Ingress是什么
在Kubernetes中，Ingress是一种用于将外部流量路由到集群内部服务的API对象。它通常与Ingress控制器一起使用，Ingress控制器负责根据Ingress规则路由外部流量到不同的服务上。
Ingress 提供从集群外部到集群内服务的 HTTP 和 HTTPS 路由。 流量路由由 Ingress 资源所定义的规则来控制。
通过配置，Ingress 可为 Service 提供外部可访问的 URL、对其流量作负载均衡、 终止 SSL/TLS，以及基于名称的虚拟托管等能力。 Ingress 控制器 负责完成 Ingress 的工作，具体实现上通常会使用某个负载均衡器， 不过也可以配置边缘路由器或其他前端来帮助处理流量。
下图是一个简单的Ingress示例，可将流量发送到同一个ingress
不使用Ingress资源的话，也有多种暴露service 的方法，例如
1、使用 Service.Type=NodePort
2、使用 Service.Type=LoadBalancer
前面也提到，Ingress资源要正常工作，集群必须有一个正在运行的 Ingress 控制器， Ingress 控制器不是随集群自动启动的，目前k8s项目中，支持和维护 AWS、 GCE 和 Nginx Ingress 控制器；当然也有一起其他三方的控制器可使用；
安装ingress
这里我们选用ingress-nginx控制器
1.下载ingress配置文件
wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v0.47.0/deploy/static/provider/baremetal/deploy.yaml
2.修改yaml文件中的镜像来源
#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
注意：配置文件中除了镜像的地址改后，ingress-nginx-controller的Service默认的type、ingress-nginx-controller的Deployment的配置中的hostNetwork也按照需求改一下
3.检查安装结果
# 应用资源文件
kubectl apply -f deploy.yaml
# 检查安装的结果
kubectl get pod,svc -n ingress-nginx
若文件下载不来，安装不了，可使用以下yaml文件，这是一个yaml文件的内容
apiVersion: v1
kind: Namespace
metadata:name: ingress-nginxlabels:app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginx---
# Source: ingress-nginx/templates/controller-serviceaccount.yaml
apiVersion: v1
kind: ServiceAccount
metadata:labels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: controllername: ingress-nginxnamespace: ingress-nginx
automountServiceAccountToken: true
---
# Source: ingress-nginx/templates/controller-configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:labels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: controllername: ingress-nginx-controllernamespace: ingress-nginx
data:
---
# Source: ingress-nginx/templates/clusterrole.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:labels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmname: ingress-nginx
rules:- apiGroups:- ''resources:- configmaps- endpoints- nodes- pods- secretsverbs:- list- watch- apiGroups:- ''resources:- nodesverbs:- get- apiGroups:- ''resources:- servicesverbs:- get- list- watch- apiGroups:- extensions- networking.k8s.io # k8s 1.14+resources:- ingressesverbs:- get- list- watch- apiGroups:- ''resources:- eventsverbs:- create- patch- apiGroups:- extensions- networking.k8s.io # k8s 1.14+resources:- ingresses/statusverbs:- update- apiGroups:- networking.k8s.io # k8s 1.14+resources:- ingressclassesverbs:- get- list- watch
---
# Source: ingress-nginx/templates/clusterrolebinding.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:labels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmname: ingress-nginx
roleRef:apiGroup: rbac.authorization.k8s.iokind: ClusterRolename: ingress-nginx
subjects:- kind: ServiceAccountname: ingress-nginxnamespace: ingress-nginx
---
# Source: ingress-nginx/templates/controller-role.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:labels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: controllername: ingress-nginxnamespace: ingress-nginx
rules:- apiGroups:- ''resources:- namespacesverbs:- get- apiGroups:- ''resources:- configmaps- pods- secrets- endpointsverbs:- get- list- watch- apiGroups:- ''resources:- servicesverbs:- get- list- watch- apiGroups:- extensions- networking.k8s.io # k8s 1.14+resources:- ingressesverbs:- get- list- watch- apiGroups:- extensions- networking.k8s.io # k8s 1.14+resources:- ingresses/statusverbs:- update- apiGroups:- networking.k8s.io # k8s 1.14+resources:- ingressclassesverbs:- get- list- watch- apiGroups:- ''resources:- configmapsresourceNames:- ingress-controller-leader-nginxverbs:- get- update- apiGroups:- ''resources:- configmapsverbs:- create- apiGroups:- ''resources:- eventsverbs:- create- patch
