What is the difference between 'service apache2 reload' and 'sudo systemctl restart apache2'?
We could define it like this:
Restart--> STOP the service and then it will START the service.
Now comes Reload option.
Reload--> Read .service file for which you have executed the command and if any changes happened it will start using those changes now, so each time a change happens in any service file a reload is needed. You could even see this message coming, lets say you have changed a service and you forgot to reload it so whenever you run any systemctl command towards that service it will throw an error to reload it.