Use external LB IP for external api endpoint (kubernetes-sigs#4060)

* Use external LB IP for external api endpoint

Use loadbalancer_apiserver.address instead of apiserver_loadbalancer_domain_name for kudadm init --apiserver-advertise-address argument

https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-init/#options states apiserver-advertise-address needs to be a IPv4 or IPv6 address

* only use loadbalancer IP if it is defined

roles/kubernetes/client/tasks/main.yml

@@ -2,13 +2,13 @@
 - name: Set external kube-apiserver endpoint
   set_fact:
     external_apiserver_address: >-
-      {%- if loadbalancer_apiserver is defined and loadbalancer_apiserver.port is defined -%}
-      {{ apiserver_loadbalancer_domain_name }}
+      {%- if loadbalancer_apiserver is defined and loadbalancer_apiserver.address is defined -%}
+      {{ loadbalancer_apiserver.address }}
       {%- else -%}
       {{ kube_apiserver_access_address }}
       {%- endif -%}
     external_apiserver_port: >-
-      {%- if loadbalancer_apiserver is defined and loadbalancer_apiserver.port is defined -%}
+      {%- if loadbalancer_apiserver is defined and loadbalancer_apiserver.address and loadbalancer_apiserver.port is defined -%}
       {{ loadbalancer_apiserver.port|default(kube_apiserver_port) }}
       {%- else -%}
       {{ kube_apiserver_port }}