---
# Source: ingress-nginx/templates/controller-rolebinding.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:labels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: controllername: ingress-nginxnamespace: ingress-nginx
roleRef:apiGroup: rbac.authorization.k8s.iokind: Rolename: ingress-nginx
subjects:- kind: ServiceAccountname: ingress-nginxnamespace: ingress-nginx
---
# Source: ingress-nginx/templates/controller-service-webhook.yaml
apiVersion: v1
kind: Service
metadata:labels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: controllername: ingress-nginx-controller-admissionnamespace: ingress-nginx
spec:type: ClusterIPports:- name: https-webhookport: 443targetPort: webhookselector:app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/component: controller
---
# Source: ingress-nginx/templates/controller-service.yaml
apiVersion: v1
kind: Service
metadata:annotations:labels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: controllername: ingress-nginx-controllernamespace: ingress-nginx
spec:type: NodePortports:- name: httpport: 80protocol: TCPtargetPort: http- name: httpsport: 443protocol: TCPtargetPort: httpsselector:app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/component: controller
---
# Source: ingress-nginx/templates/controller-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:labels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: controllername: ingress-nginx-controllernamespace: ingress-nginx
spec:selector:matchLabels:app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/component: controllerrevisionHistoryLimit: 10minReadySeconds: 0template:metadata:labels:app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/component: controllerspec:dnsPolicy: ClusterFirstcontainers:- name: controllerimage: registry.cn-hangzhou.aliyuncs.com/lfy_k8s_images/ingress-nginx-controller:v0.46.0imagePullPolicy: IfNotPresentlifecycle:preStop:exec:command:- /wait-shutdownargs:- /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/keysecurityContext:capabilities:drop:- ALLadd:- NET_BIND_SERVICErunAsUser: 101allowPrivilegeEscalation: trueenv:- name: POD_NAMEvalueFrom:fieldRef:fieldPath: metadata.name- name: POD_NAMESPACEvalueFrom:fieldRef:fieldPath: metadata.namespace- name: LD_PRELOADvalue: /usr/local/lib/libmimalloc.solivenessProbe:failureThreshold: 5httpGet:path: /healthzport: 10254scheme: HTTPinitialDelaySeconds: 10periodSeconds: 10successThreshold: 1timeoutSeconds: 1readinessProbe:failureThreshold: 3httpGet:path: /healthzport: 10254scheme: HTTPinitialDelaySeconds: 10periodSeconds: 10successThreshold: 1timeoutSeconds: 1ports:- name: httpcontainerPort: 80protocol: TCP- name: httpscontainerPort: 443protocol: TCP- name: webhookcontainerPort: 8443protocol: TCPvolumeMounts:- name: webhook-certmountPath: /usr/local/certificates/readOnly: trueresources:requests:cpu: 100mmemory: 90MinodeSelector:kubernetes.io/os: linuxserviceAccountName: ingress-nginxterminationGracePeriodSeconds: 300volumes:- name: webhook-certsecret: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-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: admission-webhookname: ingress-nginx-admission
webhooks:- name: validate.nginx.ingress.kubernetes.iomatchPolicy: Equivalentrules:- apiGroups:- networking.k8s.ioapiVersions:- v1beta1operations:- CREATE- UPDATEresources:- ingressesfailurePolicy: FailsideEffects: NoneadmissionReviewVersions:- v1- v1beta1clientConfig:service:namespace: ingress-nginxname: ingress-nginx-controller-admissionpath: /networking/v1beta1/ingresses
