Kubernetes用Helm安装Ingress并踩一下使用的坑 |
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Kubernetes用Helm安装Ingress并踩一下使用的坑
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# Kubernetes用Helm安装Ingress并踩一下使用的坑 # 前言 Ingress是Kubernetes一个非常重要的Controller，它类似一个路由转发的组件，可以让外界访问Kubernetes内部的Service。除了Ingress，还有NodePort、LoadBalance等方式，Ingress暴露给外界的方式还是很常用的。 # 2 安装Ingress我们通过helm来安装，会方便一些，先更新helm的仓库。 $ helm repo updateHelm相关文章：用Helm部署Kubernetes应用，支持多环境部署与版本回滚 (opens new window) 更新完之后，查找仓库关于Ingress的包有哪些： $ $ helm search repo ingress NAME CHART VERSION APP VERSION DESCRIPTION azure/gce-ingress 1.2.0 1.4.0 A GCE Ingress Controller azure/ingressmonitorcontroller 1.0.48 1.0.47 IngressMonitorController chart that runs on kub... azure/nginx-ingress 1.41.2 v0.34.1 An nginx Ingress controller that uses ConfigMap... stable/nginx-ingress 0.9.5 0.10.2 An nginx Ingress controller that uses ConfigMap... azure/contour 0.2.0 v0.15.0 Contour Ingress controller for Kubernetes azure/external-dns 1.8.0 0.5.14 Configure external DNS servers (AWS Route53, Go... azure/kong 0.36.7 1.4 DEPRECATED The Cloud-Native Ingress and API-man... azure/lamp 1.1.3 7 Modular and transparent LAMP stack chart suppor... azure/nginx-lego 0.3.1 Chart for nginx-ingress-controller and kube-lego azure/traefik 1.87.2 1.7.24 A Traefik based Kubernetes ingress controller w... azure/voyager 3.2.4 6.0.0 DEPRECATED Voyager by AppsCode - Secure Ingress... stable/external-dns 0.4.9 0.4.8 Configure external DNS servers (AWS Route53, Go... stable/lamp 0.1.4 Modular and transparent LAMP stack chart suppor... stable/nginx-lego 0.3.1 Chart for nginx-ingress-controller and kube-lego stable/traefik 1.24.1 1.5.3 A Traefik based Kubernetes ingress controller w... stable/voyager 3.1.0 6.0.0-rc.0 Voyager by AppsCode - Secure Ingress Controller...选择azure/nginx-ingress来安装，注意是有版本的。安装如下： $ helm install pkslow-ingress azure/nginx-ingress安装成功后，控制台会有输出相关的使用说明。但要注意的是，要去Kubernetes Dashboard查看一下是否真的安装成功。我安装遇到过失败，原因都是因为镜像下载失败。解决方案是打开全局代理，先手动下载好相关镜像。如： us.gcr.io/k8s-artifacts-prod/ingress-nginx/controller:v0.34.1 k8s.gcr.io/defaultbackend-amd64:1.5 jettech/kube-webhook-certgen:v1.0.0 quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.32.0之后就安装成功了，相关的Pods都跑起来了。相关的Deployment有：
一个最简单的例子如下： apiVersion: apps/v1 kind: Deployment metadata: name: nginx-deployment spec: selector: matchLabels: app: nginx replicas: 1 template: metadata: labels: app: nginx spec: containers: - name: nginx image: nginx:1.19.0 ports: - containerPort: 80 --- apiVersion: v1 kind: Service metadata: labels: app: nginx name: nginx-service spec: ports: - port: 80 name: nginx-service protocol: TCP targetPort: 80 selector: app: nginx type: ClusterIP --- apiVersion: extensions/v1beta1 kind: Ingress metadata: name: example-ingress annotations: kubernetes.io/ingress.class: nginx spec: rules: - http: paths: - path: / backend: serviceName: nginx-service servicePort: 80 host: localhost这样配置后，当我们访问http://localhost/时，就会把我们的请求转发到nginx-service的80端口上去。如下所示：
