- The CertificateSigningRequest API is promoted to certificates.k8s.io/v1 with the following changes:
  - `spec.signerName` is now required, and requests for `kubernetes.io/legacy-unknown` are not allowed to be created via the `certificates.k8s.io/v1` API
  - `spec.usages` is now required, may not contain duplicate values, and must only contain known usages

- When `--rotate-server-certificates` is enabled, kubelet will no longer request a new certificate on startup if the current certificate on disk is satisfactory. ([#69991](https://github.com/kubernetes/kubernetes/pull/69991), [@agunnerson-ibm](https://github.com/agunnerson-ibm))

- Kubeadm: during execution of the "check expiration" command, treat the etcd CA as external if there is a missing etcd CA key file (etcd/ca.key) and perform the proper validation on certificates signed by the etcd CA. Additionally, make sure that the CA for all...

        }
    }
    
    private boolean isAuthorizedWitnessServer(InetAddress server) {
        // Implementation would check against authorized server list
        // Could use certificates, Kerberos, etc.
        return true;  // Simplified
    }
    
    private boolean isValidNotificationSource(WitnessNotification notification) {
        // Validate notification signature/source

        * requests from a node for a TLS serving certificate for itself are approved if the CSR creator has `create` permission on the `certificatesigningrequests` resource and the `selfnodeserver` subresource in the `certificates.k8s.io` API group

  in kube-apisever and kube-controller-manager pods. Instead, it shifted to supporting the
  mounting of /etc/pki/ca-trust and /etc/pki/tls/certs. The locations /etc/ca-certificate,
  /usr/share/ca-certificates, /usr/local/share/ca-certificates, and /etc/ssl/certs continued
  to be supported. ([#124361](https://github.com/kubernetes/kubernetes/pull/124361), [@neolit123](https://github.com/neolit123))

* AWS kube-up: tolerate a lack of ephemeral volumes ([#23776](https://github.com/kubernetes/kubernetes/pull/23776), [@justinsb](https://github.com/justinsb))
* Fix so setup-files don't recreate/invalidate certificates that already exist ([#23550](https://github.com/kubernetes/kubernetes/pull/23550), [@luxas](https://github.com/luxas))



# v1.2.1

- Kubeadm: during execution of the "check expiration" command, treat the etcd CA as external if there is a missing etcd CA key file (etcd/ca.key) and perform the proper validation on certificates signed by the etcd CA. Additionally, make sure that the CA for all...

- Kubeadm: during execution of the "check expiration" command, treat the etcd CA as external if there is a missing etcd CA key file (etcd/ca.key) and perform the proper validation on certificates signed by the etcd CA. Additionally, make sure that the CA for all...

  - Some kubeadm commands are now allowed to work in a completely offline mode.
- Certificate handling improvements:
  - Renew certs as part of upgrade.
  - New `kubeadm alpha phase certs renew` command for renewing certificates.
  - Certificates created with kubeadm now have improved uniqueness of Distinguished Name fields.
- HA improvements: