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Forum Discussion

Joe_Curl_105786's avatar
Joe_Curl_105786
Icon for Nimbostratus rankNimbostratus
Feb 07, 2014

HTTP Redirect When Pool is down

I would like to craft an iRule that detects the pool assigned to the VIP has all members down. When it is down then do an http redirect to our site down web server. I have rules in place where I ca...
application delivery
design
devops
iRules
IheartF5_45022's avatar
IheartF5_45022
Icon for Nacreous rankNacreous
Feb 10, 2014

The advantages of using LB_FAILED are that;

 

  • it catches when the pool is down (no active members) and also when the pool has not been marked down, but the pool member chosen is unresponsive, so it's actually more powerful than just checking [active_members [LB::server pool]]
  • it's slightly more efficient as it saves potentially unnecessary checking in HTTP_REQUEST and you wouldn't need to worry about event disabling in HTTP_REQUEST (assuming you do not implement LB_FAILED in your other iRules) - this may not be a concern but worth noting

There may be other situation-specific reasons for wanting to execute the check in HTTP_REQUEST but if not LB_FAILED works well too as a generic rule for catching errors.