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Xavier_113679's avatar
Xavier_113679
Icon for Nimbostratus rankNimbostratus
Aug 06, 2012

Passing variable to http monitor

Hi, I'm trying to setup a monitor for a pool containing 3 members that will call a servlet located on a different server. Here's an idea

 

 

GET /rsa_check?$NODE HTTP/1.1\nHost: server_hosting_servlet:9502\nConnection: Close\n\r\n

 

 

 

My problem is the $NODE. I basically need to pass the member hostname to a url which will in turn be processed on a server external to the pool configured in F5.

 

 

 

I tried to look for a list of variables that could eventually be passed to the GET string as part of the http health monitor, but I've been unsuccessful so far.

 

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  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Aug 08, 2012
    Hi Xavier,

     

     

    This isn't currently possible. Internally, the monitor is associated with an IP:port combination as opposed to a pool member. You'd need to create a custom monitor per pool member with the custom string hardcoded and then apply that monitor to the specific pool member.

     

     

    Aaron
  • Xavier_113679's avatar
    Xavier_113679
    Icon for Nimbostratus rankNimbostratus
    Aug 08, 2012
    Aaron, when you refer to custom monitor, you refer to external monitor, right? External monitor would do the trick indeed as I could use the $1 variable representing the pool member IP (IPV6 format though). There would not even be a need to create individual monitors per pool member. But from what I've heard from F5 support, external monitor are not recommended in terms of best practices, hence why I'm trying to find a solution with the http monitor.
  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Aug 08, 2012
    You could put in a feature request to get the monitored IP:port if that's not possible currently. External monitors use more CPU/memory compared with an inbuilt monitor.

     

     

    Aaron