Parameters to iRules?

Hi Craig,

 

 

As you suggest, you can either configure a global parameter in RULE_INIT (or in any event of any iRule) or you can use a datagroup (called a class in the bigip.conf). I don't think there is a significant difference between referencing a global parameter compared with referencing a class. You could test this using timing or by looping a few hundred or thousand references and comparing the times.

 

 

A reference to either object is checked on every attempt--there isn't any caching. Generally, I've suggested our clients use a global variable if it's something the administrator won't need to modify on a regular basis. If it's something an end user would need to view or change regularly a datagroup is probably easier. Modifying a global variable within the iRule requires reloading the entire rule, whereas modifying a datagroup doesn't.

 

 

Aaron