Xtykutl

I just installed Kubernetes on a cluster of Ubuntu's using the explanation of digital ocean with Ansible. Everything seems to be fine; but when verifying the cluster, the master node is in a not ready status:

# kubectl get nodes

NAME                STATUS     ROLES    AGE   VERSION

jwdkube-master-01   NotReady   master   44m   v1.12.2

jwdkube-worker-01   Ready      <none>   44m   v1.12.2

jwdkube-worker-02   Ready      <none>   44m   v1.12.2

This is the version:

# kubectl version

Client Version: version.Info{Major:"1", Minor:"12", GitVersion:"v1.12.2", GitCommit:"17c77c7898218073f14c8d573582e8d2313dc740", GitTreeState:"clean", BuildDate:"2018-10-24T06:54:59Z", GoVersion:"go1.10.4", Compiler:"gc", Platform:"linux/amd64"}

Server Version: version.Info{Major:"1", Minor:"12", GitVersion:"v1.12.2", GitCommit:"17c77c7898218073f14c8d573582e8d2313dc740", GitTreeState:"clean", BuildDate:"2018-10-24T06:43:59Z", GoVersion:"go1.10.4", Compiler:"gc", Platform:"linux/amd64"}

When I check the master node, the kube-proxy is hanging in a starting mode:

# kubectl describe nodes jwdkube-master-01

Name:               jwdkube-master-01

Roles:              master

...

LastTransitionTime                Reason                       Message

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

OutOfDisk        False   Thu, 08 Nov 2018 10:24:45 +0000   Thu, 08 Nov 2018 09:36:10 +0000   KubeletHasSufficientDisk     kubelet has sufficient disk space available

MemoryPressure   False   Thu, 08 Nov 2018 10:24:45 +0000   Thu, 08 Nov 2018 09:36:10 +0000   KubeletHasSufficientMemory   kubelet has sufficient memory available

DiskPressure     False   Thu, 08 Nov 2018 10:24:45 +0000   Thu, 08 Nov 2018 09:36:10 +0000   KubeletHasNoDiskPressure     kubelet has no disk pressure

PIDPressure      False   Thu, 08 Nov 2018 10:24:45 +0000   Thu, 08 Nov 2018 09:36:10 +0000   KubeletHasSufficientPID      kubelet has sufficient PID available

Ready            False   Thu, 08 Nov 2018 10:24:45 +0000   Thu, 08 Nov 2018 09:36:10 +0000   KubeletNotReady              runtime network not ready: NetworkReady=false reason:NetworkPluginNotReady message:docker: network plugin is not ready: cni config uninitialized

Addresses:

InternalIP:  104.248.207.107

Hostname:    jwdkube-master-01

Capacity:

cpu:                1

ephemeral-storage:  25226960Ki

hugepages-1Gi:      0

hugepages-2Mi:      0

memory:             1008972Ki

pods:               110

Allocatable:

cpu:                1

ephemeral-storage:  23249166298

hugepages-1Gi:      0

hugepages-2Mi:      0

memory:             906572Ki

pods:               110

System Info:

Machine ID:                 771c0f669c0a40a1ba7c28bf1f05a637

System UUID:                771c0f66-9c0a-40a1-ba7c-28bf1f05a637

Boot ID:                    2532ae4d-c08c-45d8-b94c-6e88912ed627

Kernel Version:             4.18.0-10-generic

OS Image:                   Ubuntu 18.10

Operating System:           linux

Architecture:               amd64

Container Runtime Version:  docker://18.6.1

Kubelet Version:            v1.12.2

Kube-Proxy Version:         v1.12.2

PodCIDR:                     10.244.0.0/24

Non-terminated Pods:         (5 in total)

Namespace                  Name                                         CPU Requests  CPU Limits  Memory Requests  Memory Limits

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

kube-system                etcd-jwdkube-master-01                       0 (0%)        0 (0%)      0 (0%)           0 (0%)

kube-system                kube-apiserver-jwdkube-master-01             250m (25%)    0 (0%)      0 (0%)           0 (0%)

kube-system                kube-controller-manager-jwdkube-master-01    200m (20%)    0 (0%)      0 (0%)           0 (0%)

kube-system                kube-proxy-p8cbq                             0 (0%)        0 (0%)      0 (0%)           0 (0%)

kube-system                kube-scheduler-jwdkube-master-01             100m (10%)    0 (0%)      0 (0%)           0 (0%)

Allocated resources:

(Total limits may be over 100 percent, i.e., overcommitted.)

