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Roman_80473's avatar
Roman_80473
Icon for Nimbostratus rankNimbostratus
Nov 17, 2011

Detect if node is half-dead with an iRule?

Hi folks,     I was tasked to monitor app servers in the pool with an iRule (LTM 10.2). I wrote a simple rule which does the following:   if I get into LB_FAILED, I take the node out and res...
application delivery
dev
devops
iRules
nitass's avatar
nitass
Icon for Employee rankEmployee
Nov 18, 2011
if i put LB::detach before LB::reselect, tcl was not error but after sending fin, bigip did not establish connection to pool foo2. i think because bigip already established connection to pool foo. 

[root@ve1023:Active] config  b rule myrule list
rule myrule {
   when RULE_INIT {
        set static::response_timeout  5
}

when HTTP_REQUEST {
        log local0. "Received request, beginning response monitor interval. [clock seconds]"
}

when LB_SELECTED {
        set monitor_id [\
                after $static::response_timeout {
                        LB::detach
                        LB::reselect pool foo2
                        log local0. "Timeout $static::response_timeout milliseconds elapsed without server response. [clock seconds]"
                }\
        ]
}

when HTTP_RESPONSE {
        log local0. "Received server response."
        if {[info exists monitor_id]} {
                log local0. "Canceling after script with id $monitor_id"
                after cancel $monitor_id
        }
}
}

 curl -i http://172.28.19.79
...no response...

Nov 18 00:27:41 local/tmm info tmm[4766]: Rule myrule : Received request, beginning response monitor interval. 1321604861
Nov 18 00:27:41 local/tmm info tmm[4766]: Rule myrule : Timeout 5 milliseconds elapsed without server response. 1321604861

00:27:41.513841 IP 172.28.19.253.47126 > 172.28.19.79.80: S 2431649126:2431649126(0) win 5840 
00:27:41.513884 IP 172.28.19.79.80 > 172.28.19.253.47126: S 3818007430:3818007430(0) ack 2431649127 win 4380 
00:27:41.517039 IP 172.28.19.253.47126 > 172.28.19.79.80: . ack 1 win 46 
00:27:41.517091 IP 172.28.19.253.47126 > 172.28.19.79.80: P 1:155(154) ack 1 win 46 
00:27:41.517268 IP 200.200.200.10.47126 > 200.200.200.101.88: S 1242901181:1242901181(0) win 4380 
00:27:41.517934 IP 200.200.200.101.88 > 200.200.200.10.47126: S 3205360631:3205360631(0) ack 1242901182 win 5792 
00:27:41.517946 IP 200.200.200.10.47126 > 200.200.200.101.88: . ack 1 win 4380 
00:27:41.517957 IP 200.200.200.10.47126 > 200.200.200.101.88: P 1:155(154) ack 1 win 4380 
00:27:41.518888 IP 200.200.200.101.88 > 200.200.200.10.47126: . ack 155 win 54 
00:27:41.522163 IP 200.200.200.10.47126 > 200.200.200.101.88: F 155:155(0) ack 1 win 4380 
00:27:41.522884 IP 200.200.200.101.88 > 200.200.200.10.47126: F 1:1(0) ack 156 win 54 
00:27:41.522899 IP 200.200.200.10.47126 > 200.200.200.101.88: . ack 2 win 4380 
00:27:41.617423 IP 172.28.19.79.80 > 172.28.19.253.47126: . ack 155 win 4534