What are the steps to problem solve when all I can get are 503s?

Jacques whshub at gmail.com
Sun Jul 11 19:54:41 CEST 2010


I tried using a local server and using a vcl rather than command line
parameters to define the backend.  I still only get 503s.  Is there a way to
better debug Varnish so that I can determine why it can't make a backend
connection?

Thanks,
Jacques

On Sat, Jul 10, 2010 at 12:47 AM, Jorge Díaz <jdzstz at gmail.com> wrote:

> It seems for some reason Varnish cannot connect to backend.
>
> I have never used parameter " -b 87.238.47.204:80 <http://87.238.47.204/> "
> for backend configuration.
>
> You sould try creating a little VCL configuration file.
>  Modify default.vcl adding the backend in it, and start varnish with
> parameter -f
>
> -f /opt/extra/etc/varnish/default.vcl
>
> Inside VCL, configure the backed with:
>
> backend default {
>     .host = "87.238.47.204";
>     .port = "80";
> }
>
> If the problem persist, a good idea is to install a Apache webserver in localhost and try It as backend, for example in 127.0.0.1 port 8000
>
> in order to see if the problem is varnish connecting to a remote IP or is varnish that not connect to nobody.
>
> My varnish installation is in same host of Apache webserver and works OK.
>
>
> Regards.
>
>
> 2010/7/9 Jacques <whshub at gmail.com>
>
> I'm not currently using a vcl, just configuring via the command line for
>> simplicity.  Adding the connect_timeout parameter below had no impact on the
>> 503s.  Nor did adding all the parameters listed at letsdugg.com.
>>
>> Communication with the external server works perfectly.  (Telnet and via
>> lynx.)  It's actually the varnish-cache.org site just to introduce a
>> minimum number of variables.
>>
>> The only thing that I see in the varnish log is the FetchError, no backend
>> connection.
>>
>> Here is a startup, request, shutdown cycle of varnish log:
>>
>> # /opt/extra/bin/varnishlog
>>     0 WorkThread   - fffffd7ff9dc0d20 start
>>     0 CLI          - Rd vcl.load "boot" ./vcl.ORk8t3RP.so
>>     0 CLI          - Wr 200 Loaded "./vcl.ORk8t3RP.so" as "boot"
>>     0 CLI          - Rd vcl.use "boot"
>>     0 CLI          - Wr 200
>>     0 CLI          - Rd start
>>     0 Debug        - "Acceptor poll space increased to 512"
>>     0 Debug        - "Acceptor is poll"
>>     0 CLI          - Wr 200
>>     0 WorkThread   - fffffd7ff93c5d20 start
>>     0 WorkThread   - fffffd7ff91c6d20 start
>>     0 WorkThread   - fffffd7ff8fc7d20 start
>>     0 WorkThread   - fffffd7ff8dc8d20 start
>>     0 WorkThread   - fffffd7ff8bc9d20 start
>>     0 WorkThread   - fffffd7ff89cad20 start
>>     0 WorkThread   - fffffd7ff87cbd20 start
>>     0 WorkThread   - fffffd7ff85ccd20 start
>>     0 WorkThread   - fffffd7ff83cdd20 start
>>     0 CLI          - Rd ping
>>     0 CLI          - Wr 200 PONG 1278687217 1.0
>>     0 CLI          - Rd ping
>>     0 CLI          - Wr 200 PONG 1278687220 1.0
>>     9 SessionOpen  c 10.100.200.1 64024 :80
>>     9 ReqStart     c 10.100.200.1 64024 1455837036
>>     9 RxRequest    c GET
>>     9 RxURL        c /
>>     9 RxProtocol   c HTTP/1.0
>>     9 RxHeader     c Host: 10.100.200.2
>>     9 RxHeader     c Accept: text/html, text/plain, text/css, text/sgml,
>> */*;q=0.01
>>     9 RxHeader     c Accept-Encoding: gzip, compress, bzip2
>>     9 RxHeader     c Accept-Language: en
>>     9 RxHeader     c User-Agent: Lynx/2.8.6rel.5 libwww-FM/2.14
>> SSL-MM/1.4.1 OpenSSL/0.9.8l
>>     9 VCL_call     c recv
>>     9 VCL_return   c lookup
>>     9 VCL_call     c hash
>>     9 VCL_return   c hash
>>     9 VCL_call     c miss
>>     9 VCL_return   c fetch
>>     9 FetchError   c no backend connection
>>     9 VCL_call     c error
>>     9 VCL_return   c deliver
>>     9 Length       c 488