当要访问多个服务时，事情就变得复杂起来了。访问多个服务，有两种配置方式，一种是通过URL路径匹配再转发，另一种是通过子域名转发。 # 3.2.1 子域名方式通过子域名转发如下配置： apiVersion: extensions/v1beta1 kind: Ingress metadata: name: example-ingress annotations: kubernetes.io/ingress.class: nginx spec: rules: - http: paths: - path: / backend: serviceName: nginx-service servicePort: 80 host: nginx.localhost - http: paths: - path: / backend: serviceName: springboot-service servicePort: 8080 host: springboot.localhost为了节省篇幅，这里就只展示Ingress的配置了。 访问http://nginx.localhost/如下：
访问http://springboot.localhost/swagger-ui.html如下，注意这个URL带了子路径swagger-ui.html：
那通过URL路径匹配方式是不是这样配置呢？ apiVersion: extensions/v1beta1 kind: Ingress metadata: name: example-ingress annotations: kubernetes.io/ingress.class: nginx spec: rules: - http: paths: - path: /nginx backend: serviceName: nginx-service servicePort: 80 host: localhost - http: paths: - path: /springboot backend: serviceName: springboot-service servicePort: 8080 host: localhost这样配置后，会直接报404，但不是Ingress的404，而是Nginx或Springboot的404。说明请求已经成功转发到对应的service了，但路径有问题。原因是，当这样配置时，Ingress会把path也转发到service上。所以实际效果如下： localhost/nginx --> nginx-service/nginx localhost/springboot --> springboot-service/springboot使用子域名没有问题，那是因为路径是/。 解决方案一：配置rewrite，如nginx.ingress.kubernetes.io/rewrite-target: /，具体如下： apiVersion: extensions/v1beta1 kind: Ingress metadata: name: example-ingress annotations: kubernetes.io/ingress.class: nginx nginx.ingress.kubernetes.io/rewrite-target: / spec: rules: - http: paths: - path: /nginx backend: serviceName: nginx-service servicePort: 80 host: localhost - http: paths: - path: /springboot backend: serviceName: springboot-service servicePort: 8080 host: localhost这样配置后，就变成了： localhost/nginx --> nginx-service/ localhost/springboot --> springboot-service/这样似乎是解决了问题，但实际并没有，比如访问localhost/springboot可以正常访问：
但访问http://localhost/springboot/swagger-ui.html，还是转发到了/上：
解决方案二：使用正则rewrite，如下： apiVersion: extensions/v1beta1 kind: Ingress metadata: name: example-ingress annotations: kubernetes.io/ingress.class: nginx nginx.ingress.kubernetes.io/rewrite-target: /$2 spec: rules: - http: paths: - path: /nginx(/|$)(.*) backend: serviceName: nginx-service servicePort: 80 host: localhost - http: paths: - path: /springboot(/|$)(.*) backend: serviceName: springboot-service servicePort: 8080 host: localhost可正常访问带子路径了：http://localhost/springboot/swagger-ui.html#/base-controller/pkslowUsingGET
注：使用正则rewrite时，下面这样也是可以的： apiVersion: extensions/v1beta1 kind: Ingress metadata: name: example-ingress annotations: kubernetes.io/ingress.class: nginx nginx.ingress.kubernetes.io/rewrite-target: /$1 spec: rules: - http: paths: - path: /nginx/(.*) backend: serviceName: nginx-service servicePort: 80 host: localhost - http: paths: - path: /springboot/(.*) backend: serviceName: springboot-service servicePort: 8080 host: localhost除了一个小问题：http://localhost/nginx无法正常访问，要http://localhost/nginx/才可以，因为少了/会匹配不到，返回Ingress的404。 # 4 总结过了一遍，坑真不少。使用子域名感觉是比较好的方式。另外，Ingress还有一个坑，它是实现HTTP/HTTPS转发的，但TCP就不行了，比如我在Kubernetes安装了一个MySQL数据库，需要把地址和3306以TCP方式暴露给外面，就比较麻烦了，我们后续再讨论吧。 上次更新: 2023/3/19 23:54:53← 把Spring Cloud Data Flow部署在Kubernetes上，再跑个任务试试 Kubernetes备份所有集群中的资源为yaml文件 → |
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