It’s a software construction and testing tool that’s free and open source. Developers will find it simple to integrate changes into the project using Jenkins. If there are any changes, Jenkins’ main responsibility is maintaining track of the version control system and starting and monitoring a build system. It keeps an eye on the whole process and sends reports, alerts and notifications.

Developers and testers use Jenkins for several reasons, including the following:

• Developers and testers use Jenkins to detect flaws in software development processes and automate testing procedures.
• They utilize it to integrate changes into the build while monitoring the code in real-time.
• Because of its plugin capabilities and simplicity of use, Jenkins is a good match for establishing a CI/CD pipeline.

• It’s an open-source automation application that’s free to use.
• There are a lot of plugins provided by Jenkins.
• It’s simple to get going and put in place on various platforms.
• Provides pipeline support
• Fast release cycles
• Easy upgrades

• As a coding language for Java platforms, Apache Groovy is a dynamic object-oriented programming language.
• Groovy is employed to enable diverse teams to contribute to the project in distinct languages and orchestrate the Jenkins pipeline.
• Groovy’s syntax is akin to Java’s, which makes it easier to integrate with the Java API..
• Java compatibility and Development support are two features of the language.

• Install Java
• Install Apache Tomcat Server
• Download Jenkins war File
• Deploy Jenkins war File

Here are the commands used to start Jenkins:

• Open the command prompt
• Browse to the location where Jenkins war is present after the command prompt has opened.
• Then run the command:

D:\>Java -jar Jenkins.war

• Continuous Integration is a method of code integration that entails putting the codes into a shared repository.
• For the early detection of code problems, the practice uses automated verifications.
• Continuous Integration causes the program to check for and locate bugs.
• It gives the construction process consistency.
• It’s a method for developing software that prevents error.

• All of the tasks in the SDLC and DevOps life cycle are delivered and integrated continuously through this pipeline.
• Continuous delivery pipelines are implemented and integrated into Jenkins with the help of the Jenkins pipeline, a collection of plugins. Jenkins connects this pipeline in a specific way.
• The Jenkins pipeline solves a number of challenges, including keeping track of thousands of jobs and needing to resort to additional powerful techniques for maintaining deployment.

• CI/CD pipeline
• Scripted pipeline
• Declarative pipeline

• From the menu, choose New.
• Next, you can choose from a variety of free-style jobs.
• To form a new job, simply click on OK.
• As a result, you will be able to adjust your job on the following page.

• A source code repository, such as a Git repository, for example.
• A Maven script, for example, contains a build script.

• Version Control systems like Git and SVN (Apache Subversion)
• Build tools like Maven

• Maven 2 project
• Amazon EC2
• Copy artifact
• Join
• HTML publisher
• Green Balls

• Jenkins saves all of his settings, creates scripts, and keeps track of his activity in his home directory.
• Then, all you have to do is copy this directory if you want to make a backup of this Jenkins installation.
• To clone a job or rename the directory, you may copy the job directory.

Continuous Integration: Continuous Integration (CI) is a DevOps software development methodology that allows programmers to combine and merge changes in the central repository to execute automated builds and tests.

Continuous Delivery: The development, testing, and delivery of software code improvements are known as Continuous Delivery (CD). The fact that the code is always deployed is the most crucial aspect of the CD.

Continuous Deployment: The final stage in the DevOps pipeline is Continuous Deployment (CD). The term “automatic push” refers to the process of transferring developer modifications from the source to the staging environment.

You must do the following steps if you want to deploy a custom version of a core plugin:

• Stop Jenkins
• Then, in $Jenkins_Home/plugins, copy the custom HPI.
• After that, the plugin directory has been deleted.
• Next, create a file named .hpi.pinned that is empty.
• Finally, start Jenkins

• By copying the appropriate job directory, you may migrate a task from one Jenkins instance to another.
• By creating a clone of the job directory with an unusual name, you may create a copy of an already existing job.
• Renaming a directory is another way to rename a current job.

• TeamCity
• Travis CI
• Go CD
• Bamboo
• GitLab CI
• CircleCI
• Codeship

• Developers must keep their code secure on a regular basis, and Jenkins monitors changes in repositories.
• Jenkins detects and uses the changes once they’ve been specified.
• Jenkins will then proceed through its traditional pipeline of stages after that. The procedure will progress to the next phase as one step is completed.
• The Jenkins build will halt there if a stage fails, and the team will be notified via email. The code will be implemented in the proper server once it has been successfully completed.
• Jenkins tells the team about the results of the successful testing phase using it.

Maven:

• Build tool
• Perform build operations

ANT:

• Build tool
• Perform build operations

Jenkins:

• Continuous Integration tool
• Jenkins may run unit tests and deploy applications

Bamboo:

• Commercial tool
• Dedicated development team
• Comparatively more user friendly
• Many built-in features and plugins are available in the Atlassian marketplace.

