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LeaV97_344716's avatar
LeaV97_344716
Icon for Nimbostratus rankNimbostratus
Dec 21, 2017

Priority Group Failback

I have a question similar to https://devcentral.f5.com/questions/priority-group-failback?rc=1 I have a group that has 4 different priority groups. Each group has 1 node. They want existing connections to drop when a higher priority is available again. They don't use the same priority on every port. The priority order is specific to each port. The iRule in the other question would work but, I'd have to write a different rule for each different priority order. Is there a way to write the iRule based on the priority group .

 

For example, if connected to anything but priority group 4 and the priority group 4 node is now available disconnect anything attached to 3, 2, or 1. If connected to group 2 or 1 and priority group 3 is available disconnect from group 2 or 1 and attach to group 3...

 

application delivery
iRules

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  • nitass's avatar
    nitass
    Icon for Employee rankEmployee
    Dec 23, 2017

    The iRule in the other question would work but, I'd have to write a different rule for each different priority order. Is there a way to write the iRule based on the priority group .

     

    i do not think you can use the irule patrick suggested since your traffic here is not http.

     

    for tcp traffic, client_accepted event is fired when tcp connection is established. to be able to control connection after establishing, we have to keep collecting and releasing data and when higher priority group member is back online, we drop or reject the existing connection. personally, i do not think this is a good idea.

     

    alternatively, we might be able to use user_alert.conf or icall to automatically disable lower priority group member when the higher group member is up.

     

    the other idea is to configure monitor to check higher priority group member but assign to the lower group member. so, when the higher group member is up, this monitor will make the lower group member down.

     

    for the 2nd and 3rd ideas, action on service down might also be needed.