Lucas Lima's questions

It seems that the system itself is stopping my reverse proxy with nginx, there is no error in the nginx logs or in the system logs, the information I have is just below:

root@production:~# service nginx status
● nginx.service - A high performance web server and a reverse proxy server
   Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
   Active: inactive (dead) since Wed 2021-02-10 08:22:09 -03; 2h 35min ago
     Docs: man:nginx(8)
  Process: 15642 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
  Process: 15643 ExecStart=/usr/sbin/nginx -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
  Process: 22295 ExecStop=/sbin/start-stop-daemon --quiet --stop --retry QUIT/5 --pidfile /run/nginx.pid (code=exited, status=0/SUCCESS)
 Main PID: 15644 (code=exited, status=0/SUCCESS)

fev 09 17:01:13 production systemd[1]: Starting A high performance web server and a reverse proxy server...
fev 09 17:01:13 production systemd[1]: Started A high performance web server and a reverse proxy server.
fev 10 08:22:09 production systemd[1]: Stopping A high performance web server and a reverse proxy server...
fev 10 08:22:09 production systemd[1]: nginx.service: Succeeded.
fev 10 08:22:09 production systemd[1]: Stopped A high performance web server and a reverse proxy server.

This is the log that appears in the syslog, whenever it stops the log is always the same, such a root user starts the session and nginx starts the shutdown.

Feb 10 08:22:09 production systemd[1]: Started Session 158 of user root.
Feb 10 08:22:09 production systemd[1]: Stopping A high performance web server and a reverse proxy server...
Feb 10 08:22:09 production systemd[1]: nginx.service: Succeeded.
Feb 10 08:22:09 production systemd[1]: Stopped A high performance web server and a reverse proxy server.
Feb 10 08:22:09 production systemd[1]: session-158.scope: Succeeded.

When I look at the last logins with the command last -10, I see that only I logged into the system and no one else, it is as if the operating system itself was stopping nginx, can someone help me?

I forgot to mention that nginx runs for a while, and then stops suddenly, for example, the last time, it ran for 21 hours and then stopped alone.

I had a Debian 9.3 server, with a nginx reverse proxy. I decided to migrate to Ubuntu 20.04, installed nginx, and HTTPS does not work at all on an old device that runs windows ce 6.1.

Out of curiosity I decided to install Debian again, and install nginx and configure the reverse proxy, and HTTPS returned to work on the old device. The version of nginx that I was having problems with on Ubuntu is 1.18, which is the same version that I installed on Debian.

The error that the old mobile device returns when accessing the application in Ubuntu is: undefined path or network problem.

How can I solve this problem?

Does the nginx reverse proxy on Ubuntu need any specific header or configuration?

When reading the article on the link below, I had some doubts, I will explain my scenario and talk about my doubt.

https://dzone.com/articles/upstream-php-fpm-for-better-performance-1

I currently have a 32 GB memory server, of which I left 20 GB for PHP-FPM. I have a www.conf file, and I am using the "ondemand" method, the average consumption of my PHP-FPM pools is 29 MB, so my pm.max_children is equal to 690, my pm.process_idle_timeout is 15s, and my pm.max_requests is equal to 1000.

Is it worth it to create another www2.conf, calculate 10 GB of memory for each one, and do the "load balance" of the requests that are entering using the upstream of nginx? Can this increase the performance and redundancy of my sites?