Varnish 503 on POST requests once in a while

Dridi Boukelmoune dridi at varni.sh
Fri Dec 27 07:45:17 UTC 2019


On Fri, Dec 27, 2019 at 1:00 AM Maninder Singh <mandys at gmail.com> wrote:
>
> I only have php-fpm slow logging for requests greater than 5secs. Otherwise it should be all defaults for varnish/apache/fpm.
>
> Does varnish or apache have anything defaulting to 5secs?

timeout_idle defaults to 5s

> Otherwise fpm might be closing the connection for logging a slow request ? Strange?
>
> On Thu, 26 Dec, 2019, 10:44 pm Guillaume Quintard, <guillaume at varnish-software.com> wrote:
>>
>> The first looks like the backend is just closing the door on you. The other one (Resource temporarily unavailable), because of the Timestamp:Beresp,  is most probably a timeout (did you set anything to 5s?)
>>
>> --
>> Guillaume Quintard
>>
>>
>> On Thu, Dec 26, 2019 at 3:12 PM Maninder Singh <mandys at gmail.com> wrote:
>>>
>>> Another one.
>>> This one is diff error.
>>>
>>> *   << BeReq    >> 19327398
>>> -   Begin          bereq 19327397 pass
>>> -   Timestamp      Start: 1577370022.344818 0.000000 0.000000
>>> -   BereqMethod    POST
>>> -   BereqURL       /LetsCelebrate
>>> -   BereqProtocol  HTTP/1.1
>>> -   BereqHeader    User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36
>>> -   BereqHeader    Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
>>> -   BereqHeader    Cache-Control: max-age=0
>>> -   BereqHeader    SSLClientCertStatus: NoClientCert
>>> -   BereqHeader    X-Forwarded-Proto: https
>>> -   BereqHeader    Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryBBVOJciq1v4rbZs9
>>> -   BereqHeader    Accept-Language: en-GB,en-US;q=0.9,en;q=0.8
>>> -   BereqHeader    SSLClientCipher: SSL_ECDHE_RSA_WITH_AES_256_GCM_SHA384, version=TLSv1.2, bits=256
>>> -   BereqHeader    Host: mydomain.com
>>> -   BereqHeader    Referer: https://mydomain.com/LetsCelebrate
>>> -   BereqHeader    SSLSessionID: 97258494A3DD008A855B552F701E9F95C25CDC7B1CF5FD63D382ED09391585C7
>>> -   BereqHeader    Origin: https://mydomain.com
>>> -   BereqHeader    X-Cluster-Client-Ip: X.X.X.X
>>> -   BereqHeader    X-Forwarded-Port: 443
>>> -   BereqHeader    Upgrade-Insecure-Requests: 1
>>> -   BereqHeader    Sec-Fetch-User: ?1
>>> -   BereqHeader    Sec-Fetch-Site: same-origin
>>> -   BereqHeader    Sec-Fetch-Mode: nested-navigate
>>> -   BereqHeader    Accept-Encoding: gzip, deflate, br
>>> -   BereqHeader    Content-Length: 2076
>>> -   BereqHeader    X-Forwarded-For: X.X.X.X, 10.187.187.36
>>> -   BereqHeader    browser: other
>>> -   BereqHeader    serverIp: 10.208.225.235
>>> -   BereqHeader    X-Varnish: 19327398
>>> -   VCL_call       BACKEND_FETCH
>>> -   VCL_return     fetch
>>> -   BackendOpen    23 reload_2019-12-18T054238.default 127.0.0.1 8080 127.0.0.1 39568
>>> -   BackendStart   127.0.0.1 8080
>>> -   FetchError     req.body read error: 11 (Resource temporarily unavailable)
>>> -   FetchError     backend write error: 11 (Resource temporarily unavailable)
>>> -   Timestamp      Bereq: 1577370027.344908 5.000090 5.000090
>>> -   BackendClose   23 reload_2019-12-18T054238.default
>>> -   Timestamp      Beresp: 1577370027.345014 5.000196 0.000105
>>> -   Timestamp      Error: 1577370027.345025 5.000206 0.000011
>>> -   BerespProtocol HTTP/1.1
>>> -   BerespStatus   503
>>> -   BerespReason   Service Unavailable
>>> -   BerespReason   Backend fetch failed
>>> -   BerespHeader   Date: Thu, 26 Dec 2019 14:20:27 GMT
>>> -   BerespHeader   Server: Varnish
>>> -   VCL_call       BACKEND_ERROR
>>> -   BerespHeader   Content-Type: text/html; charset=utf-8
>>> -   BerespHeader   Retry-After: 5
>>> -   VCL_return     deliver
>>> -   Storage        malloc Transient
>>> -   ObjProtocol    HTTP/1.1
>>> -   ObjStatus      503
>>> -   ObjReason      Backend fetch failed
>>> -   ObjHeader      Date: Thu, 26 Dec 2019 14:20:27 GMT
>>> -   ObjHeader      Server: Varnish
>>> -   ObjHeader      Content-Type: text/html; charset=utf-8
>>> -   ObjHeader      Retry-After: 5
>>> -   Length         1288
>>> -   BereqAcct      1276 0 1276 0 0 0
>>> -   End
>>>
>>> On Thu, 26 Dec 2019 at 17:27, Maninder Singh <mandys at gmail.com> wrote:
>>>>
>>>> Got one in the log.
