varnish-misc Digest, Vol 97, Issue 16

L Cruzero lcruzero at gmail.com
Thu Apr 17 13:51:48 CEST 2014


Geoff, Et al, thanks for your replies, i should have mentioned, that the
503's are not unique to POST requests, they are also happening more
frequent within
(very rarely == on 0.0038% of requests), on a GETs. i've been thinking of
testing within my config something along this FOUND vcl code snipped as a
possible solution.



*sub vcl_fetch {
**           if (obj.status == 500 || obj.status == 503 || obj.status ==
**        504) {
**                   restart;
**            }*



174 ReqStart     c 10.33.13.254 38233 1505576793
  174 RxRequest    c GET
  174 RxURL        c /auburnfootball/modules/most_read.html
  174 RxProtocol   c HTTP/1.1
  174 RxHeader     c If-Modified-Since: Wed, 16 Apr 2014 14:23:34 GMT
  174 RxHeader     c Accept:
text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
  174 RxHeader     c Accept-Charset: utf-8, iso-8859-1, utf-16, *;q=0.7
  174 RxHeader     c Accept-Language: en-US
  174 RxHeader     c Cookie: adv_lid=04ea3e9b86834130c4cb3be359f7b220;
OAX=RsRvNFEDhgkAAuO2; __qca=P0-1959933173-1359185426964;
__atuvc=0%7C27%2C0%7C28%2C0%7C29%2C0%7C30%2C1%7C31;
mp_948b359d7741fa246376d95399585cc3_mixpanel=%7B%7D;
__utma=130511327.2000905843.1375913741.1375
  174 RxHeader     c User-Agent: Mozilla/5.0 (Linux; U; Android 4.1.2;
en-us; SCH-I200 Build/JZO54K) AppleWebKit/534.30 (KHTML, like Gecko)
Version/4.0 Mobile Safari/534.30
  174 RxHeader     c X-UIDH:
MTQ5ODI0NDA2MAA/58mlyaG6h8c9ATsT9BtivrzyjC/Gl0mdhNCPRIOC1Q==
  174 RxHeader     c x-wap-profile:
http://uaprof.vtext.com/sam/SCH-I200/SCH-I200.xml
  174 RxHeader     c X-Akamai-Esi-Fragment-Suffix: f.6
  174 RxHeader     c True-Client-IP: 127.0.0.1
  174 RxHeader     c X-Akamai-CONFIG-LOG-DETAIL: true
  174 RxHeader     c TE:  chunked;q=1.0
  174 RxHeader     c Connection: TE
  174 RxHeader     c Akamai-Origin-Hop: 2
  174 RxHeader     c Via: 4.0 asi_server, 1.0 v1-akamaitech.net(ghost)
(AkamaiGHost), 1.1 akamai.net(ghost) (AkamaiGHost)
  174 RxHeader     c Accept-ESI: 1.0
  174 RxHeader     c X-Forwarded-For: 127.0.0.1, 96.17.202.197
  174 RxHeader     c Host: www.al.com
  174 RxHeader     c Cache-Control: max-age=180
  174 RxHeader     c Connection: keep-alive
  174 RxHeader     c X-Forwarded-For: 23.73.180.223
  174 RxHeader     c Accept-Encoding: identity
  174 VCL_call     c recv pass
  174 VCL_call     c hash
  174 Hash         c /auburnfootball/modules/most_read.html
  174 Hash         c www.**.com
  174 VCL_return   c hash
  174 VCL_call     c pass pass
  174 Backend      c 101 www_prod www_prod
  174 FetchError   c http first read error: -1 104 (Connection reset by
peer)
  174 Backend      c 56 www_prod www_prod
  174 FetchError   c http first read error: -1 104 (Connection reset by
peer)
  174 VCL_call     c error deliver
  174 VCL_call     c deliver deliver
  174 TxProtocol   c HTTP/1.1
  174 TxStatus     c 503
  174 TxResponse   c Service Unavailable
  174 TxHeader     c Server: Varnish
  174 TxHeader     c Content-Type: text/html; charset=utf-8
  174 TxHeader     c Retry-After: 5
  174 TxHeader     c Content-Length: 419
  174 TxHeader     c Accept-Ranges: bytes
  174 TxHeader     c Date: Wed, 16 Apr 2014 16:30:29 GMT
  174 TxHeader     c X-Varnish: 1505576793
  174 TxHeader     c Age: 0
  174 TxHeader     c Via: 1.1 varnish
  174 TxHeader     c Connection: close
  174 Length       c 419
  174 ReqEnd       c 1505576793 1397665829.285193920 1397665829.298522949
0.022354841 0.013305187 0.000023842


On Thu, Apr 17, 2014 at 6:00 AM, <varnish-misc-request at varnish-cache.org>wrote:

