id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
1022	"Nginx graceful shutdown doesn't inform clients to close ""keep-alive"" connections"	micheleorsi@…		"In case a client uses the keep-alive feature to make requests, during graceful shutdown it will receive some errors because it continues to re-use such connections. On the other hand when nginx is stopped those connections are not anymore valid and the clients will receive several errors.

I would expect that during graceful shutdown nginx inform the clients to close connection with specific HTTP header (Connection: close), so that the client can open brand new connections.

I suffer from this problem when I am in a configuration with F5 in front of several nginx. When I want to stop some of them and launch other instances, F5 stop sending new requests to the quitting nginx but clients with ""keep-alive"" connections continue to make requests against such instances. So that when nginx instances are stopped clients will receive drop connection errors because they were not informed about closing TCP connection on quitting nginx instances.

Here is a simple test to verify the behaviour:
- a simple service that serves traffic at http://localhost:8081/load
- nginx (1.10.1) runs in this way:
nginx -c sample.conf
- sample.conf is this:
events {}
http {
    server {
    listen 9999;

    location / {
      proxy_pass http://localhost:8081;
    }
  }
}

- ab testing running:
ab -v 2 -n 1000 -c 25 -k http://127.0.0.1:9999/load

When I launch ..

nginx -s quit

.. I continue to receive

Connection: keep-alive

.. until the very end, before nginx quit."	defect	closed	minor		other	1.10.x	wontfix	graceful, shutdown, keep-alive, tcp, connection		Darwin lm00281.local 15.4.0 Darwin Kernel Version 15.4.0: Fri Feb 26 22:08:05 PST 2016; root:xnu-3248.40.184~3/RELEASE_X86_64 x86_64	"nginx version: nginx/1.10.1
built by clang 7.3.0 (clang-703.0.31)
built with OpenSSL 1.0.2h  3 May 2016
TLS SNI support enabled
configure arguments: --prefix=/usr/local/Cellar/nginx/1.10.1 --with-http_ssl_module --with-pcre --with-ipv6 --sbin-path=/usr/local/Cellar/nginx/1.10.1/bin/nginx --with-cc-opt='-I/usr/local/Cellar/pcre/8.38/include -I/usr/local/Cellar/openssl/1.0.2h_1/include' --with-ld-opt='-L/usr/local/Cellar/pcre/8.38/lib -L/usr/local/Cellar/openssl/1.0.2h_1/lib' --conf-path=/usr/local/etc/nginx/nginx.conf --pid-path=/usr/local/var/run/nginx.pid --lock-path=/usr/local/var/run/nginx.lock --http-client-body-temp-path=/usr/local/var/run/nginx/client_body_temp --http-proxy-temp-path=/usr/local/var/run/nginx/proxy_temp --http-fastcgi-temp-path=/usr/local/var/run/nginx/fastcgi_temp --http-uwsgi-temp-path=/usr/local/var/run/nginx/uwsgi_temp --http-scgi-temp-path=/usr/local/var/run/nginx/scgi_temp --http-log-path=/usr/local/var/log/nginx/access.log --error-log-path=/usr/local/var/log/nginx/error.log --with-http_gzip_static_module
"