Ubuntu server has a nice installation up-front that allows you to pre-select some tools and services at install you might want to have running on your new server.
If you happen to select Wekan it will default to port 8080.
If you then happen to want to install Jenkins via their Debian/Ubuntu method it will fail to fully install at the `sudo apt-get install jenkins` section due to the port 8080 already being occupied.
After running the above command you can edit port in the following file:
sudo nano /etc/default/jenkins
Edit the numbers of the identified port to something other than “8080”
# port for HTTP connector (default 8080; disable with -1)
You can see a video here: https://youtu.be/XVei-AeXLLo