Nginx: when was configuration last reloaded?

Question

We use Nginx across multiple servers and are currently running 1.11.10.

I am creating an Ansible script to deploy some configuration changes. The script copies the new configuration file to the server and then issues a command to reload the Nginx configuration.

Is there any way I can confirm that the file has been reloaded successfully? Using "systemctl status nginx" at the command line just gives me the status of the server and details when it was last restarted, not when the configuration was last reloaded.

Many thanks in advance for any information or help.

Answer 1

That nginx -s reload return success(echo $?) tell us nginx load configurations successfully, but now the latest configuration may not worker for every request, because there maybe some connections with old worker are still not finished, at this time, the system has double worker processes as configured.

1. master-worker mode

   The master process load the new configurations and spawn new worker processes with it, then stop the the old worker process after they finish the already existed connections

   let's try with worker_processes 2;

   ✗ ./sbin/nginx
   ✗ ps aux|grep nginx
   larryhe         2572   Ss    2:43PM   0:00.00 nginx: master process ./sbin/nginx
   larryhe         2575   S     2:43PM   0:00.00 nginx: worker process
   larryhe         2573   S     2:43PM   0:00.00 nginx: worker process
   
   ✗ ./sbin/nginx -s reload
   ✗ ps aux|grep nginx
   larryhe         2572     Ss    2:43PM   0:00.01 nginx: master process ./sbin/nginx
   larryhe         2706     S     2:44PM   0:00.00 nginx: worker process
   larryhe         2705     S     2:44PM   0:00.00 nginx: worker process
   

   The second column is pid, we can see that pids of worker processes are different before and after reload.

2. single-master mode

   The master process apply the latest configuration within the process without restarting, it's done if nginx -s reload returns success.