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

Jorge Díaz jdzstz at gmail.com
Sat Jul 10 09:47:42 CEST 2010


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
>>>
>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.varnish-cache.org/pipermail/varnish-misc/attachments/20100710/fe94310f/attachment.html>


More information about the varnish-misc mailing list