Question

Why can my application not use port 8080?

Posted on August 31, 2021
Ubuntu 20.04
Asked by simonprins

I am trying to run an application, but it doesn’t start, returning the following error: The Tomcat connector configured to listen on port 8080 failed to start. The port may already be in use or the connector may be misconfigured.

I tried using netstat to see what application is using port 8080, but it does not seem that there is any application listening on that port.

I tried changing the port to 8081 and 8082, but was unable to connect with those either.

Finally I used sudo to run the application and now it does start, however I do not want to run the application with root access.

Why can my application not use port 8080 without root access?

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simonprins • September 1, 2021

Accepted Answer

I have found the solution, it didn’t actually have anything to do with the port, the error message sent me looking in the wrong direction. My application didn’t have access to the keystore file where the ssl key was stored, so I needed to change the permissions on that file. After that my app worked fine.

This answer gave me the right clue, 6th answer on a relevant stackoverflow post. :') https://stackoverflow.com/a/56584497/10088785

KFSys

Site Moderator

• September 1, 2021

hi @simonprins,

You need root to start a service. It’s how it works.

If you do wish to start the systemd service without root though, you can use the sudoers file. In the sudoers files you can do something like :

Note: for the example the user and group is called DOquestion Put code in a custom file here: /etc/sudoers.d/DOquestion Code:

%DOquestionALL= NOPASSWD: /bin/systemctl start my_app
%DOquestionALL= NOPASSWD: /bin/systemctl stop my_app
%DOquestionALL= NOPASSWD: /bin/systemctl restart my_app

The above should do the trick.