Jenkins:

• Open-source tool
• Huge global community
• Less user-friendly
• Many plugins to perform different functions

Jenkins:

• Jenkins is a free open-source Continuous Integration server.
• Forked by Hudson
• Used by companies like Netflix, Facebook, eBay, Instacart, LinkedIn, etc.
• Jenkins supports a lot of plugins

Hudson

• Hudson is an extensible Continuous Integration server
• Continuous Integration tool
• Used by companies like Logo Yazilim, TableAir UAB and OptoSweden AB.
• Hudson supports a lesser number of plugins

• First, create a new Jenkins job and open the Jenkins dashboard.
• Now, enter the desired project name and select the job type.
• Click on OK.
• Then enter the project information.
• After that, visit the ‘Source Code Management’ tab.
• If the Git plugin is pre-installed in Jenkins, there will be ‘Git’.
• If it is not installed, you must reinstall the plugins (GitHub plugin, GitHub Branch Source plugin, GitHub API plugin, Git client plugin, etc.).
• After we install the plugins, restart Jenkins.
• To check if Git is installed, you can go to Command Prompt and type Git, and you would see various options like usage, version, help, etc.

• Kubernetes is a portable and open-source platform that is used for managing workloads and services that are containerized.
• With the help of Kubernetes, the group of hosts running the Linux containers can be easily and efficiently managed.
• To manage a Continuous Delivery (CD) pipeline, the most efficient way is to deploy Jenkins with Kubernetes Engine.
• Kubernetes enables the creation of multiple container instances to satisfy more fault tolerance.
• Kubernetes deploy plug may be used with Jenkins for Continuous Deployment.

• Install the third-party software
• Then install a Jenkins plugin supporting the third-party tool
• Now, configure the tool from the Manage Jenkins section
• Finally, your plugin is ready to be used

• $JOB_NAME - The name that you give your job when it is first set up.
• $NODE_NAME - This is the name of the node on which the current build is running.
• $WORKSPACE - Refers to the path of the workspace
• $BUILD_URL - Indicates the URL where the results of the builds can be found.
• $JENKINS_URL - This is set to the URL of the Jenkins master that is responsible for running the build.

• Pipeline: User-defined model of a CD pipeline. Pipeline’s code takes the role of defining the entire build process, including building, testing, and delivering an application.
• Node: A machine as a part of the Jenkins environment which is capable of executing a pipeline.
• Step: An individual task that communicates to Jenkins about what to do at a particular point in time
• Stage: This defines distinct subset of tasks that are conceptually unique and performed through the pipeline (build, test, deploy stages)

The steps to deploy a custom build of a core plugin are:

• First, copy the .hpi file to $JENKINS_HOME/plugins
• Then remove the plugin’s development directory
• Next, create an empty file called .hpi.pinned
• Finally, restart Jenkins and use your custom build of a core plugin

• Open the Jenkins dashboard and create a new item by clicking on ‘new item’
• Enter the project name and, from the options, select ‘Multibranch pipeline’
• Click on OK
• Then select the repository location, branch source (GitHub/Bitbucket), and add the branch source credentials.
• Save the project
• Now, Jenkins automatically creates new Multibranch Pipelines for repositories
• Then to connect to the GitHub repo, we need the HookURL
• To get this URL from the repository settings, add this HookURL to the Webhooks section
• Once the jobs are created, Jenkins will automatically trigger the build

In Jenkins, a build can take many input parameters to execute.

• To define parameters for the job, select the “this project is parameterized” box.
• The drop down “Add Parameter” is enabled with the parameter types list. Any number of parameters may be added in the list.

There are several parameter types provided in the list.

• Browser–If we launch the Jenkins node agent from a browser, a Java Web Start or JNLP file is downloaded. The downloaded file launches a new process on the client machine to run jobs.
• Command-line–If you want to start the node agent using the command line, you need the executable agent.jar file. When this file runs, it launches a client’s process to communicate with the Jenkins master to run build jobs.

• JENKINS_HOME directory is the place where all the settings, logs, and configurations are stored. It stores all this information in XML files.
• The directory contains a subdirectory for every Jenkins build job being operated.
• Every directory has two subdirectories: builds and workspace., and some other files as well.
• These sub directories are important, as the workspace directory is located at the place where Jenkins is building the project, and it contains the source code.
• The builds directory stores the history of all the builds performed for this job.

• Jenkins uses an internal database to store user data and credentials.
• Jenkins can use a lightweight Directory Access Protocol (LDAP) server to authenticate users.
• We can configure Jenkins to employ the application server’s authentication mechanism upon which we deploy it.