id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
2160	Cache loader process doesn't exit after master process is stopped with SIGQUIT.	ray.ward.bigcommerce.com@…		"When gracefully shutting down nginx with SIGQUIT, if the cache loader process is still running (we have large caches of lots of small files) then it will hold up nginx from quitting. It seems like the master process isn't passing this signal onto the cache loader. 

After SIGQUIT to nginx, workers are in process of shutting down:

{{{
# ps aux | grep nginx | grep -vE ""(grep|mtail)""
root     18737  0.0  0.0 2660400 16544 ?       Ss   23:32   0:00 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;
www-data 19174 55.8  0.6 2746968 223120 ?      S<   23:33   1:46 nginx: worker process is shutting down
www-data 19178 17.2  0.4 2692984 134156 ?      S<   23:33   0:32 nginx: worker process is shutting down
www-data 19180  5.8  0.2 2674952 87192 ?       S<   23:33   0:11 nginx: worker process is shutting down
www-data 19187 16.6  0.4 2658824 163728 ?      R    23:33   0:31 nginx: cache loader process
root     22216  0.0  0.0  32828  3736 pts/1    S+   23:35   0:00 systemctl stop nginx.service
root     22220  0.1  0.0   2304   820 ?        Ss   23:35   0:00 /sbin/start-stop-daemon --quiet --stop --retry QUIT/300/TERM/5/KILL/5 --pidfile /run/nginx.pid
}}}

After all the workers have stopped, nginx is lingering due to the cache loader still running:

{{{
# ps aux | grep nginx | grep -vE ""(grep|mtail)""
root     18737  0.0  0.0 2660400 16544 ?       Ss   23:32   0:00 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;
www-data 19187 19.2  1.0 2658824 343776 ?      S    23:33   0:56 nginx: cache loader process
root     22216  0.0  0.0  32828  3736 pts/1    S+   23:35   0:00 systemctl stop nginx.service
root     22220  0.1  0.0   2304   820 ?        Ss   23:35   0:00 /sbin/start-stop-daemon --quiet --stop --retry QUIT/300/TERM/5/KILL/5 --pidfile /run/nginx.pid
}}}

Sending SIGQUIT directly to the cache loader will stop it and allow nginx to finish up:

{{{
# kill -s SIGQUIT 19187
# ps aux | grep nginx | grep -vE ""(grep|mtail)""
}}}

"	defect	closed	minor		documentation	1.15.x	worksforme			Linux store-lb-129k 4.19.0-14-cloud-amd64 #1 SMP Debian 4.19.171-2 (2021-01-30) x86_64 GNU/Linux	"nginx version: openresty/1.15.8.2
built by gcc 8.3.0 (Debian 8.3.0-6)
built with OpenSSL 1.1.1d  10 Sep 2019
TLS SNI support enabled
configure arguments: --prefix=/usr/share/nginx/nginx --with-debug --with-cc-opt='-DNGX_LUA_USE_ASSERT -DNGX_LUA_ABORT_AT_PANIC -O2 -I/usr/include/ossp' --add-module=../ngx_devel_kit-0.3.1rc1 --add-module=../echo-nginx-module-0.61 --add-module=../xss-nginx-module-0.06 --add-module=../ngx_coolkit-0.2 --add-module=../set-misc-nginx-module-0.32 --add-module=../form-input-nginx-module-0.12 --add-module=../encrypted-session-nginx-module-0.08 --add-module=../srcache-nginx-module-0.31 --add-module=../ngx_lua-0.10.15 --add-module=../ngx_lua_upstream-0.07 --add-module=../headers-more-nginx-module-0.33 --add-module=../array-var-nginx-module-0.05 --add-module=../memc-nginx-module-0.19 --add-module=../redis2-nginx-module-0.15 --add-module=../redis-nginx-module-0.3.7 --add-module=../rds-json-nginx-module-0.15 --add-module=../rds-csv-nginx-module-0.09 --add-module=../ngx_stream_lua-0.0.7 --with-ld-opt='-Wl,-rpath,/usr/share/nginx/luajit/lib -lossp-uuid' --sbin-path=/usr/sbin/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --pid-path=/var/run/nginx.pid --with-compat --with-pcre-jit --with-http_ssl_module --with-ipv6 --lock-path=/var/lock/nginx.lock --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-http_gzip_static_module --with-openssl=/build/openssl/openssl-1.1.1d --with-http_realip_module --with-http_ssl_module --with-http_realip_module --with-http_auth_request_module --with-http_gunzip_module --with-file-aio --with-threads --with-http_stub_status_module --with-http_geoip_module --with-http_gunzip_module --with-http_sub_module --with-http_v2_module --add-module=/build/modules/ngx_cache_purge-2.3 --add-module=/build/modules/nginx-module-vts-0.1.18 --with-stream --with-stream_ssl_module --with-stream_ssl_preread_module"