadata: name: hello-server spec: replicas: 2 selector: matchLabels: app: hello-server template: metadata: labels: app: hello-server spec: containers: - name: hello-server image: registry.cn-hangzhou.aliyuncs.com/lfy_k8s_images/hello-server ports: - containerPort: 9000 --- apiVersion: apps/v1 kind: Deployment metadata: labels: app: nginx-demo name: nginx-demo spec: replicas: 2 selector: matchLabels: app: nginx-demo template: metadata: labels: app: nginx-demo spec: containers: - image: nginx name: nginx --- apiVersion: v1 kind: Service metadata: labels: app: nginx-demo name: nginx-demo spec: selector: app: nginx-demo ports: - port: 8000 protocol: TCP targetPort: 80 --- apiVersion: v1 kind: Service metadata: labels: app: hello-server name: hello-server spec: selector: app: hello-server ports: - port: 8000 protocol: TCP targetPort: 9000 

上述yml说明：

以Deployment方式部署了两个应用，分别为：

1. hello-server： 镜像名hello-server：两个副本，暴露端口8000，目标端口9000
2. nginx-demo：镜像名nginx：两个副本，暴露端口8000，目标端口80

同时也生成对应的两个service，分别为：nginx-demo和hello-serve

4.2、域名访问

通过下面的yml文件，创建一个ingress资源。

apiVersion: networking.k8s.io/v1 kind: Ingress metadata: name: ingress-host-bar spec: ingressClassName: nginx rules: - host: "hello.atguigu.com" http: paths: - pathType: Prefix path: "/" backend: service: name: hello-server port: number: 8000 - host: "demo.atguigu.com" http: paths: - pathType: Prefix path: "/nginx" # 把请求会转给下面的服务，下面的服务一定要能处理这个路径，不能处理就是404 backend: service: name: nginx-demo  java，比如使用路径重写，去掉前缀nginx port: number: 8000 

访问规则描述：

• 访问域名hello.atguigu.com，会转到service：hello-server应用
• 访问域名demo.atguigu.com/nginx，会转到service：nginx-demo应用

问题： path: “/nginx” 与 path: “/” 为什么会有不同的效果？

回答：上述yaml中加了路径/nginx，如果访问域名中也加了/nginx路径，说明访问域名路径一直，Ingress会处理这个路径请求，然后转发到service层nginx-demo，从而service层nginx-demo将请求流量负载均衡到各个pod；如果访问域名路径不一致，Ingress就不能处理这个路径，也就起不到转发路由的作用，因为ingress本身就是nginx，所以页面也会显示nginx的404，但不一样的是：此时nginx不带版本号。

4.3、路径重写（高级用法）

apiVersion: networking.k8s.io/v1 kind: Ingress metadata: annotations: nginx.ingress.kubernetes.io/rewrite-target: /$2 name: ingress-host-bar spec: ingressClassName: nginx rules: - host: "hello.atguigu.com" http: paths: - pathType: Prefix path: "/" backend: service: name: hello-server port: number: 8000 - host: "demo.atguigu.com" http: paths: - pathType: Prefix path: "/nginx(/|$)(.*)" # 把请求会转给下面的服务，下面的服务一定要能处理这个路径，不能处理就是404 backend: service: name: nginx-demo  java，比如使用路径重写，去掉前缀nginx port: number: 8000 

4.4、流量限制（高级用法）

apiVersion: networking.k8s.io/v1 kind: Ingress metadata: name: ingress-limit-rate annotations: nginx.ingress.kubernetes.io/limit-rps: "1" spec: ingressClassName: nginx rules: - host: "haha.atguigu.com" http: paths: - pathType: Exact path: "/" backend: service: name: nginx-demo port: number: 8000 

说明：

1. exact：精确匹配路径类型
2. 配置rps每秒请求接受的请求数为1

如果超过配置中的限制，访问就会报503的错误，起到限流的作用。

5、总结

最终，k8s集群网络模型包括三层网络模型构成，即：

• Ingress层
• Service层
• Pod层

另外在实际工作中，也可以在Ingress层外部设置一个LoadBalance层，请求流量首先经过外部的LB负载均衡到各个机子，然后在Ingress、Service和Pod层之间传递。

