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诺禾

作者:互联网

说来抱歉,这是一篇迟到半年的博文,我的ASP.NET Core on K8s学习系列博文很久没更新了,于是乎趁着周末补了一篇Ingress部分,希望对你有用。

1关于Ingress

Kubernetes对外暴露Service主要有三种方式:NodePort、LoadBalancer 以及 Ingress。前两种我们在本系列的第四篇《你必须知道的Service》一文中已经加以介绍,这里我们主要来看看Ingress是个什么鬼。

官网对 Ingress 的定义为 管理对外服务到集群内服务之间规则的集合,通俗点讲就是它定义规则来允许进入集群的请求被转发到集群中对应服务上,从来实现服务暴漏。Ingress 能把集群内 Service 配置成外网能够访问的 URL,流量负载均衡,终止SSL,提供基于域名访问的虚拟主机等等。

我们可以再次回顾一下我们通常访问一个业务的流程:

ASP.NET Core on K8s学习之旅(12)Ingress

了解了整个流程,我们再结合官网的定义来看Ingress,可以知道Ingress就是一个K8S集群业务的入口,一个统一访问入口。我们可以使用Traefik、Istio、Nginx、HAProxy来作为Ingress使用,这里我们主要介绍Nginx Ingress,因为我们比较熟悉Nginx一些。

2Nginx Ingress的安装配置

这里我们在k8s-master上执行以下的yaml文件来通过DaemonSet的方式部署Nginx Ingress,这个yaml文件可以从ingress-nginx的github上获取,这里我选择的是0.30.0版本。

获取方式:https://github.com/kubernetes/ingress-nginx/tree/nginx-0.30.0/deploy

ASP.NET Core on K8s学习之旅(12)IngressASP.NET Core on K8s学习之旅(12)Ingress

在static目录下,将mandatory.yaml文件获取下来如下代码所示,这里我做了一点修改(注意我标红的配置):

(1)将原本为Deployment的类型换为了DaemonSet

(2)为Ingress-Controller增加hostNetwork: true的配置,即直接占用宿主机80/443端口

(3)将Ingress-Controller部署到有ingressHost: yes这个label的Node节点上,即我的k8s-node1服务器上

(4)将Ingress-Controller的镜像源改为阿里云镜像仓库:registry.cn-hangzhou.aliyuncs.com

apiVersion: v1kind: Namespacemetadata: name: ingress-nginx labels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginx
---
kind: ConfigMapapiVersion: v1metadata: name: nginx-configuration namespace: ingress-nginx labels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginx
---kind: ConfigMapapiVersion: v1metadata: name: tcp-services namespace: ingress-nginx labels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginx
---kind: ConfigMapapiVersion: v1metadata: name: udp-services namespace: ingress-nginx labels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginx
---apiVersion: v1kind: ServiceAccountmetadata: name: nginx-ingress-serviceaccount namespace: ingress-nginx labels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginx
---apiVersion: rbac.authorization.k8s.io/v1beta1kind: ClusterRolemetadata: name: nginx-ingress-clusterrole labels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginxrules: - apiGroups: - "" resources: - configmaps - endpoints - nodes - pods - secrets verbs: - list - watch - apiGroups: - "" resources: - nodes verbs: - get - apiGroups: - "" resources: - services verbs: - get - list - watch - apiGroups: - "" resources: - events verbs: - create - patch - apiGroups: - "extensions" - "networking.k8s.io" resources: - ingresses verbs: - get - list - watch - apiGroups: - "extensions" - "networking.k8s.io" resources: - ingresses/status verbs: - update
---apiVersion: rbac.authorization.k8s.io/v1beta1kind: Rolemetadata: name: nginx-ingress-role namespace: ingress-nginx labels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginxrules: - apiGroups: - "" resources: - configmaps - pods - secrets - namespaces verbs: - get - apiGroups: - "" resources: - configmaps resourceNames: # Defaults to "<election-id>-<ingress-class>" # Here: "<ingress-controller-leader>-<nginx>" # This has to be adapted if you change either parameter # when launching the nginx-ingress-controller. - "ingress-controller-leader-nginx" verbs: - get - update - apiGroups: - "" resources: - configmaps verbs: - create - apiGroups: - "" resources: - endpoints verbs: - get
---apiVersion: rbac.authorization.k8s.io/v1beta1kind: RoleBindingmetadata: name: nginx-ingress-role-nisa-binding namespace: ingress-nginx labels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginxroleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: nginx-ingress-rolesubjects: - kind: ServiceAccount name: nginx-ingress-serviceaccount namespace: ingress-nginx
---apiVersion: rbac.authorization.k8s.io/v1beta1kind: ClusterRoleBindingmetadata: name: nginx-ingress-clusterrole-nisa-binding labels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginxroleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: nginx-ingress-clusterrolesubjects: - kind: ServiceAccount name: nginx-ingress-serviceaccount namespace: ingress-nginx
---
apiVersion: apps/v1kind: DaemonSetmetadata: name: nginx-ingress-controller namespace: ingress-nginx labels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginxspec: # replicas: 1 selector: matchLabels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginx template: metadata: labels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginx annotations: prometheus.io/port: "10254" prometheus.io/scrape: "true" spec: # wait up to five minutes for the drain of connections terminationGracePeriodSeconds: 300 serviceAccountName: nginx-ingress-serviceaccount nodeSelector: kubernetes.io/os: linux ingressHost: "yes" hostNetwork: true containers: - name: nginx-ingress-controller image: registry.cn-hangzhou.aliyuncs.com/google_containers/nginx-ingress-controller:0.30.0 args: - /nginx-ingress-controller - --configmap=$(POD_NAMESPACE)/nginx-configuration - --tcp-services-configmap=$(POD_NAMESPACE)/tcp-services - --udp-services-configmap=$(POD_NAMESPACE)/udp-services - --publish-service=$(POD_NAMESPACE)/ingress-nginx - --annotations-prefix=nginx.ingress.kubernetes.io securityContext: allowPrivilegeEscalation: true capabilities: drop: - ALL add: - NET_BIND_SERVICE # www-data -> 101 runAsUser: 101 env: - name: POD_NAME valueFrom: fieldRef: fieldPath: metadata.name - name: POD_NAMESPACE valueFrom: fieldRef: fieldPath: metadata.namespace ports: - name: http containerPort: 80 protocol: TCP - name: https containerPort: 443 protocol: TCP livenessProbe: failureThreshold: 3 httpGet: path: /healthz port: 10254 scheme: HTTP initialDelaySeconds: 10 periodSeconds: 10 successThreshold: 1 timeoutSeconds: 10 readinessProbe: failureThreshold: 3 httpGet: path: /healthz port: 10254 scheme: HTTP periodSeconds: 10 successThreshold: 1 timeoutSeconds: 10 lifecycle: preStop: exec: command: - /wait-shutdown
---
apiVersion: v1kind: LimitRangemetadata: name: ingress-nginx namespace: ingress-nginx labels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginxspec: limits: - min: memory: 90Mi cpu: 100m type: Container

