F5 APM Variable Assign agent

In simple terms, session variables are the mechanism that APM uses to store data about user's sessions. This data has these properties:

1- It's stored in BIG-IP's high speed session database, which is the same one that is used to store information about sticky load balancing.

2- The data is string values that may include unicode characters. Array values are strings that are delimited by pipe | characters.

3- The names of the variables are loosely hierarchical, but do not follow any strict naming rules. You may set a session variable with any name you like. Here's a reference with some of the common variables used.

4- Session variables are scoped per user. User sessions do not have access to each other's session variables.

5- Session variables (usually tokens or passwords) may be encrypted in-memory so that a process dump will not contain sensitive data. The encryption key is a combination of a dynamic nonce used for that session and the BIG-IP's master key.

 

The Variable Assign agent simply allows you to set one of these session variables to a custom value you choose.

Here's a lab that talks about that VPE agent, how to use it, and why it's there:

https://f5-agility-labs-iam.readthedocs.io/en/latest/class8/module4/module4.html#