How to write your own Ganglia gmetric monitors

 

To define a new metric to monitor below is a an example

This metric could read and monitor the number of users currently logged in to the system and display the graph in ganglia front end.

Path for gmetric command:

Soaris: /usr/local/bin/gmetric

Aix: /opt/freeware/bin/gmetric

Linux: /usr/bin/gmetric

This command is available for all users.

Below is the command to monitoring number of users and display corresponding graph in Ganglia front end

/usr/local/bin/gmetric --name Current_Users --value `who |wc -l` --type int32 –unit current_users

Here:

/usr/local/bin/gmetric -> is the ganglia client command

--name Current_Users  -> this will be the name of graph

--value `who |wc -l` -> this is the value(this command should return a single number)

--type int32 -> type of value(since it’s a number its int32)

 

Now you can either crontab this command or  just loop it as below.

#while true; do /usr/local/bin/gmetric --name Current_Users --value `who |wc -l` --type int32 --unit current_users; sleep 10; done

Now this graph is visible on ganglia portal.