nagios: Added support for checking Linux md arrays to nrpe

custom/lib/facter/mdarrays.rb

@@ -0,0 +1,15 @@
+Facter.add(:mdarrays) do
+    confine :kernel => :linux
+    setcode do
+        arrays = []
+        mdstat = "/proc/mdstat"
+        if File.exists?(mdstat)
+            File.readlines(mdstat).each do |line|
+                if m = line.match(/^md[0-9]+/)
+                    arrays << m[0]
+                end
+            end
+        end
+        arrays.sort.join(',')
+    end
+end