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 Controller Manager pod specification file '/etc/kubernetes/manifests/kube-controller-manager.yaml' on the master node and set the '--service-account-private-key-file' parameter to the private key file for service accounts.
You would need to securely maintain the key file and rotate the keys based on your organization's key rotation policy.