Forum Discussion

khammer_260526's avatar
khammer_260526
Icon for Nimbostratus rankNimbostratus
Nov 06, 2018

Understanding Pool Monitors vs Node Monitors

We have set up a custom HTTP ECV monitor set for our pool that does a Send to a particular URL in our application and then checks for a particular string to match. Currently, there is just one node in the pool. The node uses the F5 supplied tcp_half_open to monitor the health of the node. I have 2 questions about this set up. 1) The ECV monitor does a GET to a particular URL in the application, but we do not see this request in our access log for the application. This leads us to believe that it does not work. Why don't we see the monitor GET in these logs? 2) When I try enabling logging of the pool monitoring on the F5, it doesn't log the pool health check (our custom ECV monitor), but only logs the node monitor, tcp_half_open. According to article K12531, I should be able to log the activities of pool monitor, but that does not seem to be the case. How can I log the activity of the pool monitor?

 

1 Reply

  • Surgeon's avatar
    Surgeon
    Ret. Employee

    The 1st thing you should know is that pool member object identifies by address and port, whereas node just by ip address.

     

    Thus, you can not use tcp_half_open monitor on node object since this type of monitor requires TCP port number. This means that this monitor is applies to the pool or pool member.

     

    The 2d thing, you need to confirm that ecv monitor is applied to pool or pool member at all? Can you provide config of your pool and your ecv monitor?