#Kubernetes#

#kubectl#

#Ingress#

使用场景

现在使用Kubernetes的时候，有很多UI工具可以选择，降低我们日常的使用难度，但还是有些场景，必须要使用命令行去查看，今天我们介绍的ingress-nginx插件，就可以在一些必须使用命令行的场景帮助我们提高效率

使用方法

用下面的命令安装后就可以直接使用了

kubectl krew install ingress-nginx

然后这个插件提供了很多的子命令，我们本篇文章挑一些常用来介绍：

mian@mian-PC:~$ kubectl ingress-nginx -h
A kubectl plugin for inspecting your ingress-nginx deployments
Usage:
  ingress-nginx [command]
Available Commands:
  backends    Inspect the dynamic backend information of an ingress-nginx instance
  certs       Output the certificate data stored in an ingress-nginx pod
  conf        Inspect the generated nginx.conf
  exec        Execute a command inside an ingress-nginx pod
  general     Inspect the other dynamic ingress-nginx information
  help        Help about any command
  info        Show information about the ingress-nginx service
  ingresses   Provide a short summary of all of the ingress definitions
  lint        Inspect kubernetes resources for possible issues
  logs        Get the kubernetes logs for an ingress-nginx pod
  ssh         ssh into a running ingress-nginx pod
Flags:
      --as string                      Username to impersonate for the operation
      --as-group stringArray           Group to impersonate for the operation, this flag can be repeated to specify multiple groups.
      --cache-dir string               Default HTTP cache directory (default "/home/mian/.kube/http-cache")
      --certificate-authority string   Path to a cert file for the certificate authority
      --client-certificate string      Path to a client certificate file for TLS
      --client-key string              Path to a client key file for TLS
      --cluster string                 The name of the kubeconfig cluster to use
      --context string                 The name of the kubeconfig context to use
  -h, --help                           help for ingress-nginx
      --insecure-skip-tls-verify       If true, the server's certificate will not be checked for validity. This will make your HTTPS connections insecure
      --kubeconfig string              Path to the kubeconfig file to use for CLI requests.
  -n, --namespace string               If present, the namespace scope for this CLI request
      --request-timeout string         The length of time to wait before giving up on a single server request. Non-zero values should contain a corresponding time unit (e.g. 1s, 2m, 3h). A value of zero means don't timeout requests. (default "0")
  -s, --server string                  The address and port of the Kubernetes API server
      --tls-server-name string         Server name to use for server certificate validation. If it is not provided, the hostname used to contact the server is used
      --token string                   Bearer token for authentication to the API server
      --user string                    The name of the kubeconfig user to use
Use "ingress-nginx [command] --help" for more information about a command.

• ingresses

之前我们看ingress是这样：

$ kubectl get ingresses --all-namespaces
NAMESPACE   NAME               HOSTS                            ADDRESS     PORTS   AGE
default     example-ingress1   testaddr.local,testaddr2.local   localhost   80      5d
default     test-ingress-2     *                                localhost   80      5d

有了这个插件后，输出会更丰富一些，包含了指向的service和后端副本数

$ kubectl ingress-nginx ingresses --all-namespaces
NAMESPACE   INGRESS NAME       HOST+PATH                        ADDRESSES   TLS   SERVICE         SERVICE PORT   ENDPOINTS
default     example-ingress1   testaddr.local/etameta           localhost   NO    pear-service    5678           5
default     example-ingress1   testaddr2.local/otherpath        localhost   NO    apple-service   5678           1
default     example-ingress1   testaddr2.local/otherotherpath   localhost   NO    pear-service    5678           5
default     test-ingress-2     *                                localhost   NO    echo-service    8080           2

• conf

有时候我们下发了配置效果不符合预期，通常会去检查最终生成的nginx配置文件，要进入到ingress controller去查看，有了conf命令就简单多了：

kubectl ingress-nginx conf -n ingress-nginx --host testaddr.local

    server {
        server_name testaddr.local ;

        listen 80;

        set $proxy_upstream_name "-";
        set $pass_access_scheme $scheme;
        set $pass_server_port $server_port;
        set $best_http_host $http_host;
        set $pass_port $pass_server_port;

        location / {

            set $namespace      "";
            set $ingress_name   "";
            set $service_name   "";
            set $service_port   "0";
            set $location_path  "/";

...

• lint

这个命令可以帮助我们检查ingress规范的版本不兼容的地方，尤其在升级版本之前检查下，非常有用：非常有用

$ kubectl ingress-nginx lint --all-namespaces --verbose
Checking ingresses...
? anamespace/this-nginx
  - Contains the removed session-cookie-hash annotation.
       Lint added for version 0.24.0
       https://github.com/kubernetes/ingress-nginx/issues/3743
? othernamespace/ingress-definition-blah
  - The rewrite-target annotation value does not reference a capture group
      Lint added for version 0.22.0
      https://github.com/kubernetes/ingress-nginx/issues/3174

Checking deployments...
? namespace2/nginx-ingress-controller
  - Uses removed config flag --sort-backends
      Lint added for version 0.22.0
      https://github.com/kubernetes/ingress-nginx/issues/3655
  - Uses removed config flag --enable-dynamic-certificates
      Lint added for version 0.24.0
      https://github.com/kubernetes/ingress-nginx/issues/3808

还有几点要注意的地方：

1. 命名空间的指定一定要放在ingress-nginx插件命令之后，否则kubectl识别会有误
2. 如果ingress controller的deployment不是叫“ingress-nginx-controller”，就需要手动指定名称