External monitoring

Hi Matt,

 

 

First off, there are several different ways to tackle this problem, each with its own architectural strengths and weaknesses. I'll touch on the ones I know of, and if I miss anything, someone will tag on, I'm sure.

 

 

1. Use WMI or SNMP with a custom Monitor. This would allow you to get information from the DB about its status and use a global variable in an iRule to deny access if the CPU usage is too high. This method creates a lag while the BIG-IP waits for the system to return information.

 

2. Use iControl to monitor the CPU on the DB server and set an iRule to deny access (again with a global to say whether access should be denied or not). From iControl, iRules can be enabled and disabled relatively easily. This method is basically recreating a monitor - but on the DB server.

 

3. Do it all with iRules and WMI or SNMP. This again would recreate the reason monitors exist, and due to the interpreted nature of iRules combined with the remote call would be the slowest of the three options.

 

 

To get started with iControl, make sure that your development environment of choice is installed, and download the API from the download section - there are samples and step-by-step documents there and on the iControl wiki. Joe and I have also written some documents and filmed some videos to help get started with different languages - these are accessible through the "Documents|Tutorials" menu, above.

 

 

I hope this at least gets you pointed in directions to start looking.

 

 

Don.