kubernetes - 无法 nslookup kubernetes.default

Question

我在 Ubuntu 16.04 上运行了 kubernetes 集群。当我在 master 上运行 nslookup kubernetes.default 时，它显示如下:

Server:     192.168.88.21
Address:    192.168.88.21#53

** server can't find kubernetes.default: NXDOMAIN

下面是/etc/resolv.conf的内容

# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN

nameserver 192.168.88.21
nameserver 127.0.1.1
search VISDWK.local

使用kubernetes版本

kubeadm version: &version.Info{Major:"1", Minor:"13", GitVersion:"v1.13.1", GitCommit:"eec55b9ba98609a46fee712359c7b5b365bdd920", GitTreeState:"clean", BuildDate:"2018-12-13T10:36:44Z", GoVersion:"go1.11.2", Compiler:"gc", Platform:"linux/amd64"}

使用 weave 进行联网并使用以下方式安装:

kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')"

coredns pod 运行良好:

coredns-86c58d9df4-42xqc               1/1     Running   8         1d6h
coredns-86c58d9df4-p6d98               1/1     Running   7         1d1h

下面是coredns-86c58d9df4-42xqc的日志

.:53
2019-02-08T08:40:10.038Z [信息] CoreDNS-1.2.6
2019-02-08T08:40:10.039Z [信息] linux/amd64, go1.11.2, 756749c
CoreDNS-1.2.6
linux/amd64, go1.11.2, 756749c
[信息] 插件/重新加载:运行配置 MD5 = f65c4821c8a9b7b5eb30fa4fbc167769
t

任何人都可以帮我调试这个问题。请帮忙。谢谢。

Answer 1

busybox 图像有问题。它可以工作，但在运行 nslookup 命令后出现一些错误

[node1 ~]$ kubectl run busybox1 --image busybox --restart=Never --rm -it -- sh
If you don't see a command prompt, try pressing enter.
/ # nslookup kubernetes
Server:         10.96.0.10
Address:        10.96.0.10:53

Name:   kubernetes.default.svc.cluster.local
Address: 10.96.0.1

*** Can't find kubernetes.svc.cluster.local: No answer
*** Can't find kubernetes.cluster.local: No answer
*** Can't find kubernetes.default.svc.cluster.local: No answer
*** Can't find kubernetes.svc.cluster.local: No answer
*** Can't find kubernetes.cluster.local: No answer
/ # exit
pod "busybox1" deleted
[node1 ~]$

尝试下图。它工作得很好。其他版本抛出一些错误

busybox:1.28

[node1 ~]$ kubectl run busybox1 --image busybox:1.28 --restart=Never --rm -it -- sh
If you don't see a command prompt, try pressing enter.
/ # nslookup kubernetes
Server:    10.96.0.10
Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local

Name:      kubernetes
Address 1: 10.96.0.1 kubernetes.default.svc.cluster.local
/ # exit
pod "busybox1" deleted

从 master 测试 api 服务器

[node1 ~]$ kubectl get svc|grep kubernetes
kubernetes      ClusterIP      10.96.0.1      <none>        443/TCP          2h
[node1 ~]$
[node1 ~]$ curl -k https://10.96.0.1/version
{
  "major": "1",
  "minor": "11",
  "gitVersion": "v1.11.7",
  "gitCommit": "65ecaf0671341311ce6aea0edab46ee69f65d59e",
  "gitTreeState": "clean",
  "buildDate": "2019-01-24T19:22:45Z",
  "goVersion": "go1.10.7",
  "compiler": "gc",
  "platform": "linux/amd64"
}[node1 ~]$