CoreDNS无法在Kubernetes集群中运行

jvj*_*jvj 11 docker kubernetes ubuntu-16.04 coredns

我正在尝试设置Kubernetes集群,但我无法运行CoreDNS.我运行了以下命令来启动集群:

sudo swapoff -a
sudo sysctl net.bridge.bridge-nf-call-iptables=1
sudo kubeadm init

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

kubectl apply -f "https://cloud.weave.works/k8s/net?k8s- version=$(kubectl version | base64 | tr -d '\n')"
kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/master/src/deploy/recommended/kubernetes-dashboard.yaml
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为了检查POD kubectl get pods --all-namespaces,我明白了

NAMESPACE     NAME                                    READY   STATUS             RESTARTS   AGE
kube-system   coredns-68fb79bcf6-6s5bp                0/1     CrashLoopBackOff   6          10m
kube-system   coredns-68fb79bcf6-hckxq                0/1     CrashLoopBackOff   6          10m
kube-system   etcd-myserver                           1/1     Running            0          79m
kube-system   kube-apiserver-myserver                 1/1     Running            0          79m
kube-system   kube-controller-manager-myserver        1/1     Running            0          79m
kube-system   kube-proxy-9ls64                        1/1     Running            0          80m
kube-system   kube-scheduler-myserver                 1/1     Running            0          79m
kube-system   kubernetes-dashboard-77fd78f978-tqt8m   1/1     Running            0          80m
kube-system   weave-net-zmhwg                         2/2     Running            0          80m
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所以CoreDNS不断崩溃.我能找到的唯一错误消息来自 /var/log/syslog:

Oct  4 18:06:44 myserver kubelet[16397]: E1004 18:06:44.961409   16397 pod_workers.go:186] Error syncing pod c456a48b-c7c3-11e8-bf23-02426706c77f ("coredns-68fb79bcf6-6s5bp_kube-system(c456a48b-c7c3-11e8-bf23-02426706c77f)"), skipping: failed to "StartContainer" for "coredns" with CrashLoopBackOff: "Back-off 5m0s restarting failed container=coredns pod=coredns-68fb79bcf6-6s5bp_kube-system(c456a48b-c7c3-11e8-bf23-02426706c77f)"
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来自kubectl logs coredns-68fb79bcf6-6s5bp -n kube-system:

.:53
2018/10/04 11:04:55 [INFO] CoreDNS-1.2.2
2018/10/04 11:04:55 [INFO] linux/amd64, go1.11, eb51e8b
CoreDNS-1.2.2
linux/amd64, go1.11, eb51e8b
2018/10/04 11:04:55 [INFO] plugin/reload: Running configuration MD5 = f65c4821c8a9b7b5eb30fa4fbc167769
2018/10/04 11:04:55 [FATAL] plugin/loop: Seen "HINFO IN 3256902131464476443.1309143030470211725." more than twice, loop detected
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我发现的一些解决方案是要发布的

kubectl -n kube-system get deployment coredns -o yaml | \
sed 's/allowPrivilegeEscalation: false/allowPrivilegeEscalation: true/g' | \
kubectl apply -f -
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并修改/etc/resolv.conf为指向实际的DNS,而不是localhost,我也尝试过.

该问题在https://kubernetes.io/docs/setup/independent/troubleshooting-kubeadm/#pods-in-runco​​ntainererror-crashloopbackoff-or-error-state中进行了描述,我尝试了许多不同的Pod网络,但没有任何帮助.

我跑sudo kubeadm reset && rm -rf ~/.kube/ && sudo kubeadm init了好几次.

我正在运行Ubuntu 16.04,Kubernetes 1.12和Docker 17.03.有任何想法吗?

小智 18

我也有同样的问题.

我会通过删除cmred cm内的插件'loop'来解决问题.但我不知道这个云案例是否还有其他问题.

