iRule to disable a pool to new connections

Note: Calling LB::down in an iRule triggers an immediate monitor probe regardless of the monitor interval settings.

Fair enough. So then you have a few more options:

1. Ignore the log statements

2. Turn down logging

3. Add another log statement just before LB::down to indicate that next statements are by design

4. Use the user_alert method

5. Send users to a different pool during the down period (same members minus the ones you want to remove). Here's an iRule example of what that might look like:

   when RULE_INIT {
        user-defined: start of DOWN time
       set static::START_OFF_TIME "06:33 AM"
        user-defined: end of DOWN time
       set static::END_OFF_TIME "10:00 AM"
        user-defined: DOWN pool
       set static::DOWN_POOL "local-pool-minus2"
   }
   when CLIENT_ACCEPTED {
        get pool assigned to the VIP (and strip off partition)
       set default_pool [string map {"/Common/" ""} [LB::server pool]]
        recreate the persistence cookie name
       set persistcookie "BIGipServer${default_pool}"
   }
   when HTTP_REQUEST {
       set start_off_time [clock scan $static::START_OFF_TIME]
       set end_off_time [clock scan $static::END_OFF_TIME]
       set now [clock seconds]
   
        if the persistence cookie doesn't exists, and inside DOWN time - send to DOWN pool
       if { not ( [HTTP::cookie exists $persistcookie] ) and (( [expr $now > $start_off_time] ) and ( [expr $now < $end_off_time] )) } {
           pool $static::DOWN_POOL
       } 
   }
   

First, set a default cookie persistence profile on the VIP. If the request is made by a new user (with no existing persistence cookie) during the down period, send them to the designated DOWN pool. If a user has an existing session (has a persistence cookie for the default pool), continue to send them to the default pool. This will allow you to remove the servers without disrupting existing sessions.