Undefined check for apiserver_loadbalancer_domain_name in apiserver_sans (#13009)

Author: chadswen

roles/kubernetes/control-plane/tasks/kubeadm-setup.yml

@@ -36,7 +36,7 @@
       - "localhost"
       - "127.0.0.1"
       - "::1"
-      - "{{ apiserver_loadbalancer_domain_name }}"
+      - "{{ apiserver_loadbalancer_domain_name | d('') }}"
       - "{{ loadbalancer_apiserver.address | d('') }}"
       - "{{ supplementary_addresses_in_ssl_keys }}"
       - "{{ groups['kube_control_plane'] | map('extract', hostvars, 'main_access_ip') }}"