priority LB - maybe better suited to iRule?

Thanks for the tips ... just getting my head around these irules. With the logging turned on i can see that "if statment" is using the failover pool and not the main_pool. I have main_pool defined in my virtual.

The only way I can get the "begin:" log to show "main_pool" is to define the pool:

when LB_FAILED {
pool main_pool
log local0. "begin: pool [LB::server pool], active mbrs = [active_members [LB::server pool]]"
if { ( [LB::server pool] eq "main_pool" ) and ( [active_members main_pool] == 0 ) } {
      pool failover_pool
      persist none
      LB::reselect
      log local0. "end: pool [LB::server pool], active mbrs = [active_members [LB::server pool]]"
    }
}

With the above rule I see these logs when the nodes in main_pool are all inactive:

Dec  7 08:10:45 tmm tmm[714]: Rule domain.com-failover : begin: pool main_pool, active mbrs = 0
Dec  7 08:10:45 tmm tmm[714]: Rule domain.com-failover : end: pool failover_pool, active mbrs = 3

For clarity - this is what I see without defining the pool (and failover_pool nodes not served if main_pool nodes inactive:

when LB_FAILED {
log local0. "begin: pool [LB::server pool], active mbrs = [active_members [LB::server pool]]"
if { ( [LB::server pool] eq "main_pool" ) and ( [active_members main_pool] == 0 ) } {
      pool failover_pool
      persist none
      LB::reselect
      log local0. "end: pool [LB::server pool], active mbrs = [active_members [LB::server pool]]"
    }
}

logs:

Dec  7 08:12:58 tmm tmm[714]: Rule domain.com-failover : begin: pool failover_pool, active mbrs = 3
Dec  7 08:12:58 tmm tmm[714]: Rule domain.com-failover : begin: pool failover_pool, active mbrs = 3