>>     9 VCL_call     c deliver
>>     9 VCL_return   c deliver
>>     9 TxProtocol   c HTTP/1.1
>>     9 TxStatus     c 503
>>     9 TxResponse   c Service Unavailable
>>     9 TxHeader     c Server: Varnish
>>     9 TxHeader     c Retry-After: 0
>>     9 TxHeader     c Content-Type: text/html; charset=utf-8
>>     9 TxHeader     c Content-Length: 488
>>     9 TxHeader     c Date: Fri, 09 Jul 2010 14:53:42 GMT
>>     9 TxHeader     c X-Varnish: 1455837036
>>     9 TxHeader     c Age: 0
>>     9 TxHeader     c Via: 1.1 varnish
>>     9 TxHeader     c Connection: close
>>     9 ReqEnd       c 1455837036 1278687222.201183081 1278687222.201552391
>> 0.000498056 0.000254393 0.000114918
>>     9 SessionClose c error
>>     9 StatSess     c 10.100.200.1 64024 0 1 1 0 0 0 235 488
>>     0 CLI          - Rd ping
>>     0 CLI          - Wr 200 PONG 1278687223 1.0
>>     0 CLI          - Rd ping
>>     0 CLI          - Wr 200 PONG 1278687226 1.0
>>     0 CLI          - Rd ping
>>     0 CLI          - Wr 200 PONG 1278687229 1.0
>>
>>
>>
>>
>>
>>
>> On Fri, Jul 9, 2010 at 12:58 AM, Jorge Díaz <jdzstz at gmail.com> wrote:
>>
>>> ¿There is communication between Varnish host and 87.238.47.204 machine??
>>>
>>> Try first making " telnet 87.238.47.204 80 " in order testing there is no
>>> firewall or a rule configured in webserver.
>>>
>>> If comunication is fine, the problem must be in VCL configuration. Try
>>> executing varnishlog while you are testing and look for errors in output.
>>>
>>> In Solaris is also important to run Varnish with proper parameter that
>>> are listen in:
>>>
>>>    - http://letsgetdugg.com/2009/12/04/varnish-on-solaris/
>>>
>>>
>>> I had a lot of comunication problems without parameter:
>>>
>>>       * -p connect_timeout=0s         # Important bug work around for Solaris*
>>>
>>>
>>>
>>>
>>>
>>> 2010/7/9 Bedis 9 <bedis9 at gmail.com>
>>>
>>> Hey,
>>>>
>>>> Can you share your VCL conf?
>>>>
>>>> cheers
>>>>
>>>> On Fri, Jul 9, 2010 at 7:08 AM, Jacques <whshub at gmail.com> wrote:
>>>>
>>>>> I am trying to use Varnish on OpenSolaris.  Due the help of others, I
>>>>> have versions compiling and not crashing that are based on three different
>>>>> versions of Varnish.
>>>>>
>>>>> I'm using 4516, 2.1.2 with the 649 patch, and trunk.   I've also tried
>>>>> compiling with gcc 4.3.3 in addition to the OpenSolaris standard of 3.4.3.
>>>>>  That changed nothing.
>>>>>
>>>>> All compiled copies of varnish seem to start just fine.  I can use
>>>>> varnishlog and see my requests arriving at Varnish.
>>>>>
>>>>> However, responses are always 503 with " FetchError: no backend
>>>>> connection".  Using tcpdump, I see no calls to the backend server from
>>>>> Varnish, ever.
>>>>>
>>>>> For simplicity, I'm using the basic start of:
>>>>>
>>>>> varnishd -a :80 -b 87.238.47.204:80
>>>>>
>>>>> What are right steps to determine what is wrong?  I see nothing in
>>>>> syslogs.  Varnish doesn't complain.  Using all the same steps on ubuntu, I
>>>>> get exactly what I expect, a cached version of the backend server.
>>>>>
>>>>> Any pointers about how I should figure out what is failing would be
>>>>> helpful.
>>>>>
>>>>> Thanks,
>>>>> Jacques
>>>>>
>>>>> I've also noticed that the cache is starting at 500GB.  Changing the
>>>>> cache size to 512MB didn't have any impact on the 503s.
>>>>>
>>>>> _______________________________________________
>>>>> varnish-misc mailing list
>>>>> varnish-misc at varnish-cache.org
>>>>> http://lists.varnish-cache.org/mailman/listinfo/varnish-misc
>>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> varnish-misc mailing list
>>>> varnish-misc at varnish-cache.org
>>>> http://lists.varnish-cache.org/mailman/listinfo/varnish-misc
>>>>
>>>
>>>
>>
>
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