add encryptionAlgorithm for ClusterConfigration (#11751)

Signed-off-by: bo.jiang <bo.jiang@daocloud.io>

roles/kubernetes/control-plane/defaults/main/main.yml

@@ -236,3 +236,8 @@ kube_apiserver_tracing_sampling_rate_per_million: 100
 
 # Enable kubeadm file discovery if anonymous access has been removed
 kubeadm_use_file_discovery: "{{ remove_anonymous_access }}"
+
+# Supported asymmetric encryption algorithm types for the cluster's keys and certificates.
+# can be one of RSA-2048(default), RSA-3072, RSA-4096, ECDSA-P256
+# ref: https://kubernetes.io/docs/reference/config-api/kubeadm-config.v1beta4/#kubeadm-k8s-io-v1beta4-ClusterConfiguration
+kube_asymmetric_encryption_algorithm: "RSA-2048"

roles/kubernetes/control-plane/templates/kubeadm-config.v1beta4.yaml.j2

@@ -37,6 +37,7 @@ patches:
 apiVersion: kubeadm.k8s.io/v1beta4
 kind: ClusterConfiguration
 clusterName: {{ cluster_name }}
+encryptionAlgorithm: {{ kube_asymmetric_encryption_algorithm }}
 etcd:
 {% if etcd_deployment_type != "kubeadm" %}
   external: