In this blog, I am going to cover the process of configuring Jenkins after installing it to automate the process of code deployment on a web server. I will set the Jenkins scheduler for 1 minute which will keep on checking the Git code on a given branch and as soon as the code on that branch changes, Jenkins will start the build process to deploy the code. I am taking an example of a demo project code and going to explain the process in a step by step way.

Setup on Deployment Server (Server A)
1) Create a shell script file as pull.sh on the home directory of the web server where you are going to deploy the code. Open the file and write the following script:

cd /var/www/html/project_directory

sudo git pull origin master

Save the script file and close it.

Setup on Jenkins Server (Server B)

1) Before configuring the Jenkins we need to install sshpass on the server where Jenkins is installed and for that, we need to run the following command:

sudo apt-get install sshpass

2) Now open the Jenkins on a browser by typing the URL and port of Jenkins:

http://192.168.xx.xx:8080

3) Log in to the Jenkins server by entering the username and password.

4) Click on the 'Create new job' link for creating a new job.

5) Under the item, name write the name of the job.

6) Click on the 'Freestyle project' click on the 'OK' button on the page. This will create a new job with the given name.

7) From the project, listing click on the project drop-down and click on 'configure' to configure the project.

8) Under Source Code Management selects the git option, please refer to the below screenshot:



9) Provide the repository URL and add credentials.

10) Under 'Branch Specifier' provide the Git branch name like:

*/master

11) Under build triggers select the Poll SCM and under schedule add * * * * * to pull every minute for any changes to deploy.

12)Under build click on execute shell to open the text area for executing the command. Enter the following command:

pwd
HOST=192.168.xx.xx
sshpass -p "password" ssh -T '-o StrictHostKeyChecking=no' username@$HOST sh pull.sh

If you want to know more about sshpass then click here.

13) Click on the apply button and then the save button.

Now, whenever new code is merged with the master branch Jenkins will initiate the build process automatically without any intervention. We can manually deploy the code by clicking on the 'Build Now' link from the left menu. If we want to see the deployment log then we can click on the build number or date under the 'Build History' section of the left menu. Anytime we can disable the project by clicking on the 'Disable Project' button of the project page.

We can configure SonarQube testing before code deployment through Jenkins which adds a code quality check before deployment but this I will explain in my next blog of Jenkins. If you want to know the Jenkins and SonarQube installation process and configuration then refer to my previous blog:

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Why SonarQube is important for IT projects ?  
SonarQube installation on Ubuntu 
Install Jenkins on Ubuntu  
Configure SonarQube Scanner with Jenkins
Analyze your project with SonarQube

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In that blog I have explained how we can install Jenkins on an Ubuntu the server now I am going to explain the process through which we can automatically deploy code from Git to a web server whenever there is a code merge in the master branch of Git. In case of any queries please leave a comment.