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吊舱中缺少SkyDNS群集DNS

dns kubernetes

吊舱中缺少SkyDNS群集DNS,dns,kubernetes,skydns,kubernetes-health-check,Dns,Kubernetes,Skydns,Kubernetes Health Check,我在3台REHEL7服务器上安装了kubernetes 1.2.4（没有互联网接入，一切都由ansible推动） 编辑：请参见问题的结尾 除了文档中给出的kube dns示例之外，我的一切都很好。我做了几次测试，几次配置，重建了整个吊舱。。。我总是有这样一个“MissingClusterDNS”错误： 如您所见，kube dns正在运行： kubectl get svc kube-dns --namespace=kube-system NAME CLUSTER-IP EXTE

我在3台REHEL7服务器上安装了kubernetes 1.2.4（没有互联网接入，一切都由ansible推动）

编辑：请参见问题的结尾

除了文档中给出的kube dns示例之外，我的一切都很好。我做了几次测试，几次配置，重建了整个吊舱。。。我总是有这样一个“MissingClusterDNS”错误：

如您所见，kube dns正在运行：

kubectl get svc kube-dns --namespace=kube-system
NAME       CLUSTER-IP     EXTERNAL-IP   PORT(S)         AGE
kube-dns   172.16.0.99   <none>        53/UDP,53/TCP   15m
证明：

ps ax | grep kubelet
 6077 ?        Ssl    0:07 /opt/kubernetes/bin/kubelet --logtostderr=true --v=0 --address=0.0.0.0 --port=10250 --hostname-override=k8s-minion-1.XXXXXX --api-servers=http://k8s-master.XXXXXX:8080 --allow-privileged=false  --cluster-dns=172.16.0.99 --cluster-domain=kubernetes.local
但是，DNS吊舱作为未运行的容器：

kubectl get pods  --namespace=kube-system
NAME                 READY     STATUS             RESTARTS   AGE
kube-dns-v11-f2f4a   3/4       CrashLoopBackOff   7          18m
并且日志是明确的：

Warning Unhealthy   Readiness probe failed: Get http://172.16.23.2:8081/readiness: dial tcp 172.16.23.2:8081: connection refused
...
Warning FailedSync  Error syncing pod, skipping: failed to "StartContainer" for "kube2sky" with CrashLoopBackOff: "Back-off 5m0s restarting failed container=kube2sky pod=kube-dns-v11-f2f4a_kube-system(27d70b7c-36f9-11e6-b4fe-fa163ee85c45)"
如果您需要更多信息：

$ kubectl get pods  --namespace=kube-system
NAME                 READY     STATUS             RESTARTS   AGE
kube-dns-v11-f2f4a   3/4       CrashLoopBackOff   7          18m

-------------------------  

$ kubectl describe rc  --namespace=kube-system
Name:       kube-dns-v11
Namespace:  kube-system
Image(s):   our.registry/gcr.io/google_containers/etcd-amd64:2.2.1,our.registry/gcr.io/google_containers/kube2sky:1.14,our.registry/gcr.io/google_containers/skydns:2015-10-13-8c72f8c,our.registry/gcr.io/google_containers/exechealthz:1.0
Selector:   k8s-app=kube-dns,version=v11
Labels:     k8s-app=kube-dns,kubernetes.io/cluster-service=true,version=v11
Replicas:   1 current / 1 desired
Pods Status:    1 Running / 0 Waiting / 0 Succeeded / 0 Failed
Volumes:
  etcd-storage:
    Type:   EmptyDir (a temporary directory that shares a pod's lifetime)
    Medium: 
Events:
  FirstSeen LastSeen    Count   From                SubobjectPath   Type        Reason          Message
  --------- --------    -----   ----                -------------   --------    ------          -------
  19m       19m     1   {replication-controller }           Normal      SuccessfulCreate    Created pod: kube-dns-v11-f2f4a

-------------------------------------------------------

$ kubectl get all --all-namespaces 
NAMESPACE     NAME                 DESIRED        CURRENT            AGE
kube-system   kube-dns-v11         1              1                  24m
NAMESPACE     NAME                 CLUSTER-IP     EXTERNAL-IP        PORT(S)         AGE
default       kubernetes           172.16.0.1     <none>             443/TCP         27m
kube-system   kube-dns             172.16.0.99   <none>             53/UDP,53/TCP   24m
NAMESPACE     NAME                 READY          STATUS             RESTARTS        AGE
default       busybox              1/1            Running            0               23m
kube-system   kube-dns-v11-f2f4a   3/4            CrashLoopBackOff   9               24m
使用群集api测试仪：

kubectl logs --tail=80 kube-dns-v11-c96d5 kube2sky --namespace=kube-system
I0621 13:27:52.070730       1 kube2sky.go:462] Etcd server found: http://127.0.0.1:4001
I0621 13:27:53.073614       1 kube2sky.go:529] Using https://192.168.0.1:443 for kubernetes master
I0621 13:27:53.073632       1 kube2sky.go:530] Using kubernetes API <nil>
I0621 13:27:53.074020       1 kube2sky.go:598] Waiting for service: default/kubernetes
I0621 13:27:53.166188       1 kube2sky.go:660] Successfully added DNS record for Kubernetes service.

