fix: avoid crash when host has no default_ipv6 fact

Jinja's default() filter evaluates its fallback argument eagerly, even
when the primary value already resolved. On hosts with no IPv6 default
route, ansible_facts has no default_ipv6 key at all, so chaining
['address']/.address/.interface onto the missing key raises:

  'dict object' has no attribute 'default_ipv6'

...even though default_ipv4 would have been used. This hit role
argument validation (rke2_api_ip default in argument_specs.yml) on any
IPv4-only host, before the role even started.

Replace the dict['key']/.key chains with .get(key, {}).get(subkey),
which returns None instead of raising when the key is absent, and use
`or` instead of default() so None/empty still falls through to the
IPv6 branch.

Author: Melnyk Roman

defaults/main.yml

@@ -22,7 +22,7 @@ rke2_ha_mode_kubevip: false
 # Kubernetes API and RKE2 registration IP address. The default Address is the IPv4 of the Server/Master node.
 # In HA mode choose a static IP which will be set as VIP in keepalived.
 # Or if the keepalived is disabled, use IP address of your LB.
-rke2_api_ip: "{{ hostvars[groups[rke2_servers_group_name].0]['ansible_default_ipv4']['address'] | default(hostvars[groups[rke2_servers_group_name].0]['ansible_default_ipv6']['address'] ) }}"
+rke2_api_ip: "{{ hostvars[groups[rke2_servers_group_name].0].get('ansible_default_ipv4', {}).get('address') or hostvars[groups[rke2_servers_group_name].0].get('ansible_default_ipv6', {}).get('address') }}"
 
 # optional option for RKE2 Server to listen on a private IP address & port
 # rke2_api_private_ip:

meta/argument_specs.yml

@@ -39,7 +39,7 @@ argument_specs:
 
       rke2_api_ip:
         type: str
-        default: "{{ hostvars[groups[rke2_servers_group_name].0].ansible_facts['default_ipv4']['address'] | default(hostvars[groups[rke2_servers_group_name].0].ansible_facts['default_ipv6']['address'] ) }}"
+        default: "{{ hostvars[groups[rke2_servers_group_name].0].ansible_facts.get('default_ipv4', {}).get('address') or hostvars[groups[rke2_servers_group_name].0].ansible_facts.get('default_ipv6', {}).get('address') }}"
         description: "Kubernetes API and RKE2 registration IP address. The default Address is the IPv4 of the Server/Master node. In HA mode choose a static IP which will be set as VIP in keepalived. Or if the keepalived is disabled, use IP address of your LB."
 
       rke2_api_private_ip:

templates/keepalived.conf.j2

@@ -28,7 +28,7 @@ vrrp_script chk_rke2server {
 }
 
 vrrp_instance VI_1 {
-    interface {{ ansible_facts.default_ipv4.interface | default(ansible_facts.default_ipv6.interface) }}
+    interface {{ ansible_facts.get('default_ipv4', {}).get('interface') or ansible_facts.get('default_ipv6', {}).get('interface') }}
     virtual_router_id 11
 {% if groups[rke2_servers_group_name].0 == inventory_hostname|string() %}
     state MASTER
@@ -41,11 +41,11 @@ vrrp_instance VI_1 {
     {% endif -%}
 {% endfor %}
     advert_int 1
-    unicast_src_ip {{ ansible_facts.default_ipv4.address | default(ansible_facts.default_ipv6.address) }}
+    unicast_src_ip {{ ansible_facts.get('default_ipv4', {}).get('address') or ansible_facts.get('default_ipv6', {}).get('address') }}
     unicast_peer {
 {% for host in groups[rke2_servers_group_name] %}
 {% if host|string() != inventory_hostname|string() %}
-        {{ hostvars[host]['ansible_facts']['default_ipv4']['address'] | default(hostvars[host]['ansible_facts']['default_ipv6']['address'] ) }}
+        {{ hostvars[host]['ansible_facts'].get('default_ipv4', {}).get('address') or hostvars[host]['ansible_facts'].get('default_ipv6', {}).get('address') }}
 {% endif %}
 {% endfor %}
     }

templates/kube-vip/kube-vip.yml.j2

@@ -37,7 +37,7 @@ spec:
             fieldRef:
               fieldPath: spec.nodeName
         - name: vip_interface
-          value: "{{ rke2_interface | default(ansible_facts.default_ipv4.interface | default(ansible_facts.default_ipv6.interface)) }}"
+          value: "{{ rke2_interface | default(ansible_facts.get('default_ipv4', {}).get('interface') or ansible_facts.get('default_ipv6', {}).get('interface')) }}"
         - name: port
           value: "{{ rke2_api_port | default('6443') }}"
         - name: vip_cidr