From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <e@80x24.org>
X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on dcvr.yhbt.net
X-Spam-Level: 
X-Spam-ASN: 
X-Spam-Status: No, score=-2.9 required=3.0 tests=ALL_TRUSTED,AWL,BAYES_00,
 URIBL_BLOCKED shortcircuit=no autolearn=unavailable version=3.3.2
X-Original-To: unicorn-public@bogomips.org
Received: from localhost (dcvr.yhbt.net [127.0.0.1]) by dcvr.yhbt.net
 (Postfix) with ESMTP id 916191F6A8; Tue, 24 Mar 2015 22:54:38 +0000 (UTC)
Date: Tue, 24 Mar 2015 22:54:38 +0000
From: Eric Wong <e@80x24.org>
To: Michael Fischer <mfischer@zendesk.com>
Cc: unicorn-public <unicorn-public@bogomips.org>
Subject: Re: nginx reverse proxy getting ECONNRESET
Message-ID: <20150324225437.GA21975@dcvr.yhbt.net>
References:
 <CABHxtY7Sn5yaiR5a3gDk1G4XySE+UtfuqUTcOSdmwneXLD5rcg@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To:
 <CABHxtY7Sn5yaiR5a3gDk1G4XySE+UtfuqUTcOSdmwneXLD5rcg@mail.gmail.com>
List-Id: <unicorn-public@bogomips.org>

Michael Fischer <mfischer@zendesk.com> wrote:
> We have an nginx 1.6.2 proxy in front of a Unicorn 4.8.3 server that
> is frequently reporting the following error:
> 
> 2015/03/24 01:46:01 [error] 11217#0: *872231 readv() failed (104:
> Connection reset by peer) while reading upstream
> 
> The interesting things are:
> 
> 1) The upstream is a Unix domain socket (to which Unicorn is bound)
> 2) Unicorn isn't reporting that a child died in the error log (and I
> verified their lifetimes with ps(1))
> 
> Any hints as to what we should look for?

What changed recently with your setup?

Which OS/kernel version + vendor version?

Since you've been around a while, I take it this is only a recent issue?

Can you setup a test instance on a different nginx port/unicorn socket
and with a config.ru such as:

------------------------- 8< ----------------------
run(lambda do |env|
  $stderr.write("#$$ starting at #{Time.now}\n")
  # be sure to configure your unicorn timeout
  sleep
  # should not return, wait for unicorn to kill
end)
----------------------------------------------------

And hitting nginx with a single test request to reproduce the issue.

And see if it happens on the same/different hosts where you notice the
problem.