Resource  Requests    Limits

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

cpu       550m (55%)  0 (0%)

memory    0 (0%)      0 (0%)

Events:

Type    Reason                   Age                From                           Message

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

Normal  NodeHasSufficientDisk    48m (x6 over 48m)  kubelet, jwdkube-master-01     Node jwdkube-master-01 status is now: NodeHasSufficientDisk

Normal  NodeHasSufficientMemory  48m (x6 over 48m)  kubelet, jwdkube-master-01     Node jwdkube-master-01 status is now: NodeHasSufficientMemory

Normal  NodeHasNoDiskPressure    48m (x6 over 48m)  kubelet, jwdkube-master-01     Node jwdkube-master-01 status is now: NodeHasNoDiskPressure

Normal  NodeHasSufficientPID     48m (x5 over 48m)  kubelet, jwdkube-master-01     Node jwdkube-master-01 status is now: NodeHasSufficientPID

Normal  NodeAllocatableEnforced  48m                kubelet, jwdkube-master-01     Updated Node Allocatable limit across pods

Normal  Starting                 48m                kube-proxy, jwdkube-master-01  Starting kube-proxy.

update

running kubectl get pods -n kube-system:

NAME                                        READY   STATUS    RESTARTS   AGE

coredns-576cbf47c7-8p7k2                    1/1     Running   0          4h47m

coredns-576cbf47c7-s5tlv                    1/1     Running   0          4h47m

etcd-jwdkube-master-01                      1/1     Running   1          140m

kube-apiserver-jwdkube-master-01            1/1     Running   1          140m

kube-controller-manager-jwdkube-master-01   1/1     Running   1          140m

kube-flannel-ds-5bzrx                       1/1     Running   0          4h47m

kube-flannel-ds-bfs9k                       1/1     Running   0          4h47m

kube-proxy-4lrzw                            1/1     Running   1          4h47m

kube-proxy-57x28                            1/1     Running   0          4h47m

kube-proxy-j8bf5                            1/1     Running   0          4h47m

kube-scheduler-jwdkube-master-01            1/1     Running   1          140m

tiller-deploy-6f6fd74b68-5xt54              1/1     Running   0          112m

It seems to be a problem of Flannel v0.9.1 compatibility with Kubernetes cluster v1.12.2. Once you replace URL in master configuration playbook it should help:

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/
kube-flannel.yml

To enforce this solution on the current cluster:

1. 
   

   On the master node delete relevant objects for Flannel v0.9.1:

   
   
   

   kubectl delete clusterrole flannel -n kube-system

   
   
   

   kubectl delete clusterrolebinding flannel-n kube-system

   
   
   

   kubectl delete clusterrolebinding flannel -n kube-system

   
   
   

   kubectl delete serviceaccount flannel -n kube-system

   
   
   

   kubectl delete configmap kube-flannel-cfg -n kube-system

   
   
   

   kubectl delete daemonset.extensions kube-flannel-ds -n kube-system

   
   
   

   Proceed also with Flannel Pods deletion:

   
   
   

   kubectl delete pod kube-flannel-ds-5bzrx -n kube-system

   
   
   

   kubectl delete pod kube-flannel-ds-bfs9k -n kube-system

   
   
   

   And check whether no more objects related to Flannel exist:

   
   
   

   kubectl get all --all-namespaces

   
   

2. Install the latest Flannel version to your cluster:

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

For me it works, however if you discover any further problems write a comment below this answer.