How to configure Jenkins to run on port 80

Question

I'm running Ubuntu 11.10 and have run sudo apt-get install jenkins to install Jenkins on this system.

I've seen some tutorials on how to setup a reverse proxy (Apache, Nginx, etc), however this is a VM dedicated for just jenkins and I'd like keep it as lean as possible while having jenkins running on port 80.

I've found the upstart config in /etc/init/jenkins.conf and modified the port to 80 env HTTP_PORT=80

When I start jenkins via service jenkins start, ps reveals that it runs for a few seconds then terminates.

Is this because jenkins is running as the jenkins user on a privileged port? If so, how do I fix this? Any other ideas a welcome.

Here is the upstart config:

description "jenkins: Jenkins Continuous Integration Server"
author "James Page <[e-mail]>"

start on (local-filesystems and net-device-up IFACE!=lo)
stop on runlevel [!2345]

env USER="jenkins"
env GROUP="jenkins"
env JENKINS_LOG="/var/log/jenkins"
env JENKINS_ROOT="/usr/share/jenkins"
env JENKINS_HOME="/var/lib/jenkins"
env JENKINS_RUN="/var/run/jenkins"
env HTTP_PORT=80
env AJP_PORT=-1
env JAVA_OPTS=""
env JAVA_HOME="/usr/lib/jvm/default-java"

limit nofile 8192 8192

pre-start script
    test -f $JENKINS_ROOT/jenkins.war || { stop ; exit 0; }
    $JENKINS_ROOT/bin/maintain-plugins.sh   
    mkdir $JENKINS_RUN > /dev/null 2>&1  || true
    chown -R $USER:$GROUP $JENKINS_RUN || true
end script

script
    JENKINS_ARGS="--webroot=$JENKINS_RUN/war --httpPort=$HTTP_PORT --ajp13Port=$AJP_PORT"
    exec daemon --name=jenkins --inherit --output=$JENKINS_LOG/jenkins.log --user=$USER \
        -- $JAVA_HOME/bin/java $JAVA_OPTS -jar $JENKINS_ROOT/jenkins.war $JENKINS_ARGS \
        --preferredClassLoader=java.net.URLClassLoader
end script

Answer 1

Another solution is to simply use iptables to reroute incoming traffic from 80 to 8080. The rules would look like:

-A INPUT -i eth0 -p tcp --dport 80 -j ACCEPT
-A INPUT -i eth0 -p tcp --dport 8080 -j ACCEPT
-A PREROUTING -t nat -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 8080

Reformatted as an iptables.rules file:

*filter
:INPUT ACCEPT [100:100000]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [95:9000]
-A INPUT -i eth0 -p tcp --dport 80 -j ACCEPT
-A INPUT -i eth0 -p tcp --dport 8080 -j ACCEPT
COMMIT

*nat
-A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 8080
COMMIT

The advantage of a iptable.rules file is the rules can persist after reboots. Just make sure to integrate any other current iptable rules into the same file!

On Redhat/CentOS this file can go in /etc/sysconfig/iptables.

On Debian/Ubuntu systems they can be saved in /etc/iptables/rules.v4 by using the iptables-persistent package. Or the iptable.rules can be called by modifying /etc/network/interfaces or hooking into if-up/if-down scripts. The Ubuntu Community wiki has a great page explaining these methods.

As is usually the case with networking, there's a lot of different ways to accomplish the same result. Use what works best for you!

Answer 2

I had the same problem and I found the best solution to it using iptables.

By default Jenkins runs on ports 8080 or 8443. And HTTP/HTTPS servers run on ports 80 and 443.

But this is these are the special ports and the process using them must be owned by root.

But running Jenkins as root is not the best solution(it should be run as its own user) and so does to run Jenkins with a web server such as Apache, and let it proxy requests to Jenkins

The best solution is to use iptables on Linux to forward traffic.

1) Use this command to list the current iptables configuration:

$ iptables -L -n

target     prot opt source               destination
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:8443
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:8080
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:443
ACCEPT     tcp  --  0.0.0.0/0            0.0.0.0/0            tcp dpt:80

2) If you don't see above entries, then you need to run below commands:

sudo iptables -I INPUT 1 -p tcp --dport 8443 -j ACCEPT

sudo iptables -I INPUT 1 -p tcp --dport 8080 -j ACCEPT

sudo iptables -I INPUT 1 -p tcp --dport 443 -j ACCEPT

sudo iptables -I INPUT 1 -p tcp --dport 80 -j ACCEPT

3) Now re-run the $ iptables -L -n command and verify that you are seeing 1st step o/p.

4) The final step is to run the below commands to forward port 80 traffic to 8080, and port 443 traffic to 8443(if you are using HTTPS).

sudo iptables -A PREROUTING -t nat -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 8080

sudo iptables -A PREROUTING -t nat -i eth0 -p tcp --dport 443 -j REDIRECT --to-port 8443

5) Now your URL should stay on port 80

You can find the more details here.

Answer 3

Since I used docker. You can use it to run jenkins on port 80, hereafter a snippet of my script:

JENKINS_PORT=80
JENKINS_HOME=/home/jenkins
/usr/bin/docker run -d -p $JENKINS_PORT:8080 -v $JENKINS_HOME jenkins

Answer 4

In Ubuntu 16.04, this wiki explains how to do it.

sudo nano /etc/rc.local

Then add the following just before the exit 0

#Requests from outside
iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-ports 8080
#Requests from localhost
iptables -t nat -I OUTPUT -p tcp -d 127.0.0.1 --dport 80 -j REDIRECT --to-ports 8080

Now reboot or run sudo /etc/rc.local to enable port forwarding

Answer 5

changing /etc/default/jenkins doesn't work on my setup ubunutu 16.-4 Jenkins 2.89.4 and the solution to use iptable routes 80 to 8080 whis the opposite of the required result of running jenkins on 80

Answer 6

the firewalld way to forward port 8080 to 80:

yum install firewalld
systemctl start firewalld
chkconfig firewalld on
firewall-cmd --permanent --zone=external --change-interface=eth0
firewall-cmd --permanent --zone=external --add-forward-port=port=80:proto=tcp:toport=8080