Forum Discussion

paul_adomeit_70's avatar
paul_adomeit_70
Icon for Nimbostratus rankNimbostratus
Sep 28, 2006

Round Robin two pools

We were asked to balance four servers in a pretty unique way. The way to make it behave like it was requested would be to create two pools with all four members but have different priorities assigned so that for any one pool, only one server would be selected and only two total severs at a time would take traffic. We've written some pretty scarry iRules but I'm not sure how to write a rule that just round robin's two pools without looking for something first. Two VIP's is not an option, a single pool with priority activation would not work. We could make this happen by querying the node status's and build our logic around that but we like simple. Any simple ideas?

 

-p
application delivery
dev
devops
iRules

4 Replies

Sort By
  • Joe_Pruitt's avatar
    Joe_Pruitt
    Sep 29, 2006
    Something like this should do the trick...

    when RULE_INIT {
  set ::NEXT_POOL 0  
}
when CLIENT_ACCEPTED {
  if { $::NEXT_POOL == 0 } {
    pool pool_a
    set ::NEXT_POOL 1
  } else {
    pool pool_b
    set ::NEXT_POOL 0
  }
}

    This creates a global variable "NEXT_POOL" and then on each connection it toggles the pool to use.

    I don't know how to get away without making use of a global variable.

    -Joe
  • paul_adomeit_70's avatar
    paul_adomeit_70
    Icon for Nimbostratus rankNimbostratus
    Oct 03, 2006
    Joe,

     

    Thank you very much. This works just fine plus I got to learn just a little bit more. Neat stuff.

     

    -p

     

  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Nov 30, 2006
    You would want to add persistence in the rule. One option is to use cookie insert based on the pool selected. Here is an example: (Click here)

     

     

    Aaron