iRule: react to down pool

The question came up whether it is possible to detect a pool being down and react to that accordingly.

If the pool is down, I'd like to be able to redirect to a system down page and send the original URI so I can log it in our application and periodically retry their original request with a JavaScript timer.

The way to do this is to write a handler for the LB_FAILED event. You can then query the pool and take action according to which pool was selected.

when LB_FAILED { 
  switch [LB::server pool] { 
    pool-customer1 { HTTP::redirect http:://foo/customer1 } 
    pool-customer2 { HTTP::redirect http:://bar/notavail } 
    default { HTTP::redirect http:://sitedown/ } 
  } 
}

Click here for the forum thread.

-Joe