kubernetes资源对象介绍及常用命令（四）

Ingress

Service的统一网关入口。

一、安装

# 下载yaml
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

# 安装
kubectl apply -f deploy.yaml

# 检查安装的结果
[[email protected] ~]# kubectl get pod,svc -n ingress-nginx
NAME                                            READY   STATUS      RESTARTS   AGE
pod/ingress-nginx-admission-create-krsnv        0/1     Completed   0          8m59s
pod/ingress-nginx-admission-patch-ffc6m         0/1     Completed   3          8m59s
pod/ingress-nginx-controller-65bf56f7fc-bh7ds   1/1     Running     0          8m59s

NAME                                         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)                      AGE
service/ingress-nginx-controller             NodePort    10.96.156.255   <none>        80:30290/TCP,443:31608/TCP   8m59s
service/ingress-nginx-controller-admission   ClusterIP   10.96.54.191    <none>        443/TCP                      8m59s
[[email protected] ~]# 

Ingress还是以NodePort的形式暴露端口。

如果下载不到，用以下文件，ingress.yml

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

二、实战使用

官网资料：https://kubernetes.github.io/ingress-nginx/

预期效果：通过不同的域名访问服务，流量转发到不同的pod中。

1、环境准备

ingress_test.yml

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

[[email protected] ~]# kubectl apply -f ingress_test.yml
deployment.apps/hello-server created
deployment.apps/nginx-demo created
service/nginx-demo created
service/hello-server created
[[email protected] ~]# 

做了两次部署hello-server和nginx-demo。创建了两个Service，hello-server和nginx-demo。

2. 域名访问

创建Ingress，分别给两个Service，hello-server和nginx-demo绑定到域名hello.ingress.com和demo.ingress.com。

apiVersion: networking.k8s.io/v1
kind: Ingress  
metadata:
  name: ingress-host-bar
spec:
  ingressClassName: nginx
  rules:
  - host: "hello.ingress.com"
    http:
      paths:
      - pathType: Prefix
        path: "/"
        backend:
          service:
            name: hello-server
            port:
              number: 8000
  - host: "demo.ingress.com"
    http:
      paths:
      - pathType: Prefix
        path: "/nginx"  
        backend:
          service:
            name: nginx-demo  
            port:
              number: 8000

[[email protected] ~]# kubectl apply -f ingress_test_ingress.yml
ingress.networking.k8s.io/ingress-host-bar created
[[email protected] ~]#

注意在测试的时候要修改本地hosts文件。

这样就实现了不同的域名首先经过ingress的处理，将它转发给不同的service，然后由相应的pod提供服务。

注意path: "/nginx" 与 path: "/" 的不同的效果，在请求路径时会有所不同。ingress本身也是nginx做的，有时看到nginx的404页面，需要辨别是ingress返回的，还是其下的nginx应用返回的。

3. 路径重写

https://kubernetes.github.io/ingress-nginx/examples/rewrite/

apiVersion: networking.k8s.io/v1
kind: Ingress  
metadata:
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /$2
  name: ingress-host-bar
spec:
  ingressClassName: nginx
  rules:
  - host: "hello.ingress.com"
    http:
      paths:
      - pathType: Prefix
        path: "/"
        backend:
          service:
            name: hello-server
            port:
              number: 8000
  - host: "demo.ingress.com"
    http:
      paths:
      - pathType: Prefix
        path: "/nginx(/|$)(.*)"
        backend:
          service:
            name: nginx-demo  
            port:
              number: 8000

相比于域名访问多加了一行注解nginx.ingress.kubernetes.io/rewrite-target: /$2，并且修改path: "/nginx(/|$)(.*)"。这样做当我们访问http://demo.ingress.com:30290/nginx时实际上还是访问的http://demo.ingress.com:30290，实现了路径重写。

4. 流量限制

https://kubernetes.github.io/ingress-nginx/user-guide/nginx-configuration/annotations/#rate-limiting

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

相比于域名访问多了注解nginx.ingress.kubernetes.io/limit-rps: "1"，表示每秒只能进行1次访问，如果访问过快，就会出现503的错误信息。

扩展：pathType除了Prefix表示前缀，还拥有一种是Exact，表示精确访问，只有访问路径符合path要求，才会有相应的返回结果。

查看ingress

[[email protected] ~]# kubectl get ing
NAME               CLASS   HOSTS                                ADDRESS      PORTS   AGE
ingress-host-bar   nginx   hello.ingress.com,demo.ingress.com   172.31.0.4   80      3h26m
[[email protected] ~]# 

修改ingress

[[email protected] ~]# kubectl edit ing ingress-host-bar
Edit cancelled, no changes made.
[[email protected] ~]# 

删除ingress

[[email protected] ~]# kubectl delete ing ingress-host-bar
ingress.networking.k8s.io "ingress-host-bar" deleted
[[email protected] ~]# 

小结：

kubernetes网络模型

Ingress相当于流量的总入口，LB是Ingress的负载均衡，Ingress是Service的负载均衡，Service是Pod的负载均衡。

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