How to Reload or Restart Nginx without Interrupting Active Connections

During the operation of a web server powered by Nginx, it is sometimes necessary to reload or restart the server to apply configuration changes or update the software. However, simply restarting the server can lead to interrupted connections and downtime for your website users. Thankfully, there are alternative methods provided by Nginx to perform these actions without interrupting active connections.

1. Reloading Nginx Configuration

To reload the Nginx configuration without interrupting active connections, follow these steps:

1. Connect to your server via SSH or open the terminal.
2. Type the following command to check the syntax of the configuration file:

   sudo nginx -t

3. If the syntax is correct, you will see a success message. Now, reload the configuration by executing the following command:

sudo systemctl reload nginx

4. Nginx will reload the configuration file without ending active connections, preserving the uptime of your website.

2. Graceful Restart

If you need to update the Nginx software itself (for example, after an upgrade), you can perform a graceful restart which ensures minimal downtime:

1. Connect to your server via SSH or open the terminal.
2. Type the following command to check the syntax of the configuration file:

sudo nginx -t

3. If the syntax is correct, you will see a success message. Proceed with the graceful restart:

sudo systemctl upgrade nginx

4. During the graceful restart, Nginx will start new worker processes with the updated software, while the old worker processes continue handling active connections. Once the new worker processes are ready, the old ones are gracefully closed, resulting in a seamless transition.

Conclusion

Being able to reload or restart Nginx without interrupting active connections is crucial for maintaining the availability and stability of your website. By following the steps outlined in this article, you can ensure a smooth process when making configuration changes or updating Nginx, minimizing downtime and providing a seamless experience for your users.