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Joe_Erchul_4263's avatar
Joe_Erchul_4263
Icon for Nimbostratus rankNimbostratus
May 31, 2011

Failing node members in a pool based on a different pool.

Gang,

 

 

I've gotten an interesting question from an Application Developer. They currently have two distinct pools behind my V10 load-balancers, with two discreet servers in each pool (total servers = 4). I've got their pools set for Priority Group load-balancing, so the traffic is going to Server 1 in each pool. In the event of a failure on Server 1, they'd like BOTH pools to fail to Server 2. Basically, they want to tie the "active" state of their pool members together, such that Server 1 in Pool 1 is always active with Server 1 in Pool 2. Likewise, if Server 1 fails in EITHER pool and traffic gets sent to Server 2, they'd like to have the other pool fail to Server 2.

 

 

This seems like something that could be solved with an iRule, but scouring around in the forums has produced very little for something like this. Any advice?

 

 

Thanks.

 

 

Joe

 

 

application delivery
dev
devops
iRules
  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    May 31, 2011
    Hi Joe,

     

     

    You can create a monitor with a hard coded destination address and/or port. If you create a monitor with the IP:port of server1 and assign that to server2, if server1 does down, server2 will also be marked down. You'll want to assign the server1 monitor to the server2 pool member--not the pool.

     

     

    Aaron
  • Colin_Walker_12's avatar
    Colin_Walker_12
    Historic F5 Account
    May 31, 2011
    If you were to go the iRules route you'd want to look at the LB::status command, but it'd get messy forcing pool member selection since you'd have to code in the member addresses somewhere. The monitor is likely a better route for this.

     

     

    Colin