---
# Source: ingress-nginx/templates/admission-webhooks/job-patch/serviceaccount.yaml
apiVersion: v1
kind: ServiceAccount
metadata:name: ingress-nginx-admissionannotations:helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgradehelm.sh/hook-delete-policy: before-hook-creation,hook-succeededlabels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: admission-webhooknamespace: ingress-nginx
---
# Source: ingress-nginx/templates/admission-webhooks/job-patch/clusterrole.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:name: ingress-nginx-admissionannotations:helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgradehelm.sh/hook-delete-policy: before-hook-creation,hook-succeededlabels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: admission-webhook
rules:- apiGroups:- admissionregistration.k8s.ioresources:- validatingwebhookconfigurationsverbs:- get- update
---
# Source: ingress-nginx/templates/admission-webhooks/job-patch/clusterrolebinding.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:name: ingress-nginx-admissionannotations:helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgradehelm.sh/hook-delete-policy: before-hook-creation,hook-succeededlabels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: admission-webhook
roleRef:apiGroup: rbac.authorization.k8s.iokind: ClusterRolename: ingress-nginx-admission
subjects:- kind: ServiceAccountname: ingress-nginx-admissionnamespace: ingress-nginx
---
# Source: ingress-nginx/templates/admission-webhooks/job-patch/role.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:name: ingress-nginx-admissionannotations:helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgradehelm.sh/hook-delete-policy: before-hook-creation,hook-succeededlabels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: admission-webhooknamespace: ingress-nginx
rules:- apiGroups:- ''resources:- secretsverbs:- get- create
---
# Source: ingress-nginx/templates/admission-webhooks/job-patch/rolebinding.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:name: ingress-nginx-admissionannotations:helm.sh/hook: pre-install,pre-upgrade,post-install,post-upgradehelm.sh/hook-delete-policy: before-hook-creation,hook-succeededlabels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: admission-webhooknamespace: ingress-nginx
roleRef:apiGroup: rbac.authorization.k8s.iokind: Rolename: ingress-nginx-admission
subjects:- kind: ServiceAccountname: ingress-nginx-admissionnamespace: ingress-nginx
---
# Source: ingress-nginx/templates/admission-webhooks/job-patch/job-createSecret.yaml
apiVersion: batch/v1
kind: Job
metadata:name: ingress-nginx-admission-createannotations:helm.sh/hook: pre-install,pre-upgradehelm.sh/hook-delete-policy: before-hook-creation,hook-succeededlabels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: admission-webhooknamespace: ingress-nginx
spec:template:metadata:name: ingress-nginx-admission-createlabels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: admission-webhookspec:containers:- name: createimage: docker.io/jettech/kube-webhook-certgen:v1.5.1imagePullPolicy: IfNotPresentargs:- create- --host=ingress-nginx-controller-admission,ingress-nginx-controller-admission.$(POD_NAMESPACE).svc- --namespace=$(POD_NAMESPACE)- --secret-name=ingress-nginx-admissionenv:- name: POD_NAMESPACEvalueFrom:fieldRef:fieldPath: metadata.namespacerestartPolicy: OnFailureserviceAccountName: ingress-nginx-admissionsecurityContext:runAsNonRoot: truerunAsUser: 2000
---
