I'm trying to setup a Kubernetes cluster, but I cannot get CoreDNS running. I've ran the following to start the cluster:
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
To check the PODs with kubectl get pods --all-namespaces
, I get
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
So CoreDNS keeps crashing. The only error messages I could found were from
/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)"
and from 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
Some solutions I found are to issue
kubectl -n kube-system get deployment coredns -o yaml | \
sed 's/allowPrivilegeEscalation: false/allowPrivilegeEscalation: true/g' | \
kubectl apply -f -
and to modify /etc/resolv.conf
to point to an actual DNS, not to localhost, which I tried as well.
The issue is described in https://kubernetes.io/docs/setup/independent/troubleshooting-kubeadm/#pods-in-runcontainererror-crashloopbackoff-or-error-state and I tried many different Pod Networks but no help.
I've run sudo kubeadm reset && rm -rf ~/.kube/ && sudo kubeadm init
several times.
I'm running Ubuntu 16.04, Kubernetes 1.12 and Docker 17.03. Any ideas?
About CoreDNS Like Kubernetes, the CoreDNS project is hosted by the CNCF. You can use CoreDNS instead of kube-dns in your cluster by replacing kube-dns in an existing deployment, or by using tools like kubeadm that will deploy and upgrade the cluster for you.
I also have the same issue.
I've solved the problem by deleting the plugins 'loop' within the cm of coredns. but i don't know if this cloud case other porblems.
1、kubectl edit cm coredns -n kube-system
2、delete ‘loop’ ,save and exit
3、restart coredns pods by:kubectl delete pod coredns.... -n kube-system
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With