我有一个用于 Sinatra 应用程序的 systemd 服务，该服务在 Nginx 反向代理后面的 Thin 服务器上运行。它运行正常，但由于它接收大量流量，我看到很多有关无法连接到上游的 nginx 错误。在检查服务时，我发现它运行的时间从不长，最多只有几分钟，这可以解释为什么 Nginx 很多时候都无法连接（在服务重新启动时）。
查看该服务的输出，journalctl我看到很多这样的内容：
Dec 20 22:09:48 cs2092 systemd[1]: Started My app web site.
Dec 20 22:10:59 cs2092 bundle[11576]: pure virtual method called
Dec 20 22:10:59 cs2092 bundle[11576]: terminate called without an active exception
Dec 20 22:10:59 cs2092 systemd[1]: my-service.service: Main process exited, code=killed, status=6/ABRT
Dec 20 22:10:59 cs2092 systemd[1]: my-service.service: Failed with result 'signal'.
Dec 20 22:10:59 cs2092 systemd[1]: my-service.service: Service hold-off time over, scheduling restart.
Dec 20 22:10:59 cs2092 systemd[1]: my-service.service: Scheduled restart job, restart counter is at 7.
Dec 20 22:10:59 cs2092 systemd[1]: Stopped My app web site.
Dec 20 22:10:59 cs2092 systemd[1]: Started My app web site.
Dec 20 22:11:19 cs2092 bundle[11828]: pure virtual method called
Dec 20 22:11:19 cs2092 bundle[11828]: terminate called without an active exception
Dec 20 22:11:19 cs2092 systemd[1]: my-service.service: Main process exited, code=killed, status=6/ABRT
Dec 20 22:11:19 cs2092 systemd[1]: my-service.service: Failed with result 'signal'.
Dec 20 22:11:19 cs2092 systemd[1]: my-service.service: Service hold-off time over, scheduling restart.
Dec 20 22:11:19 cs2092 systemd[1]: my-service.service: Scheduled restart job, restart counter is at 8.
Dec 20 22:11:19 cs2092 systemd[1]: Stopped My app web site.
Dec 20 22:11:19 cs2092 systemd[1]: Started My app web site.
Dec 20 22:14:28 cs2092 bundle[11968]: pure virtual method called
Dec 20 22:14:28 cs2092 bundle[11968]: terminate called without an active exception
Dec 20 22:14:28 cs2092 systemd[1]: my-service.service: Main process exited, code=killed, status=6/ABRT
Dec 20 22:14:28 cs2092 systemd[1]: my-service.service: Failed with result 'signal'.
Dec 20 22:14:28 cs2092 systemd[1]: my-service.service: Service hold-off time over, scheduling restart.
Dec 20 22:14:28 cs2092 systemd[1]: my-service.service: Scheduled restart job, restart counter is at 9.
Dec 20 22:14:28 cs2092 systemd[1]: Stopped My app web site.
Dec 20 22:14:28 cs2092 systemd[1]: Started My app web site.
看起来应用程序经常被终止？为什么会发生这种情况？
服务如下：
[Unit]
Description=My app web site
Documentation=https://myapp.com
After=network.target
[Service]
Type=simple
WorkingDirectory=/var/www/my-app
Environment="RACK_ENV=production"
ExecStart=/usr/local/bin/bundle exec /usr/local/bin/thin -R /var/www/my-app/config.ru -p 6903 --max-conns 15360 --max-persistent-conns 2048 --threaded --debug start
ExecStop=/usr/local/bin/bundle exec /usr/local/bin/thin -R /var/www/my-app/config.ru -p 6903 stop
ExecReload=/usr/local/bin/bundle exec /usr/local/bin/thin -R /var/www/my-app/config.ru -p 6903 --max-conns 15360 --max-persistent-conns 2048 --threaded --debug restart
Restart=on-failure
User=julien
[Install]
WantedBy=multi-user.target
还有一件事我不明白，正如您从我启动 Sinatra 的服务中看到的那样--max-conns 15360，但在journalctl输出中我可以看到最大连接数设置为 1024：
Dec 21 10:24:24 cs2092 bundle[21058]: Starting my-app in production...
Dec 21 10:24:24 cs2092 bundle[21058]: 2021-12-21 10:22:30 +0000 Thin web server (v1.8.1 codename Infinite Smoothie)
Dec 21 10:24:24 cs2092 bundle[21058]: 2021-12-21 10:22:30 +0000 Debugging ON
Dec 21 10:24:24 cs2092 bundle[21058]: 2021-12-21 10:22:30 +0000 Maximum connections set to 1024
Dec 21 10:24:24 cs2092 bundle[21058]: 2021-12-21 10:22:30 +0000 Listening on 0.0.0.0:6903, CTRL+C to stop
知道发生什么事了吗？
注意：Ubuntu 18.04.4
答案1
所以看起来问题出在 Thin 服务器上，一旦我用 Puma 替换它，所有问题就消失了。