drbd-utils: check if Nagios/Munin are installed

drbd-utils/tasks/munin.yml

@@ -1,15 +1,22 @@
 ---
 
+- name: Check if Munin plugins exists
+  stat:
+    path: /etc/munin/plugins/
+  register: munin_plugins_dir
+
 # https://raw.githubusercontent.com/munin-monitoring/contrib/master/plugins/drbd/drbd
 - name: Get Munin plugin
   copy:
     src: munin/drbd-plugin
     dest: /etc/munin/plugins/drbd
     mode: "755"
+  when: munin_plugins_dir.stat.exist
   notify: restart munin-node
 
 - name: Copy Munin plugin conf
   copy:
     src: munin/drbd-config
     dest: /etc/munin/plugin-conf.d/drbd
+  when: munin_plugins_dir.stat.exist
   notify: restart munin-node

drbd-utils/tasks/nagios.yml

@@ -1,8 +1,14 @@
 ---
 
+- name: Check if Nagios is installed
+  stat:
+    path: /usr/local/lib/nagios/plugins/
+  register: nagios_plugins_dir
+
 - name: Mount /usr in rw
   command: mount -o remount,rw /usr warn=no
   changed_when: False
+  when: nagios_plugins_dir.stat.exist
 
 # https://exchange.nagios.org/components/com_mtree/attachment.php?link_id=3367&cf_id=30
 - name: Install Nagios plugin
@@ -10,3 +16,4 @@
     src: "nagios/check_drbd"
     dest: "/usr/local/lib/nagios/plugins/check_drbd"
     mode: "755"
+  when: nagios_plugins_dir.stat.exist