这里顺便说下Ingress的两种部署方式:

(1)基于NodePort方式

ASP.NET Core on K8s学习之旅(12)Ingress

基于NodePort的部署思路就是通过在每个节点上开辟NodePort的端口,将流量引入进来,而后通过iptables首先转发到ingress-controller容器中(图中的nginx容器),而后由nginx根据ingress的规则进行判断,将其转发到对应的应用web容器中。

(2)基于HostNetwork方式

ASP.NET Core on K8s学习之旅(12)Ingress

相比较起来,HostNetwork模式不再需要创建一个nodePort的svc,而是直接在每个节点都创建一个ingress-controller的容器,而且将该容器的网络模式设为HostNetwork。也就是说每个节点物理机的80和443端口将会被ingress-controller中的nginx容器占用。当流量通过80/443端口进入时,将直接进入到nginx中。而后nginx根据ingress规则再将流量转发到对应的web应用容器中。

OK,两种模式我们就了解到这里,本文采用的是基于hostNetwork的方式占用宿主机80/443端口来作为流量入口。

然后,我们就可以运行创建命令来创建Ingress-Controller了:

kubectl apply -f mandatory.yaml

执行后的显示如下图所示,它会执行一系列的创建工作如namespace、configmap、serviceaccount、rbac以及daemonset等:

ASP.NET Core on K8s学习之旅(12)Ingress

Ingress-Controller创建好之后,我们再来创建一个指导Ingress进行路由转发的规则集ingress-nginx.yaml,其配置如下:

apiVersion: networking.k8s.io/v1beta1kind: Ingressmetadata: name: nginx-ingress namespace: xdp-poc annotations: kubernetes.io/ingress.class: "nginx" nginx.ingress.kubernetes.io/rewrite-target: /api/$2spec: rules: - host: portal.k8s.xi-life.cn http: paths: - path: /apple(/|$)(.*) backend: serviceName: apple-api-svc servicePort: 80 - path: /banana(/|$)(.*) backend: serviceName: banana-api-svc servicePort: 80

它的作用其实是帮助Nginx生成正确的Nginx.conf,帮助Nginx将请求转发不同的K8s集群中的Service入口进行处理。这里,我定义了两个后端Service服务,稍后我会介绍这两个Service,现在我们现将其创建一下:

kubectl apply -f ingress-nginx.yaml

好了,搭建和配置部分到此为止,下面我们可以准备刚刚提到的两个Service来进行一个简单的验证了。

3Nginx Ingress的使用验证

后端API项目准备

这里我准备两个ASP.NET Core WebAPI项目,他们的代码很简单,就只有一个HomeController,负责请求到api/home路由时返回一个json即可。

