Add a Custom Monitoring Plugin Automatically with RightScripts or Chef Recipes

Create a Custom Plugin

Unfortunately, there is a variety of monitoring information which cannot be queried from the Windows Management Instrumentation (WMI), especially for older platforms like Windows Server 2003.  In such cases, a script is required to handle the gathering and sending of monitoring information via collectd.  There are two different ways that you can create a custom monitoring plugin.

• DSL Option
• Pure Ruby Option

wmi_query                 'Select FreePhysicalMemory from Win32_OperatingSystem'
wmi_query_send_attributes 'FreePhysicalMemory'
collectd_plugin           'memory'
collectd_type             'memory'
collectd_type_instance    'free'
collectd_units_factor     1024

def run
  drives = execute_wmi_query("Select deviceid, freespace, size from win32_logicaldisk")
  for drive in drives do
    if drive.deviceid =~ /^(\w):$/
      drive_letter = $1
      free_space_val = drive.freespace
      drive_size_val = drive.size
      if is_number?(free_space_val) && is_number?(drive_size_val)
        used_space = drive_size_val.to_i - free_space_val.to_i
        @logger.debug("Drive #{drive_letter}: has #{free_space_val} free and #{used_space} used space")
        gauge('df', '', 'df', "drive_#{drive_letter}", [ used_space, free_space_val.to_i ])
      end
    end
  end
endThe content of the plugin file will be instance eval'd into a new instance of a Monitor class. The Monitor class provides the bridge between the monitoring script and the user-defined plugin. This type of plugin is simple for RightScale to implement and fairly straight forward for users to add their own monitoring plugins.

Create a Script to Deploy the Custom Monitoring Plugin

Once you've created a custom monitoring plugin, you can either use a RightScript or Chef Recipe for deployment so that the plugin is installed in the proper directory on the instance at launch time.

Even though RightLink itself is installed to the x64 Program Files location on 64-bit platforms, the custom monitoring plugin must always be deployed to the x86 install location for both 32-bit and 64-bit platforms.  For your convenience, RightLink will provide an environment variable called "RS_MONITORS_DIR" which will indicate the proper location on the instance's disk for plugins to be deployed.  You should always use this variable instead of trying to hardcode an absolute path.

Inside the directory, you'll find the plugins that RightScale automatically installs by default:

• cpu_load.rb
• disk_usage.rb
• memory.rb
   

RightScript Example

The following PowerShell code can be used when creating a RightScript with 'my-monitor.rb' as attachment:

$ErrorActionPreference = "Stop"
$pluginFileName = "my-monitor.rb" $srcPluginFilePath = Join-Path $env:RS_ATTACH_DIR $pluginFileName $dstPluginFilePath = Join-Path $env:RS_MONITORS_DIR $pluginFileName
write-output "Copying from $srcPluginFilePath to $dstPluginFilePath" Copy-Item $srcPluginFilePath $dstPluginFilePath -Force write-output "Monitor copied"

Chef Recipe Example

The following Ruby code can be used when creating a Chef Recipe:

require 'fileutils'
ruby 'copy custom monitors' do plugin_file_name = "my-monitor.rb" src_plugin_file_path = File.join(ENV['RS_ATTACH_DIR'], plugin_file_name)
dst_plugin_file_path = File.join(ENV['RS_MONITORS_DIR'], plugin_file_name) FileUtils.cp(src_plugin_file_path, dst_plugin_file_path) end

Add the Script to a ServerTemplate

The last step is to add the RightScript or Chef Recipe to a Windows ServerTemplate.   When you add the script to your ServerTemplate, be sure to add it as a Boot Script after the "sys monitoring" script that installs the default monitoring plugins.

Test and Verify

Launch a Server using the modified ServerTemplate to test and verify that the custom monitoring plugin was successfully installed and that you can view your custom graphs in the Dashboard. 

Congratulations!  You just created a custom monitoring plugin, created a script to properly deploy the plugin, and added it to one of your Windows ServerTemplates.