Kubernetes使用Nginx Ingress暴露Dashboard

超、凢脫俗 2022-05-11 06:28 195阅读 0赞

# Kubernetes使用Nginx Ingress暴露Dashboard #

### 文章目录 ###

*  Kubernetes使用Nginx Ingress暴露Dashboard
 *   *  1. 环境说明
     *  2. 成功要点
     *  3. 为什么
     *  4. 小结

## 1. 环境说明 ##

*  可用的kubernetes集群
 *  可用的nginx ingress controller
 *  可用的dashboard

关于kubernetes、dashboard和nginx ingress在前面文章中，已有介绍。  
《centos7使用kubeadm安装kubernetes 1.11版本多主高可用》  
《kubernetes 1.11配置使用nginx ingress》  
也可以使用helm快速搭建nginx ingress和dashboard。  
`stable/kubernetes-dashboard`  
`stable/nginx-ingress`

## 2. 成功要点 ##

ingress配置啥的这里不详细介绍 。关于暴露dashboard成功的关键，在于新版本dashboard默认使用**https**提供服务。所以，在ingress中要配置如下`annotations`参数。

apiVersion: extensions/v1beta1
    kind: Ingress
    metadata:
      annotations:
        nginx.ingress.kubernetes.io/ingress.class: nginx
        nginx.ingress.kubernetes.io/secure-backends: "true"
        nginx.ingress.kubernetes.io/ssl-passthrough: "true"

## 3. 为什么 ##

而为什么是这个`nginx.ingress.kubernetes.io`前缀呢？

来查查nginx ingress的service，是不是有这个`metadata`：

[root@lab1 gitlab]# kubectl get svc -n nginx-ingress 
    NAME                            TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)                   AGE
    nginx-ingress-controller        ClusterIP   10.105.201.166   <none>        80/TCP,443/TCP,2222/TCP   23h
    nginx-ingress-default-backend   ClusterIP   10.110.35.3      <none>        80/TCP                    23h
    [root@lab1 gitlab]# kubectl get svc -n nginx-ingress  nginx-ingress-controller  -o yaml
    apiVersion: v1
    kind: Service
    metadata:
      creationTimestamp: 2018-09-19T09:54:51Z
      labels:
        app: nginx-ingress
        chart: nginx-ingress-0.9.5
        component: controller
        heritage: Tiller
        release: nginx-ingress
      name: nginx-ingress-controller
      namespace: nginx-ingress

那我们想当然的尝试加上`kubernetes.io/ingress.class: nginx`

[root@lab1 gitlab]# kubectl edit svc -n nginx-ingress  nginx-ingress-controller 
    # Please edit the object below. Lines beginning with a '#' will be ignored,
    # and an empty file will abort the edit. If an error occurs while saving this file will be
    # reopened with the relevant failures.
    #
    apiVersion: v1
    kind: Service
    metadata:
      annotations:
        kubernetes.io/ingress.class: nginx

再去dashboard的ingress配置修改成这个：

[root@lab1 templates]# kubectl get ing -n kube-system
    NAME                             HOSTS             ADDRESS   PORTS     AGE
    dashboard-kubernetes-dashboard   k8s.linuxba.com             80, 443   48m
    [root@lab1 templates]# kubectl edit ing -n kube-system dashboard-kubernetes-dashboard
    # Please edit the object below. Lines beginning with a '#' will be ignored,
    # and an empty file will abort the edit. If an error occurs while saving this file will be
    # reopened with the relevant failures.
    #
    apiVersion: extensions/v1beta1
    kind: Ingress
    metadata:
      annotations:
        kubernetes.io/ingress.class: nginx
        kubernetes.io/secure-backends: "true"
        kubernetes.io/ssl-passthrough: "true"

然后发现，dashboard访问不了了，说明`annotations`没有生效。那看来`service`这里的`annotations`不是决定性因素。

那我们来分析下，最后生效的是nginx-ingress-controller里的程序解析的，那试试查他的程序运行命令或者帮助：

[root@lab4 ~]# find /var/lib/docker -name nginx-ingress-controller
    /var/lib/docker/overlay2/2744ab879932e0ebc522a5f2bdc78ab51742c88d13d1ba99fb1fa8601a07ea43/diff/nginx-ingress-controller
    /var/lib/docker/overlay2/63d22e69065b1e49beb4ac91e91106c8e4bab204afc9912304204619cbe7e443/diff/nginx-ingress-controller
    ^C
    [root@lab4 ~]# /var/lib/docker/overlay2/2744ab879932e0ebc522a5f2bdc78ab51742c88d13d1ba99fb1fa8601a07ea43/diff/nginx-ingress-controller --help|more
    Usage of :
          --alsologtostderr                   log to standard error as well as files
          --annotations-prefix string         Prefix of the Ingress annotations specific to the NGINX controller. (default "nginx.ingress.kubernetes.io")

果然发现了决定性参数`--annotations-prefix`。

## 4. 小结 ##

原来一直以来，我忽视掉了这个关键参数。当然，有人会说，像linux一样，用到那么多命令，那么多参数，怎么可能记得住，都看过。所以，我觉得一项很重要的习惯或者技能，是学会去摸索，去实践排查，这样我们会的东西，其实比表面看起来要多得多。

参考资料：  
\[1\] [https://kubernetes.io/docs/concepts/overview/working-with-objects/annotations/][https_kubernetes.io_docs_concepts_overview_working-with-objects_annotations]

[https_kubernetes.io_docs_concepts_overview_working-with-objects_annotations]: https://kubernetes.io/docs/concepts/overview/working-with-objects/annotations/