>>>>
>>>> varnishlog -r /var/log/varnish/503.log
>>>> *   << BeReq    >> 21993384
>>>> -   Begin          bereq 21993383 pass
>>>> -   Timestamp      Start: 1577360704.829258 0.000000 0.000000
>>>> -   BereqMethod    POST
>>>> -   BereqURL       /corp/contact.php?cf=exitpopup
>>>> -   BereqProtocol  HTTP/1.1
>>>> -   BereqHeader    User-Agent: Mozilla/5.0 (Windows NT 6.1; Trident/7.0; rv:11.0) like Gecko
>>>> -   BereqHeader    Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/x-shockwave-flash, */*
>>>> -   BereqHeader    SSLClientCertStatus: NoClientCert
>>>> -   BereqHeader    X-Forwarded-Proto: https
>>>> -   BereqHeader    Content-Type: application/x-www-form-urlencoded
>>>> -   BereqHeader    SSLClientCipher: SSL_ECDHE_RSA_WITH_AES_256_CBC_SHA, version=TLSv1, bits=256
>>>> -   BereqHeader    Host: www.mydomain.com
>>>> -   BereqHeader    Referer: http://mydomain.com/solutions/enterprise.php
>>>> -   BereqHeader    SSLSessionID: 3C119EF3FE70318789F82E9B583581C876B4DDE520C0182C33CD6AF1AA46E63A
>>>> -   BereqHeader    X-Cluster-Client-Ip: X.X.X.X
>>>> -   BereqHeader    Cookie: X-Mapping-fjhppofk=E8F494E9A630955F1975EEDF11EBC4D7
>>>> -   BereqHeader    X-Forwarded-Port: 443
>>>> -   BereqHeader    Accept-Encoding: gzip, deflate
>>>> -   BereqHeader    Content-Length: 1366
>>>> -   BereqHeader    X-Forwarded-For: X.X.X.X, 10.187.187.36
>>>> -   BereqHeader    browser: other
>>>> -   BereqHeader    serverIp: 10.208.224.192
>>>> -   BereqHeader    X-Varnish: 21993384
>>>> -   VCL_call       BACKEND_FETCH
>>>> -   VCL_return     fetch
>>>> -   BackendOpen    26 reload_2019-12-18T054253.default 127.0.0.1 8080 127.0.0.1 59998
>>>> -   BackendStart   127.0.0.1 8080
>>>> -   Timestamp      Bereq: 1577360705.664932 0.835674 0.835674
>>>> -   FetchError     http first read error: EOF
>>>> -   BackendClose   26 reload_2019-12-18T054253.default
>>>> -   Timestamp      Beresp: 1577360705.665020 0.835763 0.000089
>>>> -   Timestamp      Error: 1577360705.665028 0.835770 0.000008
>>>> -   BerespProtocol HTTP/1.1
>>>> -   BerespStatus   503
>>>> -   BerespReason   Service Unavailable
>>>> -   BerespReason   Backend fetch failed
>>>> -   BerespHeader   Date: Thu, 26 Dec 2019 11:45:05 GMT
>>>> -   BerespHeader   Server: Varnish
>>>> -   VCL_call       BACKEND_ERROR
>>>> -   BerespHeader   Content-Type: text/html; charset=utf-8
>>>> -   BerespHeader   Retry-After: 5
>>>> -   VCL_return     deliver
>>>> -   Storage        malloc Transient
>>>> -   ObjProtocol    HTTP/1.1
>>>> -   ObjStatus      503
>>>> -   ObjReason      Backend fetch failed
>>>> -   ObjHeader      Date: Thu, 26 Dec 2019 11:45:05 GMT
>>>> -   ObjHeader      Server: Varnish
>>>> -   ObjHeader      Content-Type: text/html; charset=utf-8
>>>> -   ObjHeader      Retry-After: 5
>>>> -   Length         1288
>>>> -   BereqAcct      849 1366 2215 0 0 0
>>>> -   End
>>>>
>>>> On Thu, 26 Dec 2019 at 15:21, Maninder Singh <mandys at gmail.com> wrote:
>>>>>
>>>>> Okay. Let me set it up and get back to you once i see something in that log. It happens only once/twice a day so could be a while before i get back.
