override hosts, add reboot if required

playbooks/aptUpgrade.yml

@@ -1,9 +1,16 @@
 ---
 - name: update apt-cache and upgrade
-  hosts: oracle
-  become: yes
+  # 'all' is okay here, because the fail task will force the user to specify a limit on the command line, using -l or --limit
+  hosts: all 
   tasks:
+    - name: checking limit arg
+      fail:
+        msg: "you must use -l or --limit - when you really want to use all hosts, use -l 'all'"
+      when: ansible_limit is not defined
+      run_once: true
+
     - name: apt
+      become: true
       apt:
           update_cache: yes
           upgrade: 'yes'