附录：ingress-nginx安装的yml文件

apiVersion: v1 kind: Namespace metadata: name: ingress-nginx labels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx --- # Source: ingress-nginx/templates/controller-serviceaccount.yaml apiVersion: v1 kind: ServiceAccount metadata: labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: controller name: ingress-nginx namespace: ingress-nginx automountServiceAccountToken: true --- # Source: ingress-nginx/templates/controller-configmap.yaml apiVersion: v1 kind: ConfigMap metadata: labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: controller name: ingress-nginx-controller namespace: ingress-nginx data: --- # Source: ingress-nginx/templates/clusterrole.yaml apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRole metadata: labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm name: 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: - extensions - networking.k8s.io # k8s 1.14+ resources: - ingresses verbs: - get - list - watch - apiGroups: - '' resources: - events verbs: - create - patch - apiGroups: - extensions - networking.k8s.io # k8s 1.14+ resources: - ingresses/status verbs: - update - apiGroups: - networking.k8s.io # k8s 1.14+ resources: - ingressclasses verbs: - get - list - watch --- # Source: ingress-nginx/templates/clusterrolebinding.yaml apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm name: ingress-nginx roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: ingress-nginx subjects: - kind: ServiceAccount name: ingress-nginx namespace: ingress-nginx --- # Source: ingress-nginx/templates/controller-role.yaml apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: controller 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: - extensions - networking.k8s.io # k8s 1.14+ resources: - ingresses verbs: - get - list - watch - apiGroups: - extensions - networking.k8s.io # k8s 1.14+ resources: - ingresses/status verbs: - update - apiGroups: - networking.k8s.io # k8s 1.14+ resources: - ingressclasses verbs: - get - list - watch - apiGroups: - '' resources: - configmaps resourceNames: - ingress-controller-leader-nginx verbs: - get - update - apiGroups: - '' resources: - configmaps verbs: - create - apiGroups: - '' resources: - events verbs: - create - patch --- # Source: ingress-nginx/templates/controller-rolebinding.yaml apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: controller 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 --- # Source: ingress-nginx/templates/controller-service-webhook.yaml apiVersion: v1 kind: Service metadata: labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: controller name: ingress-nginx-controller-admission namespace: ingress-nginx spec: type: ClusterIP ports: - name: https-webhook port: 443 targetPort: webhook selector: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/component: controller --- # Source: ingress-nginx/templates/controller-service.yaml apiVersion: v1 kind: Service metadata: annotations: labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: controller name: ingress-nginx-controller namespace: ingress-nginx spec: type: NodePort ports: - name: http port: 80 protocol: TCP targetPort: http - name: https port: 443 protocol: TCP targetPort: https selector: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/component: controller --- # Source: ingress-nginx/templates/controller-deployment.yaml apiVersion: apps/v1 kind: Deployment metadata: labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: controller name: ingress-nginx-controller namespace: ingress-nginx spec: selector: matchLabels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/component: controller revisionHistoryLimit: 10 minReadySeconds: 0 template: metadata: labels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/component: controller spec: dnsPolicy: ClusterFirst containers: - name: controller image: registry.cn-hangzhou.aliyuncs.com/lfy_k8s_images/ingress-nginx-controller:v0.46.0 imagePullPolicy: IfNotPresent lifecycle: preStop: exec: command: - /wait-shutdown args: - /nginx-ingress-controller - --election-id=ingress-controller-leader - --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 securityContext: capabilities: drop: - ALL add: - NET_BIND_SERVICE runAsUser: 101 allowPrivilegeEscalation: true 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 livenessProbe: failureThreshold: 5 httpGet: path: /healthz port: 10254 scheme: HTTP initialDelaySeconds: 10 periodSeconds: 10 successThreshold: 1 timeoutSeconds: 1 readinessProbe: failureThreshold: 3 httpGet: path: /healthz port: 10254 scheme: HTTP initialDelaySeconds: 10 periodSeconds: 10 successThreshold: 1 timeoutSeconds: 1 ports: - name: http containerPort: 80 protocol: TCP - name: https containerPort: 443 protocol: TCP - name: webhook containerPort: 8443 protocol: TCP volumeMounts: - name: webhook-cert mountPath: /usr/local/certificates/ readOnly: true resources: requests: cpu: 100m memory: 90Mi nodeSelector: kubernetes.io/os: linux serviceAccountName: ingress-nginx terminationGracePeriodSeconds: 300 volumes: - name: webhook-cert secret: secretName: ingress-nginx-admission --- # Source: ingress-nginx/templates/admission-webhooks/validating-webhook.yaml # before changing this value, check the required kubernetes version # https://kubernetes.io/docs/reference/access-authn-authz/extensible-admission-controllers/#prerequisites apiVersion: admissionregistration.k8s.io/v1 kind: ValidatingWebhookConfiguration metadata: labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: admission-webhook name: ingress-nginx-admission webhooks: - name: validate.nginx.ingress.kubernetes.io matchPolicy: Equivalent rules: - apiGroups: - networking.k8s.io apiVersions: - v1beta1 operations: - CREATE - UPDATE resources: - ingresses failurePolicy: Fail sideEffects: None admissionReviewVersions: - v1 - v1beta1 clientConfig: service: namespace: ingress-nginx name: ingress-nginx-controller-admission path: /networking/v1beta1/ingresses --- # Source: ingress-nginx/templates/admission-webhooks/job-patch/serviceaccount.yaml apiVersion: v1 kind: ServiceAccount metadata: name: ingress-nginx-admission annotations: helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgrade helm.sh/hook-delete-policy: before-hook-creation,hook-succeeded labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: admission-webhook namespace: ingress-nginx --- # Source: ingress-nginx/templates/admission-webhooks/job-patch/clusterrole.yaml apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRole metadata: name: ingress-nginx-admission annotations: helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgrade helm.sh/hook-delete-policy: before-hook-creation,hook-succeeded labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: admission-webhook rules: - apiGroups: - admissionregistration.k8s.io resources: - validatingwebhookconfigurations verbs: - get - update --- # Source: ingress-nginx/templates/admission-webhooks/job-patch/clusterrolebinding.yaml apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: name: ingress-nginx-admission annotations: helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgrade helm.sh/hook-delete-policy: before-hook-creation,hook-succeeded labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: admission-webhook roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: ingress-nginx-admission subjects: - kind: ServiceAccount name: ingress-nginx-admission namespace: ingress-nginx --- # Source: ingress-nginx/templates/admission-webhooks/job-patch/role.yaml apiVersion: rbac.authorization.k8s.io/v1 kind: Role metadata: name: ingress-nginx-admission annotations: helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgrade helm.sh/hook-delete-policy: before-hook-creation,hook-succeeded labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: admission-webhook namespace: ingress-nginx rules: - apiGroups: - '' resources: - secrets verbs: - get - create --- # Source: ingress-nginx/templates/admission-webhooks/job-patch/rolebinding.yaml apiVersion: rbac.authorization.k8s.io/v1 kind: RoleBinding metadata: name: ingress-nginx-admission annotations: helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgrade helm.sh/hook-delete-policy: before-hook-creation,hook-succeeded labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: admission-webhook 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 --- # Source: ingress-nginx/templates/admission-webhooks/job-patch/job-createSecret.yaml apiVersion: batch/v1 kind: Job metadata: name: ingress-nginx-admission-create annotations: helm.sh/hook: pre-install,pre-upgrade helm.sh/hook-delete-policy: before-hook-creation,hook-succeeded labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: admission-webhook namespace: ingress-nginx spec: template: metadata: name: ingress-nginx-admission-create labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: admission-webhook spec: containers: - name: create image: docker.io/jettech/kube-webhook-certgen:v1.5.1 imagePullPolicy: IfNotPresent args: - create - --host=ingress-nginx-controller-admission,ingress-nginx-controller-admission.$(POD_NAMESPACE).svc - --namespace=$(POD_NAMESPACE) - --secret-name=ingress-nginx-admission env: - name: POD_NAMESPACE valueFrom: fieldRef: fieldPath: metadata.namespace restartPolicy: OnFailure serviceAccountName: ingress-nginx-admission securityContext: runAsNonRoot: true runAsUser: 2000 --- # Source: ingress-nginx/templates/admission-webhooks/job-patch/job-patchWebhook.yaml apiVersion: batch/v1 kind: Job metadata: name: ingress-nginx-admission-patch annotations: helm.sh/hook: post-install,post-upgrade helm.sh/hook-delete-policy: before-hook-creation,hook-succeeded labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: admission-webhook namespace: ingress-nginx spec: template: metadata: name: ingress-nginx-admission-patch labels: helm.sh/chart: ingress-nginx-3.33.0 app.kubernetes.io/name: ingress-nginx app.kubernetes.io/instance: ingress-nginx app.kubernetes.io/version: 0.47.0 app.kubernetes.io/managed-by: Helm app.kubernetes.io/component: admission-webhook spec: containers: - name: patch image: docker.io/jettech/kube-webhook-certgen:v1.5.1 imagePullPolicy: IfNotPresent args: - patch - --webhook-name=ingress-nginx-admission - --namespace=$(POD_NAMESPACE) - --patch-mutating=false - --secret-name=ingress-nginx-admission - --patch-failure-policy=Fail env: - name: POD_NAMESPACE valueFrom: fieldRef: fieldPath: metadata.namespace restartPolicy: OnFailure serviceAccountName: ingress-nginx-admission securityContext: runAsNonRoot: true runAsUser: 2000 

看似不起眼的日复一日，会在将来的某一天，突然让你看到坚持的意义。