getting this error !! The connection to the server localhost:8080 was refused - did you specify the right host or port?

Question

when i run this command mentioned below kubectl get po -n kube-system I get this error :: The connection to the server localhost:8080 was refused - did you specify the right host or port?

Answer 1

I have one K8S server works well and didn't make any management or update changes to it.

One day it suddenly goes down after one reboot. The error looks like this when you issue any kubectl command:

The connection to the server xx.xx.xx.xx:6443 was refused - did you
specify the right host or port?

One very possible reason is the certificate expiration.

Check K8S certs:

admin@hostname:~$ sudo -i
[sudo] password for admin:
root@hostname:~#  kubeadm certs check-expiration
[check-expiration] Reading configuration from the cluster...
[check-expiration] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[check-expiration] Error reading configuration from the Cluster. Falling back to default configuration

CERTIFICATE                EXPIRES                  RESIDUAL TIME   CERTIFICATE AUTHORITY   EXTERNALLY MANAGED
admin.conf                 Jun 09, 2022 07:52 UTC   135d                                    no
apiserver                  Jun 09, 2022 07:52 UTC   135d            ca                      no
apiserver-etcd-client      Jun 09, 2022 07:52 UTC   135d            etcd-ca                 no
apiserver-kubelet-client   Jun 09, 2022 07:52 UTC   135d            ca                      no
controller-manager.conf    Jun 09, 2022 07:52 UTC   135d                                    no
etcd-healthcheck-client    Dec 31, 2021 04:11 UTC   **<invalid>**       etcd-ca                 no
etcd-peer                  Dec 31, 2021 04:11 UTC   **<invalid>**       etcd-ca                 no
etcd-server                Dec 31, 2021 04:11 UTC   **<invalid>**       etcd-ca                 no
front-proxy-client         Jun 09, 2022 07:52 UTC   135d            front-proxy-ca          no
scheduler.conf             Jun 09, 2022 07:52 UTC   135d                                    no

CERTIFICATE AUTHORITY   EXPIRES                  RESIDUAL TIME   EXTERNALLY MANAGED
ca                      Nov 03, 2030 13:32 UTC   8y              no
etcd-ca                 Nov 03, 2030 13:32 UTC   8y              no
front-proxy-ca          Nov 03, 2030 13:32 UTC   8y              no

And we can see some certs are invalid. Renew them:

root@hostname:~# kubeadm certs renew etcd-healthcheck-client
[renew] Reading configuration from the cluster...
[renew] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[renew] Error reading configuration from the Cluster. Falling back to default configuration
certificate for liveness probes to healthcheck etcd renewed

root@hostname:~# kubeadm certs renew etcd-peer
[renew] Reading configuration from the cluster...
[renew] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[renew] Error reading configuration from the Cluster. Falling back to default configuration
certificate for etcd nodes to communicate with each other renewed

root@hostname:~# kubeadm certs renew etcd-server
[renew] Reading configuration from the cluster...
[renew] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[renew] Error reading configuration from the Cluster. Falling back to default configuration 
certificate for serving etcd renewed

Answer 2

Hey I resolved my error of:

Try using this GitHub thread and read the entire comment and do exactly as it says:

https://github.com/Hawaiideveloper/Infastructure-as-Code-Sample_Env/issues/15#issuecomment-811377749

It turned out to be a combination of commands and references to incompatible docker versions, as well as some minor things that Kubernetes documentation 03-31-2021 forgot to mention.

Answer 3

localhost:8080 is the default server to connect to if there is no kubeconfig present on your system (for the current user).

Follow the instructions on the page linked. You will need to execute something like:

gcloud container clusters get-credentials [CLUSTER_NAME]