By default, the installation wizard does not allow to run Jira on port 80. You can, however add a proxy to listen on port 80 and reroute the traffic to 8080. To do this we'll use Apache, but before that let's stop the Jira service.
sudo service jira stop
If set up correctly, you should see the following:
Next, install Apache and enable the proxy module:
sudo apt-get install apache2
sudo service apache2 stop
Once Apache is installed and proxy module enabled, we need to create a configuration file which will pass our request to Jira daemon.
sudo vi /etc/apache2/sites-available/jira.conf
Your configuration file should be similar to this:
ProxyPass / http://localhost:8080/
ProxyPassReverse / http://localhost:8080/
Now, navigate to /opt/atlassian/jira/conf/ and append the following line to the end of catalina connector found in server.xml
Once complete, start jira and reload apache.
sudo service jira start
sudo service apache2 reload
Give it few minutes since Jira is a multithreading application and less powerful computers will take a while to boot up. Once it's online, you can access it through your domain.