Day29- 90DaysOfDevOps

Hey Learners! Welcome back. Finally, we completed all the tasks related to Jenkins. Now it's time to move forward with some Interview questions and answers. Let's start...

1) What’s the difference between continuous integration, continuous delivery, and continuous deployment?

All these are related software development practices that focus on making the software development process more efficient and reliable. The main differences between these are:-

• Continuous Integration (CI):- It is the practice of regularly integrating code changes into a repository, usually multiple times a day. CI focuses on detecting and fixing integration issues.

• Continuous Delivery (CD):- It is the ability to release software to production at any time, with a simple push of a button.

• Continuous Deployment (CD):- Automatically deploy code changes to production every time they pass the tests, without any manual intervention.

2) Benefits of CI/CD

The benefits of CI/CD can be summarized as follows:-

3) What is meant by CI-CD?

CI/CD is the combined practice of continuous integration (CI) with continuous delivery or continuous deployment (CD). The purpose of CI/CD is to allow developers to deliver code changes more frequently and reliably by automating the build, test, and deployment processes.

4) What is Jenkins Pipeline?

Jenkins Pipeline is a suite of plugins that supports implementing and integrating continuous delivery pipelines into Jenkins. A continuous delivery pipeline is an automated expression of your process for getting software from version control right through to your users and customers.

A Jenkins pipeline consists of multiple stages, each representing a specific step in the software development process, such as building the code, running tests, and deploying the application. Each stage is defined using a series of steps, and the pipelines can be visualized and executed from within the Jenkins web interface.

5) How do you configure the job in Jenkins?

To configure a job in Jenkins, you need to perform the following steps:

1. Launch the Jenkins Web UI

2. Log in to Jenkins using credentials

3. Click "New Item" in the left navigation menu to create a job

4. Enter a name for a job

5. Choose a job type

6. Configure the job

7. Save the job

8. Build the job

6) Where do you find errors in Jenkins?

Whenever you build the job console output provides a detailed log of the build process, including any errors, or warnings that may occur during the execution of the job.

You can also find Jenkins generated log files which can be used to diagnose the issues and debug errors.

In the Jenkins Pipeline, the pipeline visualization provides a graphical representation of the build process in detail.

7) In Jenkins how can you find log files?

Manage Jenkins-> In system Information select System Log-> Log recorders and select All Jenkins Logs

You can have Build logs for each build separately as discussed in the above question. Go to Job-> From Build History select any build-> Got to console output

8) Jenkins workflow and write a script for this workflow?

Jenkins Workflow is a plugin that provides a suite of plugins that allows defining Jenkins continuous delivery pipelines using code as a script. The Jenkinsfile is written using a syntax based on the Groovy language and can include multiple stages with steps.

Example:-

pipeline {
    agent any

    stages {
        stage('Clone'){
            steps {
                echo "This is clonning stage"
            }
        }
        stage('Build'){
            steps {
                echo "This is Building stage"
            }
        }
        stage('Test'){
            steps {
                echo "This is Testing stage"
            }
        }
        stage('Deploy'){
            steps {
                echo "This is Deploying stage"
            }
        }
    }
}

9) How to create a continuous deployment in Jenkins?

Creating a deployment project means whatever changes are made(pushed) by developers should be deployed automatically. To do so follow the below steps

• Create a Jenkins project

  Go to Jenkins -> New Item -> choose Freestyle or Pipeline Project

• Set Up Source Code Management (SCM)

  Select SCM such as GIT

• Define Build steps

  to build your code such as cloning, building, testing, creating docker images, etc.

• Define Deployment Steps

  to deploy your code, such as copying the artefacts to the targeted server and executing scripts.

• Automate Build and Deployment

  Set up automatic triggers for the build and deployment steps

• Save and Build

  Save the configuration and build the pipeline to test

10) How to build a job in Jenkins?

To build a job you need to navigate to the Jenkins Dashboard and select the job you want to build. After selecting the required job in LHS select the Build Now option to build the job manually.

To automate the build whenever there are code changes set up triggers for that. To do so, instead of selecting the Build Now option select Configure. In Build Triggers select the appropriate option. (Build Periodically, GITScmPolling, Poll SCM, etc)

11) Why do we use a pipeline in Jenkins?

It simplifies the software delivery process by automating the build, test, and deployment steps. Jenkins Pipelines are used to automate the CI/CD and make it easier to implement complex builds and deployments.

12) Is Only Jenkins enough for automation?

For simple projects, Jenkins can be enough for automation, but for complex projects, additional tools may be required.

13) How will you handle secrets?

We can save our credentials in the Jenkins built-in credentials system which can be directly used in pipelines whenever needed. It can handle secrets such as usernames and passwords, API keys, Tokens, etc.

Manage Jenkins-> Security select Credentials-> global-> Add Credentials

14) Explain different stages in the CI-CD setup.

We can have stages in CI/Cd as per our requirements. The common stages involved in CI/CD setup are as er follows

1. Code Cloning:- Cloning the code from VCS

2. Code Build:- Building the cloned code

3. Code Test:- Testing the code

4. Code deploy:- Deploying the code

15) Name some of the plugins in Jenkin.

Plugins in Jenkins are an enhancement to the Jenkins system. They help extend Jenkins capabilities and integrate Jenkins with Other software.

According to the Jenkins community, there are around 1,500 plugins available for a wide range of uses.

Some of them are-

• Git plugin for version control integration

• Maven plugin for building and testing code

• Artifactory plugin for managing binary artefacts

• Pipeline plugin for continuous integration and delivery

• Blue Ocean plugin for a modern user interface

• EC2 plugin for dynamic provisioning of build agents

• SonarQube plugin for code analysis

Hope this questions helps you to crack your Jenkins Interview. Best luck!

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