We have a couple servers (1 Active / 1 Standby) that we want to load balance to from a F5 Vip. The problem is that the only way to determine which is active and which is standby, is to check the contents of a text file (active || standby). We want the healthcheck to succeed on a server that has the file contents 'active' and fail for the contents 'standby' so that the only active pool member will be the active server. We are unable to customize these systems as they are vendor provided 'appliances' so this is truly the only way to determine which node is the active.
From looking around, the way to do this would be to use an external monitor that runs a shell script. I can't find any other instances of people trying this.
The shell script would be easy to build but I'm not sure how to implement it. Can anyone provide guidance?