ingress的故障排查方法

参考：

https://kubernetes.github.io/ingress-nginx/troubleshooting/

https://kubernetes.github.io/ingress-nginx/kubectl-plugin/

注意：

ingress-nginx插件在修改部署方式为daemonset后，无法使用

拓展：ingress-nginx插件

1，首先我们来看下ingress-nginx的插件输出。以bankend为例子

kubectl ingress-nginx backends -n ingress-nginx
[
  {
    "name": "default-apple-service-5678",
    "service": {
      "metadata": {
        "creationTimestamp": null
      },
      "spec": {
        "ports": [
          {
            "protocol": "TCP",
            "port": 5678,
            "targetPort": 5678
          }
        ],
        "selector": {
          "app": "apple"
        },
        "clusterIP": "10.97.230.121",
        "type": "ClusterIP",
        "sessionAffinity": "None"
      },
      "status": {
        "loadBalancer": {}
      }
    },
    "port": 0,
    "secureCACert": {
      "secret": "",
      "caFilename": "",
      "pemSha": ""
    },
    "sslPassthrough": false,
    "endpoints": [
      {
        "address": "10.1.3.86",
        "port": "5678"
      }
    ],
    "sessionAffinityConfig": {
      "name": "",
      "cookieSessionAffinity": {
        "name": ""
      }
    },
    "upstreamHashByConfig": {
      "upstream-hash-by-subset-size": 3
    },
    "noServer": false,
    "trafficShapingPolicy": {
      "weight": 0,
      "header": "",
      "headerValue": "",
      "cookie": ""
    }
  },
  {
    "name": "default-echo-service-8080",
    ...
  },
  {
    "name": "upstream-default-backend",
    ...
  }
]

2,我们看下插件目录的结构

[root@k8s-master-01.novalocal 14:41 ~/.krew]
# ls -lt
total 0
drwxr-xr-x. 2 root root  55 Jul  9 12:28 bin
drwxr-xr-x. 4 root root  39 Jul  9 12:28 store
drwxr-xr-x. 5 root root 209 Jul  9 12:28 index

• bin为命令所在目录
• store为命令软连接
• index为配置元文件

3，查看ingress-nginx配置

apiVersion: krew.googlecontainertools.github.com/v1alpha2
kind: Plugin
metadata:
  name: ingress-nginx
spec:
  shortDescription: Interact with ingress-nginx
  description: |
    The official kubectl plugin for ingress-nginx.
  version: 0.24.0
  homepage: https://kubernetes.github.io/ingress-nginx/kubectl-plugin/
  platforms:
  - uri: https://github.com/kubernetes/ingress-nginx/releases/download/nginx-0.24.0/kubectl-ingress_nginx-darwin-amd64.tar.gz
    sha256: 34e999ddc4e1926bbd7f4bdbb5fc40d6c3a5b2ffd711131e4f62e2d24cb2a179
    files:
    - from: "*"
      to: "."
    bin: "./kubectl-ingress_nginx"
    selector:
      matchLabels:
        os: darwin
        arch: amd64
  - uri: https://github.com/kubernetes/ingress-nginx/releases/download/nginx-0.24.0/kubectl-ingress_nginx-linux-amd64.tar.gz
    sha256: 05d48fe58faa0ff577fe3b9c90f2e21233a140712a9f9ff0c9bd867e65f1b4e5
    files:
    - from: "*"
      to: "."
    bin: "./kubectl-ingress_nginx"
    selector:
      matchLabels:
        os: linux
        arch: amd64

4,查看命令源码

在cmd/plugin/main.go
rootCmd.AddCommand(backends.CreateCommand(flags))

查看具体的backends。实际 是登录到pod中然后执行了相关的命令

在cmd/plugin/commands/backends/backends.go

func backends(flags *genericclioptions.ConfigFlags, podName string, deployment string, backend string, onlyList bool) error {
    var command []string
    if onlyList {
        command = []string{"/dbg", "backends", "list"}
    } else if backend != "" {
        command = []string{"/dbg", "backends", "get", backend}
    } else {
        command = []string{"/dbg", "backends", "all"}
    }

    pod, err := request.ChoosePod(flags, podName, deployment)
    if err != nil {
        return err
    }

    out, err := kubectl.PodExecString(flags, &pod, command)
    if err != nil {
        return err
    }

    fmt.Print(out)
    return nil
}

执行命令可能为

• /dbg backends list
• /dbg backends get xxx
• /dbg backends all