# Source: ingress-nginx/templates/admission-webhooks/job-patch/job-patchWebhook.yaml
apiVersion: batch/v1
kind: Job
metadata:name: ingress-nginx-admission-patchannotations:helm.sh/hook: post-install,post-upgradehelm.sh/hook-delete-policy: before-hook-creation,hook-succeededlabels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: admission-webhooknamespace: ingress-nginx
spec:template:metadata:name: ingress-nginx-admission-patchlabels:helm.sh/chart: ingress-nginx-3.33.0app.kubernetes.io/name: ingress-nginxapp.kubernetes.io/instance: ingress-nginxapp.kubernetes.io/version: 0.47.0app.kubernetes.io/managed-by: Helmapp.kubernetes.io/component: admission-webhookspec:containers:- name: patchimage: docker.io/jettech/kube-webhook-certgen:v1.5.1imagePullPolicy: IfNotPresentargs:- patch- --webhook-name=ingress-nginx-admission- --namespace=$(POD_NAMESPACE)- --patch-mutating=false- --secret-name=ingress-nginx-admission- --patch-failure-policy=Failenv:- name: POD_NAMESPACEvalueFrom:fieldRef:fieldPath: metadata.namespacerestartPolicy: OnFailureserviceAccountName: ingress-nginx-admissionsecurityContext:runAsNonRoot: truerunAsUser: 2000
ingress-nginx控制器的官网地址：https://kubernetes.github.io/ingress-nginx/
测试
1、首先我在集群中创建了两个deployment应用，配置文件如下：
apiVersion: apps/v1
kind: Deployment
metadata:name: hello-server
spec:replicas: 2selector:matchLabels:app: hello-servertemplate:metadata:labels:app: hello-serverspec:containers:- name: hello-serverimage: registry.cn-hangzhou.aliyuncs.com/lfy_k8s_images/hello-serverports:- containerPort: 9000
---
apiVersion: apps/v1
kind: Deployment
metadata:labels:app: nginx-demoname: nginx-demo
spec:replicas: 2selector:matchLabels:app: nginx-demotemplate:metadata:labels:app: nginx-demospec:containers:- image: nginxname: nginx
2、deployment创建完毕后，将这两个应用抽离成对应的service，type为clusterIP；
apiVersion: v1
kind: Service
metadata:labels:app: nginx-demoname: nginx-demo
spec:selector:app: nginx-demoports:- port: 8000protocol: TCPtargetPort: 80
---
apiVersion: v1
kind: Service
metadata:labels:app: hello-servername: hello-server
spec:selector:app: hello-serverports:- port: 8000protocol: TCPtargetPort: 9000
3、配置域名访问；我自己电脑的hosts文件已经配置好了域名解析
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:name: ingress-host-bar
spec:ingressClassName: nginxrules:- host: "hello.wtl.com"http:paths:- pathType: Prefixpath: "/"backend:service:name: hello-serverport:number: 8000- host: "demo.wtl.com"http:paths:- pathType: Prefixpath: "/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404backend:service:name: nginx-demo ## java，比如使用路径重写，去掉前缀nginxport:number: 8000
4、浏览器访问，因为前面我们使用kubectl命令时，看到http/https协议映射的端口是30528、31698，那域名访问时也要拼上对应端口
可以看到ingress已经配置成功了！
路径重写
这里主要使用了nginx.ingress.kubernetes.io/rewrite-target注解
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:annotations:nginx.ingress.kubernetes.io/rewrite-target: /$2name: ingress-host-bar
spec:ingressClassName: nginxrules:- host: "hello.wtl.com"http:paths:- pathType: Prefixpath: "/"backend:service:name: hello-serverport:number: 8000- host: "demo.wtl.com"http:paths:- pathType: Prefixpath: "/nginx(/|$)(.*)" # 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404backend:service:name: nginx-demo ## java，比如使用路径重写，去掉前缀nginxport:number: 8000
这里路径重写的意思是：
访问路径符合，demo.wtl.com/nginx/newPath这些路径的，都将会被重写到demo.wtl.com/newPath；例如：
- demo.wtl.com/nginx重写到demo.wtl.com/
- demo.wtl.com/nginx/重写到demo.wtl.com/
- demo.wtl.com/nginx/newPath重写到demo.wtl.com/newPath
详细的说明可以参考官网：https://kubernetes.github.io/ingress-nginx/examples/rewrite/
测试：
![[C++]红黑树](https://img-blog.csdnimg.cn/direct/b39fa07b98c941d2bda8d0915e89aaf0.png)
