Action On Service Down vs LB::reselect

Action on Service Down mainly effects existing connections to the server going down. You have three options - do nothing, send a reset to the client, rebind the connection to another server.

 

 

LB::reselect can be used when the initial connection to a server does not connect (EG: in the LB_FAILED event). This allows you to override the destination of the incoming connection upon a failure - not reselecting will result in a reset to the client.

 

 

So, these two methods apply to different situations and aren't mutually exclusion.

 

 

HTH.

What occurs after the LB::reselect in the LB_FAILED event? Does it just reselect a server, or does it retrigger any of the prior events? I am trying to account for clients who don't allow cookies with this rule (I am using cookie insert persistence on the virtual as well)

when HTTP_RESPONSE {
  if { [HTTP::cookie exists "JSESSIONID"] } {
    set trimID [lindex [split  [HTTP::cookie "JSESSIONID"] "!" ] 0 ]
    if { [session lookup uie $trimID] equals "" } {
      session add uie $trimID [IP::server_addr] 1800
      log "added server entry [session lookup uie $trimID] for jsessionID $trimID "
    } else {
      log "existing server entry [session lookup uie $trimID] for jsessionID $trimID"
    }
  }
}
when HTTP_REQUEST {
  if { [active_members MyPool] == 0 } {
    HTTP::redirect "http://[HTTP::header "X-Forwarded-Host"]/unavailable/unavailable.html"
  }
  if { [HTTP::header exists "X-Forwarded-Host"] } {
    HTTP::header replace "Host" [HTTP::header "X-Forwarded-Host"]
  }
  if { not [HTTP::cookie exists "MyCookie"] } {
    if {  [findstr [HTTP::uri] "jsessionid" 11 "!"]  != "" } {
      pool MyPool member [session lookup uie [findstr [HTTP::uri] "jsessionid" 11 "!"] ]
      log "jsessionID [findstr [HTTP::uri] "jsessionid" 11 "!"] sent to [session lookup uie [findstr [HTTP::uri] "jsessionid" 11 "!"] ]"
    } else {
      if { [HTTP::cookie exists "JSESSIONID"] } {
        log "used Cookie Insert, value is [HTTP::cookie "MyCookie"]"
      }
    }
  }
}
when LB_FAILED {
  LB::reselect pool MyPool
  LB::reselect
  log "server reselected due to failure!"
}

I am getting this error after the server fails:

Jul 10 11:24:20 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : server reselected due to failure!

Jul 10 11:24:20 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : server reselected due to failure!

Jul 10 11:24:20 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : server reselected due to failure!

Jul 10 11:24:20 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : server reselected due to failure!

Jul 10 11:24:20 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : server reselected due to failure!

Jul 10 11:24:23 tmm tmm[11686]: 01220002: repeated 56300 times

My problem is that the pool member is set by the value in the session table, and the LB::reselect doesn't seem to reselect anything other than the failed instance. I have 16 members in the pool, all up except the instance we failed for testing. Any ideas?

I added some additional logging to confirm the same server is being selected, even though there are 15 other servers that could be tried:

 

 

 

Jul 10 12:08:01 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : server reselected 10.28.199.183

 

Jul 10 12:08:02 tmm tmm[11686]: 01220002: repeated 2 times

 

Jul 10 12:08:03 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : jsessionID GylyPWny1tJKRwp1jlvvd3Kp5DH CYThCcJS2Y2JrlNhrMtB6GcJG sent to 10.28.199.183

 

Jul 10 12:08:03 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : server reselected 10.28.199.183

 

Jul 10 12:08:03 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : jsessionID GylyPWny1tJKRwp1jlvvd3Kp5DH CYThCcJS2Y2JrlNhrMtB6GcJG sent to 10.28.199.183

 

Jul 10 12:08:03 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : server reselected 10.28.199.183

 

Jul 10 12:08:06 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : jsessionID GylyPWny1tJKRwp1jlvvd3Kp5DH CYThCcJS2Y2JrlNhrMtB6GcJG sent to 10.28.199.183

 

Jul 10 12:08:06 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : server reselected 10.28.199.183

 

Jul 10 12:08:07 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : server reselected 10.28.199.183

 

Jul 10 12:08:07 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : server reselected 10.28.199.183

 

Jul 10 12:08:07 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : server reselected 10.28.199.183

 

Jul 10 12:08:07 tmm tmm[11686]: 01220002:6: Rule intres_prod-rule : server reselected 10.28.199.183

 

Jul 10 12:08:08 tmm tmm[11686]: 01220002: repeated 47 times

 

 

 

I would imagine the above HTTP_REQUEST events are client retries, not events retriggered by the LB::reselect, correct? How do I get it to reselect another server?

 

 

Also, I though once a node was marked down anything in the session table associated to that node was flushed?

Any luck on this issue? I'm having the same (or very similar) problem.