Default listener port 8080 can be changed by supplying JENKINS_OPTS with the "httpPort" variable in Dockerfile or docker run command.

With httpPort=80 the container no longer takes web connections. When any other value is passed, e.g. httpPort=8081, it works fine.

I am not interested in mapping the container ports to the host ports via Docker (e.g. "-p 80:8080"). I am talking about the container itself.

Since any web applications allow to change the port at which the application within the container will listen, and there is this explicit "httpPort" option that does not work in this specific case, I am suspecting a bug.

Note also that adding a "<httpPort>80</httpPort>" to the config in /var/jenkins_home/config.xml does not work either. That tag is simply ignored and removed from the config.xml when the Jenkins container comes up.

If not a bug then might I ask how this can be intended behavior.