try w/a needs-reboot check first

playbooks/host-reboot.yml

@@ -5,12 +5,19 @@
   user: root
 
   tasks:
+  - name: see if it needs to be rebooted
+    action: shell test -f /usr/local/bin/needs-reboot.py && /usr/local/bin/needs-reboot.py
+    ignore_errors: True
+    register: needsreboot
+
   - name: reboot the host
-    action: command /sbin/reboot
+    action: command touch /tmp/would-reboot
+#/sbin/reboot
+    only_if: '${needsreboot.stdout}.find("yes") != -1'
 
   - name: wait for host to come back - up to 6 minutes
     local_action: wait_for host=${inventory_hostname} port=22 delay=10 timeout=420
-
+    only_if: '${needsreboot.stdout}.find("yes") != -1'