"unable to fetch kubeadm-config" Displayed When Adding a Node to a Kubernetes Cluster

Symptom

The message "unable to fetch kubeadm-config" is displayed when a node is added to a cluster.

Key Process and Cause Analysis

If an error message is displayed indicating no permission for obtaining the config file, the token is incorrect or invalid. By default, the token on the primary node is retained for only 24 hours. After the validity period expires, the token becomes invalid.

Conclusion and Solution

1. Check the token status on the primary node.

   kubeadm token list

   

2. If the token has expired, create a temporary token.

   kubeadm create token

3. Use the new token to add a new node.