"invalid,commas,in,DNS",
					},
				},
			},
		},
		NodeRegistration: kubeadmapi.NodeRegistrationOptions{Name: hostname},
	}

	altNames, err := GetEtcdPeerAltNames(cfg)
	if err != nil {
		t.Fatalf("failed calling GetEtcdPeerAltNames: %v", err)
	}

	expectedDNSNames := []string{hostname, proxy}
	for _, DNSName := range expectedDNSNames {
		t.Run(DNSName, func(t *testing.T) {
			found := false

}

// GetEtcdPeerAltNames builds an AltNames object for generating the etcd peer certificate.
// Hostname and `API.AdvertiseAddress` are included if the user chooses to promote the single node etcd cluster into a multi-node one (stacked etcd).
// The user can override the listen address with `Etcd.ExtraArgs` and add SANs with `Etcd.PeerCertSANs`.

			Config: certutil.Config{
				Usages: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth, x509.ExtKeyUsageClientAuth},
			},
		},
		configMutators: []configMutatorsFunc{
			makeAltNamesMutator(pkiutil.GetEtcdPeerAltNames),
			setCommonNameToNodeName(),
		},
	}
}

// KubeadmCertEtcdHealthcheck is the definition of the cert used by Kubernetes to check the health of the etcd server.