Add preflight checks

tasks/main.yml

@@ -1,4 +1,6 @@
 ---
+- include: preflight.yml
+
 - name: Create the Node Exporter group
   group:
     name: "node-exp"

tasks/preflight.yml

@@ -0,0 +1,6 @@
+---
+- name: check collectors
+  fail:
+    msg: "Collector cannot be both disabled and enabled"
+  when: '"{{ item }}" in "{{ node_exporter_enabled_collectors }}"'
+  with_items: "{{ node_exporter_disabled_collectors }}"