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> Today's Topics:
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>    1. Re: intermittent 503's (Geoffrey Simmons)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 17 Apr 2014 17:46:21 +1200
> From: Geoffrey Simmons <geoff at uplex.de>
> To: L Cruzero <lcruzero at gmail.com>
> Cc: "varnish-misc at varnish-cache.org" <varnish-misc at varnish-cache.org>
> Subject: Re: intermittent 503's
> Message-ID: <A1B813DE-4217-4546-9E65-E0D9139C684B at uplex.de>
> Content-Type: text/plain; charset="us-ascii"
>
> >    35 FetchError   c backend write error: 104 (Connection reset by peer)
>
> "backend write error" in versions up to at least 3.0.3 can be a very
> misleading error message -- you may in fact have had a connection reset on
> the *client* connection while reading the request body of your POST
> request. In my experience, that's much more common than an error writing to
> the backend connection.
>
> Sending the request body to the backend is part of the fetch operation,
> which is why an error in that phase is logged as a FetchError. Varnish
> reads the body from the client and writes it to the backend in a loop, so
> if any error occurs then, either on the client or backend side, it's logged
> as "FetchError: backend write error".
>
> There was a fix that made the error message distinguish the problem more
> clearly, might have made it into 3.0.4.
>
> Anyway if I were you I'd look for a connection reset on a read of the POST
> body from the client connection.
>
>
> HTH,
> Geoff
>
> Sent from my iPad
>
> > On Apr 17, 2014, at 12:37 AM, L Cruzero <lcruzero at gmail.com> wrote:
> >
> > Hi,  in our varnish setup(varnish-3.0.3-1.el5) using a loadbalanced
> really Healthy VIP as the only backend, we seem to be getting intermittent
> 503's
> >
> >
> > stdout captured with varnishlog -c -m TxStatus:503
> >
> >    35 ReqStart     c 10.33.13.254 24582 1166630723
> >    35 RxRequest    c POST
> >    35 RxURL        c
> /index.php?option=com_jce&task=plugin&plugin=imgmanager&file=imgmanager&method=form&cid=20&6bc427c8a7981f4fe1f5ac65c1246b5f=cf6dd3cf1923c950586d0dd595c8e20b
> >    35 RxProtocol   c HTTP/1.1
> >    35 RxHeader     c User-Agent: BOT/0.1 (BOT for JCE)
> >    35 RxHeader     c Content-Type: multipart/form-data;
> boundary=---------------------------41184676334
> >    35 RxHeader     c Content-Length: 5000
> >    35 RxHeader     c True-Client-IP: 202.80.119.178
> >    35 RxHeader     c X-Akamai-CONFIG-LOG-DETAIL: true
> >    35 RxHeader     c TE:  chunked;q=1.0
> >    35 RxHeader     c Connection: TE
> >    35 RxHeader     c Akamai-Origin-Hop: 2
> >    35 RxHeader     c Via: 1.1 v1-akamaitech.net(ghost) (AkamaiGHost),
> 1.1 akamai.net(ghost) (AkamaiGHost)
> >    35 RxHeader     c X-Forwarded-For: 202.80.119.178, 114.4.39.206
> >    35 RxHeader     c Host: www.somedomain.com
> >    35 RxHeader     c Cache-Control: max-age=120
> >    35 RxHeader     c Connection: keep-alive
> >    35 RxHeader     c X-Forwarded-For: 23.73.180.223
> >    35 RxHeader     c Accept-Encoding: identity
> >    35 VCL_call     c recv pass
> >    35 VCL_call     c hash
> >    35 Hash         c
> /index.php?option=com_jce&task=plugin&plugin=imgmanager&file=imgmanager&method=form&cid=20&6bc427c8a7981f4fe1f5ac65c1246b5f=cf6dd3cf1923c950586d0dd595c8e20b
> >    35 Hash         c www.somedomain.com
> >    35 VCL_return   c hash
> >    35 VCL_call     c pass pass
> >    35 Backend      c 29 www_prod www_prod
> >    35 FetchError   c backend write error: 104 (Connection reset by peer)
> >    35 Backend      c 42 www_prod www_prod
> >    35 FetchError   c backend write error: 104 (Connection reset by peer)
> >    35 VCL_call     c error deliver
> >    35 VCL_call     c deliver deliver
> >    35 TxProtocol   c HTTP/1.1
> >    35 TxStatus     c 503
> >    35 TxResponse   c Service Unavailable
> >    35 TxHeader     c Server: Varnish
> >    35 TxHeader     c Content-Type: text/html; charset=utf-8
> >    35 TxHeader     c Retry-After: 5
> >    35 TxHeader     c Content-Length: 419
> >    35 TxHeader     c Accept-Ranges: bytes
> >    35 TxHeader     c Date: Tue, 15 Apr 2014 19:31:22 GMT
> >    35 TxHeader     c X-Varnish: 1166630723
> >    35 TxHeader     c Age: 0
> >    35 TxHeader     c Via: 1.1 varnish
> >    35 TxHeader     c Connection: close
> >    35 Length       c 419
> >    35 ReqEnd       c 1166630723 1397590282.467632055
> 1397590282.899372101 0.033779144 0.431685925 0.0000541
> >
> >
> > here is super simple pass thru NO cache config :
> >
> >
> > backend www_prod {
> >   .host = "cs-****.*****.*****.net";
> >   .port = "80";
> >   .probe = {
> >         .url = "/";
> >         .timeout = 5s;
> >         .interval = 1s;
> >         .window = 5;
> >         .threshold = 2;
> >   }
> > }
> >
> >  sub vcl_recv {
> >       if (req.http.X-ADI-MISS) {
> >         # Force a cache miss
> >                  set req.hash_always_miss = true;
> >         }
> >
> >         if (req.url == "/varnish-health/" || req.url ~ "^/stack-check*")
> {
> >                 error 200 "Varnish is responding";
> >                 set req.http.Connection = "close";
> >   }
> >
> >
> >     if (req.http.host ~ "^(origin|www)") {
> >         set req.http.host = regsub(req.http.host, "^origin\.", "www.");
> >         set req.backend = www_prod;
> >         return(pass);
> >
> > }
> >
> >
> > ## we tried with and w/o these conditions intermittent 503's persisted
> >
> > #       if (req.backend.healthy) {
> > #       set req.grace = 30s;
> > #   } else {
> > #       set req.grace = 24h;
> > #   }
> >
> >  }
> >
> >
> > sub vcl_fetch {
> > #            set beresp.do_esi = true;
> >             set beresp.ttl = 1m;
> >
> > #           set beresp.grace = 24h;
> > }
> >
> >
> > Any helpful thoughts and or possible leads on this will be much
> appreciated.
> > kind regards,
> > -LC
> >
> > _______________________________________________
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