Kubernetes: Certificate has expired while Joining node to Cluster

Not able to Join Kubernetes node to Cluster?

Kubernetes

Kubernetes coordinates a highly available cluster of computers that are connected to work as a single unit. The Kubernetes allow you to deploy containerized applications to a cluster without tying them specifically to individual machines.

A Kubernetes cluster consists of two types of resources:

The Master that coordinates the cluster

Nodes are the workers who runs the applications.

You can Use kubeadm join  to add any node into kubernets cluster.  While joining the node i faced this Error.

Error:
[Discovery] Failed to request cluster info, will try again: [Get https://IP:Port/api/v1/namespaces/kube-public/configmaps/cluster-info: x509: certificate has expired or is not yet valid]



Solution:

1. Check if time is sync between Master and Node. If Not then do the following on both Master and node. Then  try to join again.

a. Install NTP.

yum install ntp -y

 b. Start ntp.
                                                       
service ntpd start && systemctl enable ntpd


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