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 <[email protected]>"

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

Solution 1

Give a try to 'authbind':

sudo apt-get install authbind
sudo touch /etc/authbind/byport/80
sudo chmod 500 /etc/authbind/byport/80 
sudo chown jenkins /etc/authbind/byport/80

Then modify the script above to have (add authbind before the $JAVA_HOME/bin/java part):

exec daemon --name=jenkins --inherit --output=$JENKINS_LOG/jenkins.log \
--user=$USER -- authbind $JAVA_HOME/bin/java $JAVA_OPTS \
-jar $JENKINS_ROOT/jenkins.war $JENKINS_ARGS \
--preferredClassLoader=java.net.URLClassLoader

For newer Jenkins installations (1.598) on newer Ubuntu installations (14.04) edit /etc/init.d/jenkins and add authbind before $JAVA

$SU -l $JENKINS_USER --shell=/bin/bash -c "$DAEMON $DAEMON_ARGS -- authbind $JAVA $JAVA_ARGS -jar $JENKINS_WAR $JENKINS_ARGS" || return 2

As mentioned by Alan (see comment below) if you need IPv6 and your system is lower than Quantal you can instead of using apt-get to install authbind download a higher version. Make sure you have libc6 and libc6-udeb installed. Here is authbind version 2.1.1 from Ubuntu:

• amd64
• i386

Then execute:

sudo dpkg -i authbind_2.1.1_amd64.deb
# or sudo dpkg -i authbind_2.1.1_i386.deb

sudo touch /etc/authbind/byport/80
sudo chmod 500 /etc/authbind/byport/80 
sudo chown jenkins /etc/authbind/byport/80

Solution 2

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!

Solution 3

1. Go to /etc/default folder --> Open the file "jenkins"
2. Modify the line HTTP_PORT=8080 as HTTP_PORT=80
3. Start jenkins as root by using the command: sudo /etc/init.d/jenkins start
4. Open a browser and browse as localhost:80

that's it

Solution 4

I'd suggest using apache and mod_proxy. This is what I do, and my vhost config looks kinda like this (I also redirect for SSL but you can omit that):

<VirtualHost *:443>
ServerAdmin [email protected]
ServerName ci.example.com

ProxyRequests Off
<Proxy *>
    Order deny,allow
    Allow from all
</Proxy>
ProxyPreservehost on
ProxyPass / http://localhost:8080/

Header edit Location ^http://ci.example.com/ https://ci.example.com/

SSLEngine on
SSLCertificateFile /etc/apache2/keys/apache.pem
</VirtualHost>

Solution 5

You can achieve this using the following methods.

1. An IP table forwarding rule.
2. Using a reverse proxy like Nginx.
3. Running Jenkins behind a load balancer.

Method 1: Running Jenkins On 80 Using IP Table Forwarding Rule

sudo iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-ports 8080

Now, you should save these rules so that it will persist even after an IPtable or a system restart.

For Redhat based systems, run the following.

sudo iptables-save > /etc/sysconfig/iptables

For Debian based systems, execute the following command.

sudo sh -c "iptables-save > /etc/iptables.rules"

Now if you access Jenkins on port 80, IP table will automatically forward the requests to 8080.

Method 2: Running Jenkins Behind Nginx Reverse Proxy

Step1: Install Nginx

sudo yum install nginx

Step 2: Open the Nginx configuration file.

sudo vi /etc/nginx/nginx.conf

Step 3: Find the following snippet in the nginx.conf file.

location / {
}

Step 4: Add the following lines between the curly braces.

proxy_pass http://127.0.0.1:8080;
proxy_redirect off;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;

Step 5: Execute the SELinux command for the Nginx reverse proxy.

sudo setsebool httpd_can_network_connect 1 -P

Step 6: Restart the Nginx server.

sudo systemctl restart nginx

Now if you will be able to access Jenkins on port 80.

Method 3: Jenkins Behind A Load Balancer

Adding a load balancer will add extra cost to the Jenkins setup. If you are on a cloud, you can opt for a cloud-specific load balancer which will send all its port 80 traffic to backend Jenkins 8080 port.

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