问题
I am trying to configure a 2 node Kubernetes cluster. First I am trying to configure the master node of the cluster on a CentOS VM. I have initialized the cluster using 'kubeadm init --apiserver-advertise-address=172.16.100.6 --pod-network-cidr=10.244.0.0/16' and deployed the flannel network to the cluster. But when I do 'kubectl get nodes', I get the following output ----
[root@kubernetus ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
kubernetus NotReady master 57m v1.12.0
Following is the output of 'kubectl get pods --all-namespaces -o wide ' ----
[root@kubernetus ~]# kubectl get pods --all-namespaces -o wide
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
kube-system coredns-576cbf47c7-9x59x 0/1 Pending 0 58m <none> <none> <none>
kube-system coredns-576cbf47c7-l52wc 0/1 Pending 0 58m <none> <none> <none>
kube-system etcd-kubernetus 1/1 Running 2 57m 172.16.100.6 kubernetus <none>
kube-system kube-apiserver-kubernetus 1/1 Running 2 57m 172.16.100.6 kubernetus <none>
kube-system kube-controller-manager-kubernetus 1/1 Running 1 57m 172.16.100.6 kubernetus <none>
kube-system kube-proxy-hr557 1/1 Running 1 58m 172.16.100.6 kubernetus <none>
kube-system kube-scheduler-kubernetus 1/1 Running 1 57m 172.16.100.6 kubernetus <none>
coredns is in a pending state for a very long time. I have removed docker and kubectl, kubeadm, kubelet a no of times & tried to recreate the cluster, but every time it shows the same output. Can anybody help me with this issue?
回答1:
Unable to update cni config: No networks found in /etc/cni/net.d ..... Oct 02 19:21:32 kubernetus kubelet[19007]: E1002 19:21:32.886170 19007 kubelet.go:2167] Container runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: cni config uninitialized
According to this error, you forgot to initialize a Kubernetes Pod network add-on. Looking at your settings, I suppose it should be Flannel.
Here is the instruction from the official Kubernetes documentation:
For flannel to work correctly, you must pass
--pod-network-cidr=10.244.0.0/16to kubeadm init.Set
/proc/sys/net/bridge/bridge-nf-call-iptablesto 1 by runningsysctl net.bridge.bridge-nf-call-iptables=1to pass bridged IPv4 traffic to iptables’ chains. This is a requirement for some CNI plugins to work, for more information please see here.kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/v0.10.0/Documentation/kube-flannel.ymlNote that flannel works on amd64, arm, arm64 and ppc64le, but until flannel v0.11.0 is released you need to use the following manifest that supports all the architectures:
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/c5d10c8/Documentation/kube-flannel.yml
For more information, you can visit this link.
回答2:
Try to install Pod network add-on (Base on this guide).
Run this line:
kubectl apply -f https://docs.projectcalico.org/v3.14/manifests/calico.yaml
回答3:
Check if docker and kubernetes are using the same cgroup driver. I faced the same issue (CentOS 7, kubernetes v1.14.1), and setting same cgroup driver (systemd) fixed it.
回答4:
For the Kubernetes cluster to be available, the cluster should have a Container Networking Interface (CNI). A pod-network is required to be configured for the dns pod to be functional.
Install any of the CNI Providers like: - Flannel - Calico - Canal - WeaveNet, etc.,
Without this, the hosted Kubernetes cluster would have the master in the NotReady State.
回答5:
I installed kubernetes with 1 master + 1 work-node.
After I made kubeadm init ..., I faced two issues:
- On the master node, the coredns were pending.
- On the work-node, kubectl command didn't work out
On the work-node, I did the following and fixed the both issues:
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/kubelet.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config**
来源：https://stackoverflow.com/questions/52609257/coredns-in-pending-state-in-kubernetes-cluster