1,kubectl编辑cm coredns -n kube-system

2,删除'循环',保存并退出

3,重启coredns pods:"kubctel delete pod coredns .... -n kube-system"

  • 我尝试了这个,coredns 的 CPU 利用率非常高。删除“loop”意味着 coredns 将无法检测 dns 解析循环。不建议删除“循环”。 (4认同)
  • 这对我有用,但是我们知道为什么会起作用吗?我们是否通过删除而失去了任何东西? (2认同)

Ric*_* Li 7

使用这种方式可以解决一些问题:

  1. 打开并编辑coredns的配置图。

    kubectl edit cm coredns -n kube-system

  2. “将代理。/etc/resolv.conf替换为上游DNS的IP地址,例如代理8.8.8.8。” 根据coredns日志输出中的链接(在页面末尾)
  3. 保存并退出。
  4. kubectl get pods -n kube-system -oname | grep coredns | xargs kubectl delete -n kube-system

链接中说明了问题的原因。您可以在此cmd的输出中找到此链接

kubectl日志coredns-7d9cd4f75b-cpwxp -n kube-system

此链接在CoreDNS-1.2.4的输出中。

我使用此cmd升级CoreDNS

kubectl补丁程序部署-n = kube-system coredns -p'{“ spec”:{“ template”:{“ spec”:{“ containers”:[{“ image”:“ k8s.gcr.io/coredns:1.2。 4“,” name“:” coredns“,” resources“:{” limits“:{” memory“:” 1Gi“},” requests“:{” cpu“:” 100m“,” memory“:” 70Mi“ }}}]}}}}'


Vit*_*Vit 1

是的你是对的。该问题已在此处GitHub 上进行了描述。解决方法是升级 Docker、禁用 SElinux 或修改allowPrivilegeEscalationtrue. 但是,今天我尝试重现您的问题,但未能做到这一点。为您提供命令和输出,也许它将帮助您从一开始就创建一个工作版本。

Docker 版本 17.03.2-ce、Kubernetes v1.12.0、Ubuntu 16.04、CoreDNS-1.2.2、在 GCP 中创建的实例。

#apt-get update && apt-get install -y mc ebtables ethtool docker.io apt-transport-https curl
#curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -

#cat <<EOF >/etc/apt/sources.list.d/kubernetes.list \
deb http://apt.kubernetes.io/ kubernetes-xenial main \
EOF

#apt-get update && apt-get install -y kubelet kubeadm kubectl

#kubeadm init
$mkdir -p $HOME/.kube
$sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
$sudo chown $(id -u):$(id -g) $HOME/.kube/config
$kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')"
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已创建服务帐户/weave-net

创建 clusterrole.rbac.authorization.k8s.io/weave-net

创建 clusterrolebinding.rbac.authorization.k8s.io/weave-net

创建了 role.rbac.authorization.k8s.io/weave-net

创建了 rolebinding.rbac.authorization.k8s.io/weave-net

daemonset.extensions/weave-net 创建

$kubectl get pods --all-namespaces
NAMESPACE     NAME                                              READY   STATUS              RESTARTS   AGE
kube-system   pod/coredns-576cbf47c7-6qbtq                      0/1     Pending             0          79s
kube-system   pod/coredns-576cbf47c7-jr6hb                      0/1     Pending             0          79s
kube-system   pod/etcd-kube-weave-master-1                      1/1     Running             0          38s
kube-system   pod/kube-apiserver-kube-weave-master-1            1/1     Running             0          28s
kube-system   pod/kube-controller-manager-kube-weave-master-1   1/1     Running             0          30s
kube-system   pod/kube-proxy-4p9l5                              1/1     Running             0          79s
kube-system   pod/kube-scheduler-kube-weave-master-1            1/1     Running             0          34s
kube-system   pod/weave-net-z6mhw                               0/2     ContainerCreating   0          8s
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一分钟后再次:

