Jenkins Continuous Deployment [With Practical Example]

Jenkins deployment is an accelerated process of complex automated software development. This article puts light on how Jenkins integrates all development life-cycle processes or DevOps stages such as building, documenting, testing, packaging, staging, deployment, static analysis, and many more, practiced in several organisations.

Today, many organizations are adopting DevOps in their offerings. In the software development life cycle, you must release the software continuously as a part of the project.

Tools such as Jenkins are widely popular for their potential to allow the applications’ continuous integration and delivery regardless of the platform. Jenkins is a free and one source tool that can handle any kind of build in Jenkins deployment, which will be discussed in the article.

Jenkins can be integrated with many testing and deployment technologies. This article describes how Jenkins is used for building and testing your software projects continuously.

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Thus, before diving into how Jenkins works, we need to understand the following topics that are the foundation for learning Jenkins:

• Continuous deployment
• Continuous delivery vs continuous deployment
• A practical example of Jenkins deployment
• Benefits of Jenkins deployment

Let’s have a look at all of them one by one!

Continuous Deployment

In continuous deployment, the software is released on the production servers continuously with automation. The code passes stages such as source code compilation, validating, review, packaging the application and performing unit testing and integration testing.

The code is then deployed on the test servers when the user acceptance test is performed. The software will be deployed on the production servers for software release. Read about continuous integration with jenkins.

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Continuous Delivery vs. Continuous Deployment

Continuous delivery and continuous deployment are two crucial stages of an SDLC in which the continuous delivery does not deploy to production for any changes. The developer needs to assure the code is deployable always and deploy it whenever needed.

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Continuous deployment needs every change automatically deployed, without any human arbitration.

In the above diagram, after the continuous integration stages are finished, the application built is automatically deployed on the production servers, which is nothing but constant deployment.

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Or else, if we are required for human approval to deploy the newer version to automating everything, we are executing a continuous delivery.

Due to this core difference, there have been several implications making each process suitable for different circumstances.

Jenkins

Jenkins is an open-source tool that accelerates the software process through an automation server used to continuously build and test software projects, enabling a CI/CD environment for the developers. It is written in Java thus really portable.

Jenkins has thousands of plugins and integrations. Hence, it is suitable for large projects requiring lots of customization. It supports version control tools such as Git, Maven, Mercurial, and Subversion.

A practical example of Jenkins deployment

Now that we have learned about what kind of tool Jenkins is and can be applied for a software development process for continuous deployment, let us now see how it works in a production environment.

First, Jenkins is set up on a server and a client’s project is added for build and test. The client can then download the application that has undergone testing. Deploying the project assets to a new location on the server can be tricky.

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For that, preliminarily, let’s assume a client project is set up on Jenkins, linked to your version control system.

Step 1: Creating a Jenkins Item

From the main menu, select ‘New item’ and name it. It will export the files from your client project to a server folder.

Step 2: Creating a post-build action

Go to the client project and select configure. Now,  originate a post-build action and choose ‘archive artifacts’ from the drop-down menu. Add the file types to be archived and exported.

After this, append another post-build action, ‘Build other project’ and enter the build item created before.

Archive

Step 3: Installing the plugin ‘Copy Artifact’

In the third step, you will install the Jenkins’ ‘Copy Artifact plugin’.

Go to ‘Project name’ for configuring and adding a build step. As the Copy Artifact plugin is installed, you will see the option ‘copy artifacts from another project’. Designate the folder to copy the artifacts and set the location path.

Set the location to “var/www/clients/..” . This will create a new folder on the server. Specify the path with an HTTP address(!).

Saving the Project

Step 4: Performing Testing

After the primary stages, now is the time to test the application.

For this, set off a build from the client project. This will prompt a new build. Check the deployment folder on the server. Here, you will see the files deployed.

But, even after all the actions, the build has failed and you got an error ‘FileException’.

Why?

Possible reasons can be:

• Jenkins did not have the permissions for writing to the folder and is unable to deploy the files.
• Link SSH to the server.
• Check the output folder permissions.
•  You will know, we faced an issue.

Perform the following steps to resolve this:

1. Add Jenkins to a group, here, the ‘www-data’ group.
2. Changing the ownership of the output folder to the ‘www-data’ group with the sudo chown command – R: ‘www–data’ clients.
3. Allow write access on the folder with the sudo chmod command .
4. Restart server and see the application deployed

What Benefits does Jenkins Offer?

• Jenkins is an open-source tool and provides excellent community support.
• Jenkins is relatively easy to install.
• Jenkins has 1000+ plugins. If a plugin is not available, you can code it easily.
• Jenkins is free of cost.
• Jenkins is built with Java; hence, portable to all the major platforms.

Also Read: Jenkins Project Ideas & Topics

Last Words

Jenkins is a robust Java written automation tool that has been widely used for Continuous Integration. With Jenkins, it is easier to build and test software projects continuously with what is written. It is the ultimate tool to deliver your software always by integrating with a large number of testing and deployment technologies.

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