measure memory as percentage

check_pve.rb

@@ -355,6 +355,21 @@ class CheckPve
     check_thresholds(data: value)
   end
 
+  # helper for nested percentage values
+  def node_helper_to_nested_pct(path: 'status', key:, value:, output_msg:, perf_label: 'Usage', **args)
+    http_connect(path: "api2/json/nodes/#{@options[:node]}/#{path}")
+    data = JSON.parse(@response.body)['data'][key]
+    # calc used data
+    value = if args.empty?
+              format_float(float_data: data[value])
+            else
+              format_float(float_data: data[value].to_f / data[args[:value_to_compare]])
+            end
+    build_output(msg: "#{output_msg}: #{value}%")
+    build_perfdata(perfdata: "#{perf_label}=#{value}%")
+    check_thresholds(data: value)
+  end
+
   # helper for unit values
   def node_helper_to_units(path: 'status', type:, value: 'used', output_msg:, unit: 'gb', perf_label: 'Usage')
     http_connect(path: "api2/json/nodes/#{@options[:node]}/#{path}")
@@ -395,7 +410,12 @@ class CheckPve
   ### node: memory
   def mem
     return unless @options[:mode] == 'memory'
-    node_helper_to_units(type: 'memory', output_msg: 'Memory Usage')
+    node_helper_to_nested_pct(
+      key: 'memory',
+      value: 'used',
+      value_to_compare: 'total',
+      output_msg: 'Memory usage'
+    )
   end
 
   ### node: ksm