What is the difference between systemctl restart and systemctl reload?

systemctl restart completely stops and then starts the service again. This results in a full restart of the process, which may cause a temporary unavailability of the service.

systemctl reload sends a signal to the service to re-read its configuration without stopping the process. This is a softer way to update settings if the service supports such an operation.

Example:

• For nginx, systemctl reload nginx will re-read the configuration without interrupting operation.
• If the service does not support reload, then systemctl reload may not work, and you need to use restart.