iRule to isolate node

Should corporate users use the secondary nodes if the primary node is offline?

If so, I would create two separate pools - one with all pool members (primary and secondary) using priority group activation to use the primary server if it's available, and another pool that only contains secondary nodes.

The iRule would be very similar:

when CLIENT_ACCEPTED {
if { [IP::addr [IP::client_addr] equals 38.1.0.1] } {
  pool primary-secondary_pool
}
else {
  pool secondary_pool
}
}