$kubectl get pods --all-namespaces
NAMESPACE     NAME                                              READY   STATUS    RESTARTS   AGE
kube-system   pod/coredns-576cbf47c7-6qbtq                      1/1     Running   0          98s
kube-system   pod/coredns-576cbf47c7-jr6hb                      1/1     Running   0          98s
kube-system   pod/etcd-kube-weave-master-1                      1/1     Running   0          57s
kube-system   pod/kube-apiserver-kube-weave-master-1            1/1     Running   0          47s
kube-system   pod/kube-controller-manager-kube-weave-master-1   1/1     Running   0          49s
kube-system   pod/kube-proxy-4p9l5                              1/1     Running   0          98s
kube-system   pod/kube-scheduler-kube-weave-master-1            1/1     Running   0          53s
kube-system   pod/weave-net-z6mhw                               2/2     Running   0          27s
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Coredns pod 描述:

kubectl describe pod/coredns-576cbf47c7-6qbtq -n kube-system
Name:               coredns-576cbf47c7-6qbtq
Namespace:          kube-system
Priority:           0
PriorityClassName:  <none>
Node:               kube-weave-master-1/10.154.0.8
Start Time:         Fri, 05 Oct 2018 11:06:54 +0000
Labels:             k8s-app=kube-dns
                    pod-template-hash=576cbf47c7
Annotations:        <none>
Status:             Running
IP:                 10.32.0.3
Controlled By:      ReplicaSet/coredns-576cbf47c7
Containers:
  coredns:
    Container ID:  docker://db1712600b4c927b99063fa41bc36c3346c55572bd63730fc993f03379fa457b
    Image:         k8s.gcr.io/coredns:1.2.2
    Image ID:      docker-pullable://k8s.gcr.io/coredns@sha256:3e2be1cec87aca0b74b7668bbe8c02964a95a402e45ceb51b2252629d608d03a
    Ports:         53/UDP, 53/TCP, 9153/TCP
    Host Ports:    0/UDP, 0/TCP, 0/TCP
    Args:
      -conf
      /etc/coredns/Corefile
    State:          Running
      Started:      Fri, 05 Oct 2018 11:06:57 +0000
    Ready:          True
    Restart Count:  0
    Limits:
      memory:  170Mi
    Requests:
      cpu:        100m
      memory:     70Mi
    Liveness:     http-get http://:8080/health delay=60s timeout=5s period=10s #success=1 #failure=5
    Environment:  <none>
    Mounts:
      /etc/coredns from config-volume (ro)
      /var/run/secrets/kubernetes.io/serviceaccount from coredns-token-wp7tm (ro)
Conditions:
  Type              Status
  Initialized       True 
  Ready             True 
  ContainersReady   True 
  PodScheduled      True 
Volumes:
  config-volume:
    Type:      ConfigMap (a volume populated by a ConfigMap)
    Name:      coredns
    Optional:  false
  coredns-token-wp7tm:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  coredns-token-wp7tm
    Optional:    false
QoS Class:       Burstable
Node-Selectors:  <none>
Tolerations:     CriticalAddonsOnly
                 node-role.kubernetes.io/master:NoSchedule
                 node.kubernetes.io/not-ready:NoExecute for 300s
                 node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type     Reason            Age                 From                          Message
  ----     ------            ----                ----                          -------
  Warning  FailedScheduling  23m (x12 over 24m)  default-scheduler             0/1 nodes are available: 1 node(s) had taints that the pod didn't tolerate.
  Normal   Scheduled         23m                 default-scheduler             Successfully assigned kube-system/coredns-576cbf47c7-6qbtq to kube-weave-master-1
  Normal   Pulled            23m                 kubelet, kube-weave-master-1  Container image "k8s.gcr.io/coredns:1.2.2" already present on machine
  Normal   Created           23m                 kubelet, kube-weave-master-1  Created container
  Normal   Started           23m                 kubelet, kube-weave-master-1  Started container
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另外,请提供您config.yaml用来kubeadm init --config config.yaml更好地理解指定配置文件位置的问题。