kubectl日志——tail=80 kube-dns-v11-c96d5 kube2sky——namespace=kube系统
I0621 13:27:52.070730 1 kube2sky.go:462]Etcd服务器已找到：http://127.0.0.1:4001
I0621 13:27:53.073614 1 kube2sky.go:529]使用https://192.168.0.1:443 库伯内特斯大师
I0621 13:27:53.073632 1 kube2sky.go:530]使用kubernetes API
I0621 13:27:53.0740201 kube2sky.go:598]等待服务：默认值/kubernetes
I0621 13:27:53.166188 1 kube2sky.go:660]已成功添加Kubernetes服务的DNS记录。
但也出现了其他问题

  • 现在“使用kubernetes API nil”而不是好的版本
  • kubernetes文档中的busybox示例仍然无法解析kubernetes.local
我会进一步调查。但我解决了skydns启动问题。谢谢

您的一个DNS容器尚未准备好。这就是“就绪3/4”的意思

最好的办法是使用
kubectl logs
命令获取失败容器的日志。如果需要从已经失败的容器中获取日志，可以添加
kubectl日志--previous…

希望这将为您提供必要的信息，以调试为什么该容器没有出现。

这正是我今天早上开始尝试的内容。我正在尝试更改证书、ipv4配置等。。。此时：命中主ip时出错。就好像pod无法联系api服务器一样。谢谢。我可以接受这个答案，因为它为我提供了获得第一个问题的信息，即kube2sky问题。我需要在节中使用IP创建证书。使用cluster api tester映像，我现在看到了正确的配置。但是，busybox示例此时不起作用。。。如果我真的找不到任何信息，我会在几个小时内打开另一个主题 
$ kubectl get pods  --namespace=kube-system
NAME                 READY     STATUS             RESTARTS   AGE
kube-dns-v11-f2f4a   3/4       CrashLoopBackOff   7          18m

-------------------------  

$ kubectl describe rc  --namespace=kube-system
Name:       kube-dns-v11
Namespace:  kube-system
Image(s):   our.registry/gcr.io/google_containers/etcd-amd64:2.2.1,our.registry/gcr.io/google_containers/kube2sky:1.14,our.registry/gcr.io/google_containers/skydns:2015-10-13-8c72f8c,our.registry/gcr.io/google_containers/exechealthz:1.0
Selector:   k8s-app=kube-dns,version=v11
Labels:     k8s-app=kube-dns,kubernetes.io/cluster-service=true,version=v11
Replicas:   1 current / 1 desired
Pods Status:    1 Running / 0 Waiting / 0 Succeeded / 0 Failed
Volumes:
  etcd-storage:
    Type:   EmptyDir (a temporary directory that shares a pod's lifetime)
    Medium: 
Events:
  FirstSeen LastSeen    Count   From                SubobjectPath   Type        Reason          Message
  --------- --------    -----   ----                -------------   --------    ------          -------
  19m       19m     1   {replication-controller }           Normal      SuccessfulCreate    Created pod: kube-dns-v11-f2f4a

-------------------------------------------------------

$ kubectl get all --all-namespaces 
NAMESPACE     NAME                 DESIRED        CURRENT            AGE
kube-system   kube-dns-v11         1              1                  24m
NAMESPACE     NAME                 CLUSTER-IP     EXTERNAL-IP        PORT(S)         AGE
default       kubernetes           172.16.0.1     <none>             443/TCP         27m
kube-system   kube-dns             172.16.0.99   <none>             53/UDP,53/TCP   24m
NAMESPACE     NAME                 READY          STATUS             RESTARTS        AGE
default       busybox              1/1            Running            0               23m
kube-system   kube-dns-v11-f2f4a   3/4            CrashLoopBackOff   9               24m

NAME                 READY          STATUS        RESTARTS        AGE
kube-dns-v11-c96d5   4/4            Running       0               9m

kubectl logs --tail=80 kube-dns-v11-c96d5 kube2sky --namespace=kube-system
I0621 13:27:52.070730       1 kube2sky.go:462] Etcd server found: http://127.0.0.1:4001
I0621 13:27:53.073614       1 kube2sky.go:529] Using https://192.168.0.1:443 for kubernetes master
I0621 13:27:53.073632       1 kube2sky.go:530] Using kubernetes API <nil>
I0621 13:27:53.074020       1 kube2sky.go:598] Waiting for service: default/kubernetes
I0621 13:27:53.166188       1 kube2sky.go:660] Successfully added DNS record for Kubernetes service.