Assert correct limit usage

This should prevent confusing errors with undefined variables

roles/kubernetes/preinstall/tasks/0040-verify-settings.yml

@@ -1,4 +1,19 @@
 ---
+- name: Stop if any host not in '--limit' does not have a fact cache
+ vars:
+ uncached_hosts: "{{ (hostvars | selectattr('ansible_default_ipv4', 'undefined')).keys() }}"
+ excluded_hosts: "{{ hostvars.keys() | difference(lookup('inventory_hostnames', ansible_limit)) }}"
+ assert:
+ that: uncached_hosts | intersect(excluded_hosts) == 0
+ fail_msg: |
+ Kubespray does not support '--limit' without a populated facts cache for the excluded hosts.
+ Please run the facts.yml playbook first without '--limit'.
+ The following excluded hosts are not cached: {{ uncached_hosts | intersect(excluded_hosts) }}
+ run_once: true
+ when:
+ - ansible_limit is defined
+ - not ignore_assert_errors
+
 - name: Stop if kube_control_plane group is empty
  assert:
  that: groups.get( 'kube_control_plane' )