>>>>>
>>>>> On Thu, 26 Dec, 2019, 3:10 pm Guillaume Quintard, <guillaume at varnish-software.com> wrote:
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> Most probably, varnishncsa isn't going to give you the full picture, so let's go for the exhaustive way:
>>>>>>
>>>>>> varnishlog -q "BerespStatus eq 503" -w /whatever/file
>>>>>>
>>>>>>
>>>>>> you can then read the logs with
>>>>>>
>>>>>> varnishlog -r /whatever/file
>>>>>>
>>>>>>
>>>>>> (more logging pointers here: https://docs.varnish-software.com/tutorials/vsl-query/)
>>>>>>
>>>>>> If you can get your hands on a failed transaction, we should be able to tell you what went wrong. Most probably, you hit a timeout of some sort. Or it could be that the backend was declared sick, if you have probes.
>>>>>>
>>>>>> --
>>>>>> Guillaume Quintard
>>>>>>
>>>>>>
>>>>>> On Thu, Dec 26, 2019 at 6:33 AM Maninder Singh <mandys at gmail.com> wrote:
>>>>>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>> I am facing a strange problem.
>>>>>>>
>>>>>>> I am running varnish 4.1.11 on port 80 which is behind a LB.
>>>>>>>
>>>>>>> Varnish then connects to apache 2.4 ( on port 8080 ) and also have php-fpm running.
>>>>>>>
>>>>>>> Now, everything works fine but once in a while I am seeing 503 response from varnish for a POST request. During this time there is no log in apache also ( neither access log nor error log ).
>>>>>>>
>>>>>>> Where does this request vanish ?
>>>>>>>
>>>>>>> How do I debug this issue ?
>>>>>>>
>>>>>>> Some more details:
>>>>>>>
>>>>>>> * I have varnishncsa turned on with following flags.
>>>>>>>
>>>>>>> ExecStart=/usr/bin/varnishncsa -q 'not (ReqURL ~ "\.(js|css|png|jpeg|jpg|ico|gif|swf|woff)" or ReqHeader:User-Agent ~ "HTTP-Monitor" or ReqHeader:User-Agent ~ "Monitoring/1.1")' -a -w /var/log/varnish/varnishncsa.log -D -f /etc/sysconfig/varnishncsa
>>>>>>>
>>>>>>> Here is the entry in varnish log during that time.
>>>>>>>
>>>>>>> X.X.X.X, LB.IP.0.0 - - [25/Dec/2019:00:26:40 -0600] 2629363 "POST http://mydomain.com/LetsCelebrate HTTP/1.1" 503 1288 "https://referringdomain.com/LetsCelebrate?hostingUrl=https%3A%2F%2Fxy.abc.com" "Mozilla/5.0 (Linux; Android 9; SM-A920F) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.93 Mobile Safari/537.36" "mydomain.com" miss
>>>>>>>
>>>>>>> In .vcl file I have following set.
>>>>>>>  .first_byte_timeout = 120s;
>>>>>>>
>>>>>>> Now, I am not logging varnish to apache requests ( which backend fetch ).
>>>>>>> As you can see above I am only logging client requests.
>>>>>>>
>>>>>>> Is their a way to log client requests like above but then also log backend fetch failures to another log file ?
>>>>>>> [ Running 2 instances of varnishncsa ? ]
>>>>>>>
>>>>>>> Any pointers ?
>>>>>>>
>>>>>>> Please let me know.
>>>>>>>
>>>>>>> Thanks.
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> varnish-misc mailing list
>>>>>>> varnish-misc at varnish-cache.org
>>>>>>> https://www.varnish-cache.org/lists/mailman/listinfo/varnish-misc
>
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