Jenkins is a free and open source CI (Continuous Integration) tool which is written in JAVA. Jenkins is widely used for project development, deployment, and automation. Jenkins allows you to automate the non-human part of the whole software development process. It supports version control tools, including AccuRev, CVS, Subversion, Git, Mercurial, Perforce, ClearCase and RTC, and can execute Apache Ant, Apache Maven and sbt based projects as well as arbitrary shell scripts and Windows batch commands. The creator of Jenkins is Kohsuke Kawaguchi.[3] Released under the MIT License.Jenkins’ security depends on two factors: 1. access control 2. protection from external threats.

  1. Access control can be customized via two ways, user authentication and authorization.
  2. Protection from external threats such as CSRF attacks and malicious builds is supported as well.


It does not require any special kind of hardware, you’ll only need a CentOS 7 server and a root user access over it. You can switch from non root user to root user using sudo -i command.

Update System

It is highly recommended to install Jenkins on a freshly updated server. To upgrade available packages and system run below given command and it’ll do the job for you.

yum -y update

Install Java

Before going through the installation process of Jenkins you’ll need to set up Java Virtual Machine or JDK to your system. Simply run following command to install Java.

yum -y install java-1.8.0-openjdk.x86_64Once installation is finished you can check the version to confirm the installation, to do run following command.

java -versionThe above command will tell you about the installation details of java. By running the above command you should see the following result on your terminal screen.

openjdk version "1.8.0_131"
OpenJDK Runtime Environment (build 1.8.0_131-b12)
OpenJDK 64-Bit Server VM (build 25.131-b12, mixed mode)

Next, you’ll need to setup two environment variables JAVA_HOME and JRE_HOME and to do so run following commands one by one.

cp /etc/profile /etc/profile_backupecho 'export JAVA_HOME=/usr/lib/jvm/jre-1.8.0-openjdk' | sudo tee -a /etc/profileecho 'export JRE_HOME=/usr/lib/jvm/jre' | sudo tee -a /etc/profilesource /etc/profileFinally print them for review using following commands.

echo $JAVA_HOMEYou should see following output.


echo $JRE_HOME

shell scirpt


yum install -y java

wget -O /etc/yum.repos.d/jenkins.repo

rpm –import

yum install -y jenkins

yum install -y git

service jenkins start/stop/restart

chkconfig jenkins on



java -version

java -jar jenkins.war –httpPort=8080

# get jenkin-cli

wget http://localhost:8080/jnlpJars/jenkins-cli.jar

# jenkin-cli install plugin

java -jar jenkins-cli.jar -s http://localhost:8080 install-plugin checkstyle cloverphp crap4j dry htmlpublisher jdepend plot pmd violations warnings xunit –username=yang –password=lljkl

# safe restart

java -jar jenkins-cli.jar -s http://localhost:8080 safe-restart –username=yang –password=lljkl

Install Jenkins

We have installed all the dependencies required by Jenkins and now we are ready to install Jenkins. Run following commands to install latest stable release of Jenkins.

wget -O /etc/yum.repos.d/jenkins.repo --import above two commands will add the jenkins repository and also import the key. If in case you have previously imported the key from Jenkins then the rpm --import will fail because you already have a key. Please ignore that and move on.

Now run following command to install Jenkins on your server.

yum -y install jenkinsNext, you’ll need to start Jenkins services and set it to run at boot time and to do so use following commands.

systemctl start jenkins.servicesystemctl enable jenkins.service

Connecting to a Git Repo

You will probably want to connect to a git repository next. This is also somewhat dependent on the operating system you use, so I provide the steps to do this on CentOS as well:

  • Install git
sudo yum install git
  • Generate an SSH key on the server
ssh-keygen -t rsa
  • When prompted, save the SSH key under the following path (I got this idea from reading the comments here)
  • Assure that the .ssh directory is owned by the Jenkins user:
sudo chown -R jenkins:jenkins /var/lib/jenkins/.ssh
  • Copy the public generated key to your git server (or add it in the GitHub/BitBucket web interface)
  • Assure your git server is listed in the known_hosts file. In my case, since I am using BitBucket my /var/lib/jenkins/.ssh/known_hosts file contains something like the following, ssh-rsa [...]
  • You can now create a new project and use Git as the SCM. You don’t need to provide any git credentials. Jenkins pulls these automatically form the /var/lib/jenkins/.ssh directory. There are good instructions for this available here.

Connecting to GitHub

  • In the Jenkins web interface, click on Credentials and then select the Jenkins Global credentials. Add a credential for GitHub which includes your GitHub username and password.
  • In the Jenkins web interface, click on Manage Jenkins and then on Configure System. Then scroll down to GitHub and then under GitHub servers click the Advanced Button. Then click the button Manage additional GitHub actions.

  • In the popup select Convert login and password to token and follow the prompts. This will result in a new credential having been created. Save and reload the page.
  • Now go back to the GitHub servers section and now click to add an additional server. As credential, select the credential which you have just selected.
  • In the Jenkins web interface, click on New Item and then select GitHub organisation and connect it to your user account.

Any of your GitHub projects will be automatically added to Jenkins, if they contain a Jenkinsfile. Here is an example.

Connect with BitBucket

  • First, you will need to install the BitBucket plugin.
  • After it is installed, create a normal git project.
  • Go to the Configuration for this project and select the following option:

  • Log into BitBucket and create a webhook in the settings for your project pointing to your Jenkins server as follows: (note the slash at the end)

Testing a Java Project

Chances are high you would like to run tests against a Java project, in the following, some instructions to get that working:

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