<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style>
</head>
<body dir="ltr">
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Hi,</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
This is part of my varnish configuration file for sharding:</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
```</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<div>cat /etc/varnish/default.vcl </div>
<div><br>
</div>
<div>vcl 4.1;</div>
<div><br>
</div>
<div>import directors;</div>
<div><br>
</div>
<div><br>
</div>
<div>probe myprobe {</div>
<div> .request =</div>
<div> "HEAD /healthcheck.php HTTP/1.1"</div>
<div> "Connection: close"</div>
<div> "User-Agent: Varnish Health Probe";</div>
<div> .timeout = 1s;</div>
<div> .interval = 5s;</div>
<div> .window = 5;</div>
<div> .threshold = 3;</div>
<div>}</div>
<div><br>
</div>
<div><br>
</div>
<div>backend b-01 { .host = "b-01"; .port = "80"; .probe = myprobe; }</div>
<div>backend b-02 { .host = "b-02"; .port = "80"; .probe = myprobe; }</div>
<div>backend b-03 { .host = "b-03"; .port = "80"; .probe = myprobe; }</div>
<div><br>
</div>
<div><br>
</div>
<div>sub vcl_init {</div>
<div><br>
</div>
<div><br>
</div>
<div> new hls_cluster = directors.shard();</div>
<div> hls_cluster.add_backend(b-01);</div>
<div> hls_cluster.add_backend(b-02);</div>
<div> hls_cluster.add_backend(b-03);</div>
<div><br>
</div>
<div><br>
</div>
<div> new p = directors.shard_param();</div>
<div> </div>
<div> hls_cluster.set_rampup(30s); </div>
<div># hls_cluster.set_warmup(0.5);</div>
<div><br>
</div>
<div> hls_cluster.reconfigure();</div>
<div> hls_cluster.associate(p.use());</div>
<div><br>
</div>
<div>}</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div>acl purge {</div>
<div> "localhost";</div>
<div>}</div>
<div><br>
</div>
<div><br>
</div>
<div>sub vcl_recv {</div>
<div><br>
</div>
<div> set req.backend_hint = hls_cluster.backend();</div>
<div><br>
</div>
<div>}</div>
<div><br>
</div>
<div><br>
</div>
<div>sub vcl_backend_fetch {</div>
<div><br>
</div>
<div> p.set(by=KEY, key=hls_cluster.key(bereq.url));</div>
<div> set bereq.backend = hls_cluster.backend(resolve=LAZY, healthy=CHOSEN);</div>
<div><br>
</div>
<div>}</div>
<div><br>
</div>
<div>```</div>
1. there are two set backend in this config, one is on vcl_recv:</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
"set req.backend_hint = hls_cluster.backend();"</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
and one in vcl_backend_fetch:</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
"set bereq.backend = hls_cluster.backend(resolve=LAZY, healthy=CHOSEN);"</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
should I remove set in vcl_recv cause I think if I adjust it , all requset will go through this backend list and configs like healthy=CHOSEN in vcl_backend_fetch wouldnt be applied! Am I true?</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
2.Actually what is difference between vcl_backend_fetch and vcl_recv?</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
3.should I remove "set req.backend_hint" from vcl_recv?</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Best regards,Hamidreza<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
</body>
</html>