How to install jenkins in ubuntu

In this article i am going to explain you how to install and configure Jenkins on your ubuntu operating system. Jenkins is an application that monitors execution of repeated jobs such as building a software project, it can be java, C++ or any other projects, Jenkins is a continuous integration and continuous delivery system which is written in Java, which automatically build,test and deploy software projects, Jenkins focusing on building and testing software projects continuously ,   

In order to have Jenkins on a Ubuntu operating system you need to have java JDK on your ubuntu operating system, SO we will install java JDK                                                      

Java Installation :
#add-apt-repository ppa:webupd8team/java
#apt-get update
#apt-get install oracle-java8-installer

to check java version :

#javac --version

 Install Jenkins :

#wget -q -O - | sudo apt-key add -
#echo deb binary/ | sudo tee /etc/apt/sources.list.d/jenkins.list
#apt-get update
#apt-get install jenkins

Start Jenkins service :
#systemctl start jenkins
#systemctl status jenkins

Allow jenkins default port from firewall :
#ufw allow 8080
#ufw status

Open jenkins on your browser with your server host name or Ip.

Unlock jenkins from below file from ther server for the password.
#cat /var/lib/jenkins/secrets/initialAdminPassword

We can also use apache default port 80 for open jenkins. we will configure jenkins on port 80 with use of apache proxy. First we have to install apache2 on ubuntu machine and enable apache proxy also :

#apt-get install apache2
#a2enmod proxy
#a2enmod proxy_http

Now create a jenkins.conf file in /etc/apache2/sites-available
vim /etc/apache2/sites-available/jenkins.conf and put below lines.

<VirtualHost *:80>
ProxyRequests Off
<Proxy *>
Order deny,allow
Allow from all
ProxyPreserveHost on
ProxyPass / http://localhost:8080/

Now enable jenkins.conf file for apache.
#a2ensite jenkins
#service apache2 restart

Now you can access jenkins without giving any port, it will using default 80 apache port.

Install Jenkins On CentOs operating system : 

#yum install -y wget
#sudo wget -O /etc/yum.repos.d/jenkins.repo
#sudo rpm –import
#sudo yum install jenkins
#sudo yum install java-1.7.0-openjdk
#firewall-cmd –zone=public –add-port=8080/tcp –permanent
#firewall-cmd –reload
#sudo /etc/init.d/jenkins restart
#systemctl restart jenkins.service

Open http://localhost:8080 URL in browser