Counting available instances

Discussion created by mick.sheppard on May 1, 2012
Latest reply on May 2, 2012 by mick.sheppard

Has anyone any tips on how to count the number of instances of a particular application are currently available?

I'll add a bit of detail:

We are running a number of JVMs for each application suite in an N+1 configuration.

We would like out APM dashboard to reflect the status of these JVMs. Say going amber if we are down to N available, and red if fewer than N are available.

I had a CA Consultant use the Agent Connection Status metric in the Custom Metric Agent. This gives a value of 1 for a valid connection but a 3 for a period of time if the connection is lost which makes it unsuitable. I've used a Javascript script running on the collectors in the past to push a count in the Custom Metric Agent. This worked but, in order to cope with alerting if their are no instances running, I had to modify the script whenever a new JVM was added to get 0 values for collectors that had none connected.

If anyone has a better way of doing this I'd really like to know.