fix: reinstall stale unregistered k3s nodes

ansible/site.yml

@@ -118,6 +118,18 @@
     # Use Load Balancer for HA - all control planes join via LB endpoint
     k3s_join_endpoint: "{{ kube_api_endpoint | default(hostvars[groups['control_plane'][0]]['k3s_primary_private_ip']) }}"
 
+  pre_tasks:
+    - name: Check whether secondary control plane is registered in Kubernetes
+      command: kubectl get node/{{ inventory_hostname }}
+      delegate_to: "{{ groups['control_plane'][0] }}"
+      register: k3s_node_registration
+      changed_when: false
+      failed_when: false
+
+    - name: Record secondary control plane registration state
+      set_fact:
+        k3s_node_registered: "{{ k3s_node_registration.rc == 0 }}"
+
   roles:
     - k3s-server
 
@@ -234,6 +246,18 @@
     k3s_server_url: "https://{{ kube_api_endpoint | default(hostvars[groups['control_plane'][0]]['k3s_primary_private_ip']) }}:6443"
     k3s_node_ip: "{{ k3s_private_ip }}"
 
+  pre_tasks:
+    - name: Check whether worker is registered in Kubernetes
+      command: kubectl get node/{{ inventory_hostname }}
+      delegate_to: "{{ groups['control_plane'][0] }}"
+      register: k3s_node_registration
+      changed_when: false
+      failed_when: false
+
+    - name: Record worker registration state
+      set_fact:
+        k3s_node_registered: "{{ k3s_node_registration.rc == 0 }}"
+
   roles:
     - k3s-agent