[Varnish] #407: Documentation : the restart sample does not work if the backend is dead

[Varnish]

#407: Documentation : the restart sample does not work if the backend is dead
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 Reporter:  jfbubus  |        Type:  documentation
   Status:  new      |    Priority:  normal       
Milestone:           |   Component:  documentation
  Version:  trunk    |    Severity:  normal       
 Keywords:           |  
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 The VCLExampleRestarts sample does not work if the backend is away.

 It works better using probes & health checking :
 {{{
 backend b1 {
         .host = "fs.freebsd.dk";
         .port = "82";
         .probe = {
                 .url = "/probe.cgi";
                 .timeout = 34 ms;
                 .interval = 1s;
                 .window = 10;
                 .threshold = 8;
         }
 }
 backend b2 {
         .host = "fs.freebsd.dk";
         .port = "81";
         .probe = {
                 .url = "/probe.cgi";
                 .timeout = 34 ms;
                 .interval = 1s;
                 .window = 10;
                 .threshold = 8;
         }
 }
 backend b3 {
         .host = "fs.freebsd.dk";
         .port = "80";
         .probe = {
                 .url = "/probe.cgi";
                 .timeout = 34 ms;
                 .interval = 1s;
                 .window = 10;
                 .threshold = 8;
         }
 }

 sub vcl_recv {
         set req.backend = b1;
         if (req.restarts == 1 || !req.backend.healthy) {
                 set req.backend = b2;
         }
         if (req.restarts == 2 || !req.backend.healthy) {
                 set req.backend = b3;
         }
 }

 sub vcl_fetch {
         ## If the request to the backend returns a code other than 200,
 restart the loop
         ## If the number of restarts reaches the value of the parameter
 max_restarts,
         ## the request will be error'ed.  max_restarts defaults to 4.
 This prevents
         ## an eternal loop in the event that, e.g., the object does not
 exist at all.
         if (obj.status != 200 && obj.status != 403 && obj.status != 404) {
                 restart;
         }
 }
 }}}

-- 
Ticket URL: <http://varnish.projects.linpro.no/ticket/407>
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