What is Jenkins? Jenkins Tutorial Guide to Beginners

Through continuous integration, various stages of DevOps can be integrated. Jenkins is a tool that can be used to integrate these stages of DevOps, it is quite popular these days. This blog article will cover the introduction part and some other details like features or benefits of using Jenkins throughout the article.

Jenkins is basically an open source continuous integration tool when it was launched but now after version update of Jenkins, it has become continuous integration and a continuous delivery tool that can organize application deployment phase too.

What is Jenkins?

Let's start with an introduction to one of the most popular DevOps tool that is popular as Jenkins. Jenkins is an open source tool that has many plug-ins and it is written in Java. The tool was launched to build and test the software projects in an easy way.

Developers can easily integrate application changes with this tool to help the user to obtain a fresh build. The software can be tested and delivered continuously with the help of various integration and deployment technologies.

Through automation, software developers can accelerate the process of software development. Jenkins mainly integrates all the stages of software development lifecycle that are documentation, packaging, testing, deployment, static analysis, and other ones.

Jenkins plugins help the developers in providing continuous integration and various stages can be integrated through Jenkins. To integrate any specific tool like Git, Amazon EC2, Manen 2 project, HTML publisher, etc. you can download the appropriate plugin and integrate the tool. It is a basically advantageous tool and the reason for advantages of Jenkins is:

• Jenkins is an open source tool that has wide community support
• Installation of Jenkins is quite easier
• A vast number of plugins are available; even if any plugin doesn’t exist then you can develop it and add it to the community.
• Due to Java written code, it is portable to major platforms.

Jenkins Continuous Integration

So far, we have discussed that Jenkins is a continuous integration tool, now let's take a quick look at this most used DevOps concept. In case of continuous integration, there is a shared repository in which developers can perform multiple changes even throughout the day and save them right there. As soon as the changes are committed, it gets stored in the repository and the team can easily detect if they found any problem due to that change.

Apart from the changes, there are several other operations like deployment of the application, testing it on the server, and providing it to the relevant teams after building and testing the results. All these steps can be performed as and when required by the DevOps team easily in a quick manner.

Learn the Key Metrics of Jenkins

There are several continuous integration tools in the market that makes the DevOps task easier and efficient. For the following metrics Jenkins is considered as best of them:

• Adoption: Jenkins has been adopted widely by DevOps professionals and so far, the tool has 147,000 active installations along with more than a million users across the globe.
• Plugins: Jenkins is popular due to the availability of many plugins around 100 to ease integration with most used tools for development, testing, and deployment.

Jenkins is a highly demanded tool globally and it can provide continuous integration just due to the availability of various plugins for several tools.

Jenkins Tutorial Guide - How the tool Supports Continuous Integration?

In case of software development lifecycle, the application has to be built and deployed on the test server for the testing purpose by the team members. It is quite popular and easy looking process for application development, but at the same time, this process has several flaws that need to be resolved. The so-called and mostly noticed flaws are like:

• To submit the supplication to test server developers have to wait for complete application development
• The test result can show multiple or number of bugs after the testing process and developers may need to check the entire source code to locate the bug.
• Software delivery process gets slow.
• Many feedbacks like any coding or architectural related issue or any missed release update message or file release upload or any build failure can be missed.
• Risk of frequent failure is increased due to complete manual process.

In short, we can say that as a result not only the delivery process gets slow but even the quality of the application can also be degraded due to all of these reasons. As a result, customer dissatisfaction may result. So, a platform that can overcome all of such shortcomings of the process was required by the developers that can provide the facility of continuous development and testing of the application, so that every change made to the source code can be triggered and altered. This process is known as CI and Jenkin tool is the one that can provide all of such CI features.

Let's see how Jenkins help the developers and testers? Following diagram shows the continuous integration with Jenkins: Above diagram shows the complete process of continuous integration that takes place in Jenkins:

• Firstly, developers make and commit any changes in the source code of the application that are stored in the Git repository. On the other side, Jenkin server keeps on checking any changes done and committed in the repository
• After any changes are done by developers they are detected by Jenkin server in source code repository. After tracking the changes Jenkin pulls the changes and start preparing a new built of the application.
• On failing of the build, the concerned team is notified about it
• Successful builds are deployed on test servers by Jenkins.
• The result of build formation and testing is sent to the developers as notification
• This complete cycle of changes and sending feedback keeps on repeating.

Now as we have understood working of Jenkins now let’s see what changes it has made from the earlier way of releasing and deploying an application. In the following scenario that is for before and after Jenkins:

Before Jenkins:

• When Jenkins was not there, entire source code was built and tested. The process of locating and fixing of bugs was quite long and difficult that many times even slows down the complete process of software delivery.
• Developers keep on waiting for the test result
• Complete deployment process was manual

After Jenkins:

• Every change or committed change of source code is tested as soon as it takes place. Developers now need not check the entire source code to locate any particular bug and frequent build releases are launched now
• The test result of every change of commit to the source code is informed to developers
• As soon as the changes are committed, Jenkin server can execute rest of the processes.

Learn Distributed Architecture of Jenkins:

For a distributed environment, Jenkins uses master-slave architecture to manage the builds. Here TCP/IP protocol is used to manage communication between master and slave units. Jenkins master and slave have following responsibilities:

Jenkins Master

Main Jenkin server is the master that has following responsibilities:

• To schedule job builds
• To dispatch builds to slaves for execution
• To monitor slaves online and offline as and when required
• To record and present the build results
• Master instance can also execute build jobs directly

Jenkins Slave

Jenkin Slave is a Java executable instance that is basically a remote machine. Jenkin slave has following characteristics:

• To hear the requests of Jenkin master instance
• Slaves can run on a variety of OS
• Slaves have to do the job as per direction that is given to them
• Any project can also be executed on a particular machine or slave machine. Jenkin can also pick the next available Slave machine for execution

Jenkin Tutorial Guide – What are the Features?

Jenkin is a continuous integration tool provides following features for the application deployment:

• Code pipelines
• Better UX and UI
• Improved plugins and security

Through a DSL Jenkins has introduced version builder that can help you to build, test and deploy various code pipelines. These pipeline scripts are easy to write, manage and execute. Parallel builds can be executed through these pipelines. You must have the control over how and what you are going to build.

As Jenkins provide better UI/UX so that user can easily visualize the flow and can easily configure passwords as and when required. You can also get a great view of Jenkin pipelines. Visual editor can be used to check and view these pipelines. The plugins are more safe and secure as well.

Final Words

DevOps has made the software development and deployment process quicker and easier, but for this, you may need certain tools. Jenkins is one of the most used DevOps tools that can ease the operations by providing multiple plugins and effective interface.

Better UI and tools like Jenkins is there to make the DevOps process easier. As it is an open source tool so can be used by anyone. To know more about DevOps and the related tools, you should join DevOps certification program at JanBask Training and explore your learning with the brightest minds.

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