99.999% my config works - then default_server is used

[Ruslan Ermilov]

On Thu, Apr 06, 2017 at 11:18:02PM +0200, Michal Kralik wrote:
> Hi,
> 
> We're facing super strange issues with nginx 1.10.3 (CentOS 7,
> 3.10.0-327.36.3.el7.x86_64). Our config works ok, we get a lot of traffic,
> but every day a couple of requests (5-10) don't get processes correctly by
> a server directive with the defined server_name, but rather by a server
> directive with listen's "default_server". Here's the config
> https://paste.ngx.cc/29345124359e0447
> 
> Most of the time a request to 01.app.example.com gets processed correctly,
> but every day a couple of requests get processed by the server directive
> from file conf.d/01-default.conf. There's nothing in the nginx system logs
> around the time when this issue happens.
> 
> The access.log from the default_server shows this
> (/data/logs/nginx/access.log):
> 1.1.1.1 - - [06/Apr/2017:12:20:57 +0000] "01.app.example.com" "GET
> /robots.txt HTTP/1.1" 302 161 "-" "Mozilla/5.0 (compatible; Googlebot/2.1; +
> http://www.google.com/bot.html)" "-"
> 
> It's clearly a redirect processed by the default_server, but the request
> should be rather processed by server directive in conf.d/02-apps.conf
> because the host header clearly states "01.app.example.com".
> 
> Any ideas what's going on?

Given the provided configuration snippet, this should happen
with all HTTPS requests to 01.app.example.com.