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I am getting connection refused error while fetching the nodes of my kubernetes cluster from master. I have tried all debugging methods available in the internet but none seems working. I have one master node and 2 worker node setup in my cluster.

  1. kubectl get nodes

    master@master-vm:~$ kubectl get nodes
The connection to the server X.X.X.X:6443 was refused - did you specify the right host or port?
master@master-vm:~$

  2. Kubelet status

    master@master-vm:~/.kube$ systemctl status kubelet
Active: active (running) since Tue 2021-03-16 19:53:33 IST; 20s ago
kubelet.go:2263] node "master-vm" not found

  3. Docker Status

    master@master-vm:~$ systemctl status docker
 ● docker.service - Docker Application Container Engine
Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
Active: active (running) since Tue 2021-03-16 19:37:59 IST;

  4. 6443 Port details in netstat

    master@master-vm:~$ sudo netstat -pnlt | grep 6443
[sudo] password for master:
tcp6      76      0 :::6443                 :::*                    LISTEN      1107/kube-apiserver
master@master-vm:~$

  5. Swap is OFF

    master@master-vm:~$ sudo swapoff -a
master@master-vm:~$ free -m
              total        used        free      shared  buff/cache   available
Mem:           3936        1159        1468          11        1307        2545
Swap:             0           0           0
master@master-vm:~$

  6. Kubectl version

    master@master-vm:~$ kubectl version
Client Version: version.Info{Major:"1", Minor:"17", 
GitVersion:"v1.17.4",
GitCommit:"8d8aa39598534325ad77120c120a22b3a990b5ea", 
GitTreeState:"clean", 
BuildDate:"2020-03-12T21:03:42Z", 
GoVersion:"go1.13.8", 
Compiler:"gc", 
Platform:"linux/amd64"}

The connection to the server X.X.X.X:6443 was refused - did you specify the right host or port?
master@master-vm:~$

  7. Firewall Status

    master@master-vm:~$ sudo ufw status verbose #ubuntu
Status: inactive
master@master-vm:~$ sudo ufw disable #ubuntu
Firewall stopped and disabled on system startup
master@master-vm:~$

  8. /etc/hosts

    127.0.0.1       localhost
127.0.1.1       master-vm

  9. Kubeadm Version

     master@master-vm:~$ kubeadm version
 kubeadm version: &version.Info{Major:"1", Minor:"17", 
 GitVersion:"v1.17.4", 
 GitCommit:"8d8aa39598534325ad77120c120a22b3a990b5ea", 
 GitTreeState:"clean", 
 BuildDate:"2020-03-12T21:01:11Z", 
 GoVersion:"go1.13.8", 
 Compiler:"gc", 
 Platform:"linux/amd64"}
 master@master-vm:~$

  10. Kubectl config view

     master@master-vm:~/.kube$ kubectl config view
 apiVersion: v1
 clusters:
   cluster:
     certificate-authority-data: DATA+OMITTED
     server: https://X.X.X.X:6443
   name: kubernetes
 contexts:
   context:
     cluster: kubernetes
     user: kubernetes-admin
   name: kubernetes-admin@kubernetes
 current-context: kubernetes-admin@kubernetes
 kind: Config
 preferences: {}
 users:
   name: kubernetes-admin
   user:
     client-certificate-data: REDACTED
     client-key-data: REDACTED
 master@master-vm:~/

Any suggestion on how to rectify the above error ?

Som
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2 Answers2

1

It looks to me that api server runs on ipv6 (notice the tcp6 in the output of netstat).

Try starting your k8s with

kubeadm init --apiserver-advertise-address=<private-ipv4 of master host>

--apiserver-advertise-address - The IP address the API Server will advertise it's listening on. If not set the default network interface will be used.

If this does not help, you may want to have a look at api-server logs. Either use docker logs to get the logs or:

cat /var/log/pods/kube-system_kube-apiserver-master-vm_xxxxxxx/kube-apiserver/0.log
Matt
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0

Try executing the following lines of code on the master node.

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

Next try executing kubectl get nodes on the same master node and it should work fine.

skogul1997
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