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Local Dir 417 with HTTP Probes fail to recover.

Having some trouble with the setup of a Local Director 417 using http probes to test the functionality of an underlying database.

The symptoms are as follows:

2 real servers and 1 virtual. Http-probes sent with a 20 second interval. If one real server is taken down - the LD keeps probing the server every 20 seconds and brings it up if/when the probe succeeds.

However - if BOTH the real servers are taken down - in a few seconds the virtual server is also marked as down (naturally). But here is the problem - as the virtual server is marked as down the LD stops sending HTTP probes onto the real servers, thereby making automatic recovery impossible....

In this state I can of course just bring one of the real servers up with the "in-service" command. The virtual server then comes up and it starts sending probes to BOTH servers again.

So to summarize my problem: How can I accomplish automatic recovery when both my real servers are taken down (lets say for backup) using HTTP probes?

Relevant config and debug below.

Best regards

Johan S

ip address 10.46.x.121 255.255.255.0

arp timeout 30

no rip passive

rip version 1

failover ip address 0.0.0.0

no failover

failover hellotime 30

password xxxxxxxxxxxxxxxx encrypted

virtual 10.46.x.120:0:0:tcp is

real 10.46.x.12:0:0:tcp is

real 10.46.x.13:0:0:tcp is

name 10.46.x.12 real1

name 10.46.x.13 real2

name 10.46.x.120 virtual

bind 10.46.x.120:0:0:tcp 10.46.x.12:0:0:tcp

bind 10.46.x.120:0:0:tcp 10.46.x.13:0:0:tcp

probe virtual 10.46.x.120:0:0:tcp http 2

probe real 10.46.x.12:0:0:tcp http 2

probe real 10.46.x.13:0:0:tcp http 2

probehttp virtual 10.46.x.120:0:0:tcp file /probe/probedb.html

probehttp real 10.46.x.12:0:0:tcp file /probe/probedb.html

probehttp real 10.46.x.13:0:0:tcp file /probe/probedb.html

probeconfig http 1

Some Debug:

Real Machines:

No Answer TCP Reset DataIn

Machine Connect State Thresh Reassigns Reassigns Conns

real1:0:0:tcp 0 IS 8 0 0 0

real2:0:0:tcp 2 IS 8 0 0 0

BOTH TAKEN DOWN

localdirector(config)# <163> July 8 17:17:02 LD-ERR Real machine 'real1:0:0:tcp': edited fr

om In service to Failed (External) -- Probe.

s<163> July 8 17:17:02 LD-ERR Real machine 'real2:0:0:tcp': edited from In serhvice to Fail

ed (External) -- Probe.

real

Real Machines:

No Answer TCP Reset DataIn

Machine Connect State Thresh Reassigns Reassigns Conns

real1:0:0:tcp 0 EFAILED 8 0 0 0

real2:0:0:tcp 1 EFAILED 8 0 0 0

A FEW SECONDS LATER THE VIRTUAL SERVER FAILS - NO MORE HTTP PROBES

localdirector(config)# <162> July 8 17:17:21 LD-CRIT Virtual machine 'virtual:0:0:tcp': Failed

.

localdirector(config)# sh real

Real Machines:

No Answer TCP Reset DataIn

Machine Connect State Thresh Reassigns Reassigns Conns

real1:0:0:tcp 0 EFAILED 8 0 0 0

real2:0:0:tcp 0 EFAILED 8 0 0 0

localdirector(config)# sh virt

Machines:

Machine Mode State Connect Sticky Predictor Slowstar

t

virtual:0:0:tcp directed local FAILED 0 0 leastconns* roundro

bin

NOW THE SERVERS ARE UP - BUT NO PROBES ARE SENT - THE REAL SERVERS REMAIN IN EFAILED (NOT IN "TESTING")

BRING ONE SERVER UP MANUALLY -THE PROBES CONTINUE - SERVICE RESTORED

localdirector(config)# is real real1

l<165> July 8 17:20:18 LD-NOTICE Real machine 'real1:0:0:tcp': Edited from Faioled (Externa

l) to In Service.

c<162> July 8 17:20:18 LD-CRIT Switching '10.46.x.120:0:0:tcp' from 'leastconnsa' to 'slowst

art'

ldirector(config)# <162> July 8 17:20:19 LD-CRIT Switching '10.46.x.120:0:0:tcp' from 'slows

tart' to 'leastconns'

<162> July 8 17:20:19 LD-CRIT Virtual machine 'virtual:0:0:tcp': Brought into service.

<163> July 8 17:20:42 LD-ERR Real machine 'real2:0:0:tcp': edited from Failed (External) to

Testing - HTTP probes.

<163> July 8 17:21:02 LD-ERR Real machine 'real2:0:0:tcp': edited from Testing to In Servic

e - HTTP probes.

1 REPLY
New Member

Re: Local Dir 417 with HTTP Probes fail to recover.

I found the answer myself - so I'm posting this to help others who get stuck with the same problem.

Turns out this is a bug in version 4.2.1 and is resolved in 4.2.3.

Cheers

Johan

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