其中,AppleApi项目返回:

// GET api/home[HttpGet]public ActionResult<IEnumerable<string>> Get{ return new string { "AppleApi-Home", "v1.0", "Welcome to use AppleApi!" };}

BananaApi项目返回:

// GET api/home[HttpGet]public ActionResult<IEnumerable<string>> Get{ return new string { "BananaApi-Home", "v1.0", "Welcome to use BananaApi!" };}

这部分的代码文件可以在我的github上获取:

ASP.NET Core on K8s学习之旅(12)Ingress

然后,我们将这两个项目分别打一个docker镜像并上传到docker hub上,你可以直接使用我的镜像进行这个实验,具体的打包镜像和上传镜像的过程我就不演示了。

ASP.NET Core on K8s学习之旅(12)Ingress

直接拉取镜像:docker pull xilife/apple-api-demo:1.0 / docker pull xilife/banana-api-demo:1.0

部署yaml文件准备

接下来,我们就分别为两个API项目准备部署yaml文件,并应用该yaml文件创建pod和service:

(1)deploy-appleapi-svc.yaml

apiVersion: apps/v1kind: Deploymentmetadata: name: apple-api-demo namespace: xdp-poc labels: name: apple-api-demospec: replicas: 2 selector: matchLabels: name: apple-api-demo template: metadata: labels: name: apple-api-demo spec: containers: - name: apple-api-demo image: edisonsaonian/apple-api-demo:1.0 ports: - containerPort: 80 imagePullPolicy: IfNotPresent
---
kind: ServiceapiVersion: v1metadata: name: apple-api-svc namespace: xdp-pocspec: type: NodePort ports: - port: 80 targetPort: 80 selector: name: apple-api-demo

需要注意的就是:确保这里Service中定义的namespace(这里是xdp-poc)、服务名(这里是apple-api-svc)以及端口(这里是80)跟之前我们在ingress-nginx.yaml中设置的后端服务名和端口保持一致,否则无法实现请求转发。下面的BananaApi也是需要保持一致,就不再赘述。

(2)deploy-bananaapi-svc.yaml

apiVersion: apps/v1kind: Deploymentmetadata: name: banana-api-demo namespace: xdp-poc labels: name: banana-api-demospec: replicas: 2 selector: matchLabels: name: banana-api-demo template: metadata: labels: name: banana-api-demo spec: containers: - name: banana-api-demo image: edisonsaonian/banana-api-demo:1.0 ports: - containerPort: 80 imagePullPolicy: IfNotPresent
---
kind: ServiceapiVersion: v1metadata: name: banana-api-svc namespace: xdp-pocspec: type: NodePort ports: - port: 80 targetPort: 80 selector: name: banana-api-demo

最后,我们将其部署到K8s集群:

kubectl apply -f deploy-appleapi-svckubectl apply -f deploy-bananaapi-svc

现在可以通过kubectl看看是否已经Running:

ASP.NET Core on K8s学习之旅(12)Ingress

快速验证Ingress效果

由于我们设置的host是portal.k8s.xi-life.cn,因此我们现在自己的客户机上修改一下hosts文件(Windows的话在system32/etc/drivers/hosts)增加一条记录,然后就可以通过浏览器输入域名来进行访问测试了:

(1)apple-api

ASP.NET Core on K8s学习之旅(12)Ingress

(2)banana-api

ASP.NET Core on K8s学习之旅(12)Ingress

4小结

本文介绍了Ingress的基本概念与Nginx Ingress的安装与配置,然后通过部署两个ASP.NET Core WebAPI服务到K8s集群进行Ingress的快速验证。当然,我们也可以使用自己的网关来代替Ingress作为外部统一流量入口,也可以使用云产品的LoadBalancer或API网关来替代Ingress也都是可以的(如果在不缺钱的情况下,尽可能用云产品吧,把Ops的工作都交给云)。

后续更新计划:如果你对阿里云ACK服务(即搭建阿里云K8s集群)有兴趣,那么请继续关注我的公众号,后续会为你介绍如何搭建阿里云K8s集群及如何使用,敬请期待。

5参考资料

梁宽,《再也不踩坑的Kubernetes实战指南》

花田犯的错,《K8S Nginx Ingress介绍》

Lucie_xxm,《Ingress 统一访问入口》

Wang Teng,《K8s学习笔记-Nginx Ingress实现服务暴露》

烂泥,《K8s安装与配置Ingress》

.NET Core on K8s学习系列文章目录

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标签:Ingress,name,kubernetes,ingress,nginx,诺禾,io
来源: https://www.cnblogs.com/lovenuohe/p/12924116.html