[Varnish] #512: 503 error with load-balancer setup

Varnish varnish-bugs at projects.linpro.no
Wed May 27 09:39:31 CEST 2009

#512: 503 error with load-balancer setup
 Reporter:  ajung         |        Owner:  phk  
     Type:  defect        |       Status:  new  
 Priority:  high          |    Milestone:       
Component:  varnishd      |      Version:  trunk
 Severity:  major         |   Resolution:       
 Keywords:  Loadbalancer  |  
Comment (by whocares):

 The problem could be that you simply didn't wait long enough.

 In your configuration, Varnish would at least need 15 seconds (3 good
 replies with a wait time of 5 seconds between each try) before actually
 processing client requests. In the meantime it will reply with 503
 "Service Unavailable" because that's exactly what Varnish thinks is the

 As soon as you disable one of the .probe configs, Varnish will see the
 node with the probes disabled as immediately available and start serving
 requests from there until the second backend is successfully checked and
 also used in the loadbalancing setup. That's why it works for you when
 just checking one backend system.

Ticket URL: <http://varnish.projects.linpro.no/ticket/512#comment:1>
Varnish <http://varnish.projects.linpro.no/>
The Varnish HTTP Accelerator

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