Information
Explicitly set a service account private key file for service accounts on the controller manager.
Rationale:
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.
Solution
Edit 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.
--service-account-private-key-file=<filename>
Impact:
You would need to securely maintain the key file and rotate the keys based on your organization's key rotation policy.
Default Value:
By default, --service-account-private-key-file it not set.
References:
https://kubernetes.io/docs/admin/kube-controller-manager/