chore: capture k3s secondary install diagnostics on failure

ansible/roles/k3s-server/tasks/main.yml

@@ -67,13 +67,45 @@
     - k3s_primary | default(false)
 
 - name: Install k3s server (secondary)
-  environment:
-    INSTALL_K3S_VERSION: "{{ k3s_version if k3s_version != 'latest' else '' }}"
-    K3S_TOKEN: "{{ k3s_token }}"
-  command: /tmp/install-k3s.sh server --server https://{{ k3s_primary_ip }}:6443 --advertise-address={{ k3s_node_ip }} --node-ip={{ k3s_node_ip }}
-  when: 
+  when:
     - k3s_install_needed
     - not (k3s_primary | default(false))
+  block:
+    - name: Run secondary k3s install
+      environment:
+        INSTALL_K3S_VERSION: "{{ k3s_version if k3s_version != 'latest' else '' }}"
+        K3S_TOKEN: "{{ k3s_token }}"
+      command: /tmp/install-k3s.sh server --server https://{{ k3s_primary_ip }}:6443 --advertise-address={{ k3s_node_ip }} --node-ip={{ k3s_node_ip }}
+      register: secondary_install
+
+  rescue:
+    - name: Show k3s service status after failed secondary install
+      command: systemctl status k3s --no-pager
+      register: k3s_status_after_install
+      changed_when: false
+      failed_when: false
+
+    - name: Show recent k3s logs after failed secondary install
+      command: journalctl -u k3s -n 120 --no-pager
+      register: k3s_journal_after_install
+      changed_when: false
+      failed_when: false
+
+    - name: Fail with secondary install diagnostics
+      fail:
+        msg: |
+          Secondary k3s install failed on {{ inventory_hostname }}.
+          Install stdout:
+          {{ secondary_install.stdout | default('n/a') }}
+
+          Install stderr:
+          {{ secondary_install.stderr | default('n/a') }}
+
+          Service status:
+          {{ k3s_status_after_install.stdout | default('n/a') }}
+
+          Recent logs:
+          {{ k3s_journal_after_install.stdout | default('n/a') }}
 
 - name: Wait for k3s to be ready
   command: "{{ (k3s_primary | default(false)) | ternary('kubectl get nodes', 'systemctl is-active k3s') }}"