InformationExplicitly set a service account private key file for service accounts on the controller manager.
To ensure that keys for service account tokens can be rotated as needed, a separate public/private key pair should be used for signing service account tokens. The private key should be specified to the controller manager with `--service-account-private-key-file` as appropriate.
SolutionEdit the `/etc/kubernetes/controller-manager` file on the master node and set the `KUBE_CONTROLLER_MANAGER_ARGS` parameter to `--service-account-private-key-file=`: `KUBE_CONTROLLER_MANAGER_ARGS='--service-account-private-key-file='`
Based on your system, restart the `kube-controller-manager` service. For example: `systemctl restart kube-controller-manager.service`
You would need to securely maintain the key file and rotate the keys based on your organization's key rotation policy.