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<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">Have you tried with a correct example of DNS director ?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">e.g. from </span><span lang="EN-GB">The
<a href="https://www.varnish-cache.org/docs/3.0/reference/vcl.html#the-dns-director">
Varnish Reference Manual</a> :</span><span lang="EN-US" style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
<div style="mso-element:para-border-div;border-top:solid #AACC99 1.0pt;border-left:none;border-bottom:solid #AACC99 1.0pt;border-right:none;padding:4.0pt 0cm 4.0pt 0cm;background:#EEFFCC">
<p class="MsoNormal" style="line-height:11.25pt;background:#EEFFCC;border:none;padding:0cm">
<span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";color:#222222;mso-fareast-language:FR">director directorname dns {<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.25pt;background:#EEFFCC;border:none;padding:0cm">
<span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";color:#222222;mso-fareast-language:FR"> .list = {<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.25pt;background:#EEFFCC;border:none;padding:0cm">
<span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";color:#222222;mso-fareast-language:FR"> .host_header = "www.example.com";<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.25pt;background:#EEFFCC;border:none;padding:0cm">
<span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";color:#222222;mso-fareast-language:FR"> .port = "80";<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.25pt;background:#EEFFCC;border:none;padding:0cm">
<span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";color:#222222;mso-fareast-language:FR"> .connect_timeout = 0.4s;<o:p></o:p></span></p>
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<span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";color:#222222;mso-fareast-language:FR"> "192.168.15.0"/24;<o:p></o:p></span></p>
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<span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";color:#222222;mso-fareast-language:FR"> "192.168.16.128"/25;<o:p></o:p></span></p>
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<span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";color:#222222;mso-fareast-language:FR"> }<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height:11.25pt;background:#EEFFCC;border:none;padding:0cm">
<span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";color:#222222;mso-fareast-language:FR"> .ttl = 5m;<o:p></o:p></span></p>
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<span lang="EN-US" style="font-size:10.0pt;font-family:"Courier New";color:#222222;mso-fareast-language:FR">
</span><span style="font-size:10.0pt;font-family:"Courier New";color:#222222;mso-fareast-language:FR">.suffix = "internal.example.net";<o:p></o:p></span></p>
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<span style="font-size:10.0pt;font-family:"Courier New";color:#222222;mso-fareast-language:FR">}<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">Varnish need to know in advance the range of IPs, else, it will not be working.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">I think latest version of Varnish will improve this kind of ability by implementing lazy backend creation. But I’m not sure if it’s stable enough to be used.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
<div>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:9.0pt;font-family:"Arial","sans-serif";color:#666666;mso-fareast-language:FR">Jonathan Huot<o:p></o:p></span></b></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Arial","sans-serif";color:#666666;mso-fareast-language:FR">Phone: +33(0)1.47.62.78.65<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";mso-fareast-language:FR">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif";mso-fareast-language:FR"> varnish-bugs-bounces+jonathan.huot=thomsonreuters.com@varnish-cache.org
[mailto:varnish-bugs-bounces+jonathan.huot=thomsonreuters.com@varnish-cache.org]
<b>On Behalf Of </b>Tim Harrison<br>
<b>Sent:</b> Thursday, 22 August 2013 08:11 PM<br>
<b>To:</b> varnish-bugs@varnish-cache.org<br>
<b>Subject:</b> DNS Director with hostname resolving to multiple IPs<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-GB">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">The <a href="https://www.varnish-cache.org/docs/3.0/reference/vcl.html#the-dns-director">
Varnish Reference Manual</a> suggests that the DNS director can be used with a hostname that resolves to multiple IP addresses,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-indent:36.0pt"><i><span lang="EN-GB">“DNS round robin balancing is supported. If a hostname resolves to multiple backends, the director will divide the traffic between all of them in a round-robin manner.”<o:p></o:p></span></i></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">And I believe the following is the correct VCL to implement this,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Courier New"">director test dns {<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Courier New""> {<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Courier New""> .backend = {<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Courier New""> .host = "hostname.with.multiple.ips";<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Courier New""> }<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Courier New""> }<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Courier New""> .ttl = 10s;<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Courier New"">}<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">However, on compilation Varnish complains,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Courier New"">Backend host "hostname.with.multiple.ips": resolves to multiple IPv4 addresses.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Courier New"">Only one address is allowed.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Courier New"">Please specify which exact address you want to use, we found these:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Courier New""> xxx.xxx.xxx.xxx<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="font-family:"Courier New""> xxx.xxx.xxx.xxx<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Having looked at the source code in vcc_dir_dns.c and vcc_backend.c, it seems that the hostname associated with a
</span><span lang="EN-GB" style="font-family:"Courier New"">.host</span><span lang="EN-GB"> object can never resolve to more than one IP address, so it’s not clear how the functionality described in the Reference Manual can be achieved.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">I think this may be a bug, can you help please?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Many thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="mso-fareast-language:EN-GB">Tim Harrison</span><span lang="EN-GB"><o:p></o:p></span></p>
<p class="b5106d6a-14db-4c5e-b594-6a7a4117503b"><span lang="EN-GB"> <o:p></o:p></span></p>
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