Interview Questions for CI/CD i.e. Continuous Integration and Continuous Deployment

Master your CI/CD (Continuous Integration and Continuous Deployment) interview with 'Interview Questions for CI/CD.' This blog offers a thorough compilation of questions and answers, providing insights into CI/CD principles, tools, and best practices. It's an invaluable resource for software developers, DevOps professionals, and anyone aspiring to excel in roles focused on efficient, automated software development pipelines. Enhance your expertise and approach your interview with confidence.

1. What is CI/CD?

CI/CD stands for Continuous Integration and Continuous Deployment. It is a set of principles and practices that enable software development teams to deliver code changes more frequently and reliably.

2. Explain the difference between Continuous Integration and Continuous Deployment.

Continuous Integration (CI) is the practice of automatically integrating code changes from multiple contributors into a shared repository. Continuous Deployment (CD) goes a step further by automatically deploying the code changes to production after passing tests.

3. What is CI/CD pipeline?

CI/CD is a combination of continuous integration (CI) and continuous delivery (usually) or continuous deployment (rarely) in software engineering. Modern DevOps operations are built on the foundation of continuous integration and continuous delivery, or the CI/CD pipeline. You can automate your software delivery process with a CI/CD pipeline. As part of the pipeline, code is built, tests are run (CI), and a new version of the application is safely deployed (CD). By automating pipelines, manual errors are eliminated, developers are provided with standardized feedback loops, and iterating on products is made more efficient. In DevOps, continuous integration and continuous delivery (CI/CD) are best practices that ensure that code changes are delivered regularly and reliably.

4. Explain Continuous Integration, Continuous Delivery, and Continuous Deployment.

  • Continuous Integration (CI): Continuous integration (CI) is the practice of developers regularly integrating their code changes into a repository. Integration may take place several times a day and is verified by automated tests and a build process. As a result, integration challenges can be avoided, bugs can be found early in the development cycle, fixed, and tested iteratively. Every time new commits are integrated into the main branch, continuous integration emphasizes testing automation to make sure the application is not broken.
  • Continuous Delivery (CD): In continuous delivery, all code changes are automatically deployed to the test and/or production environments after the build is complete. Feature additions, configuration changes, and error fixes are some examples of changes. By automating the delivery of new code to users, CD ensures a safe, quick, sustainable process. The CD process also involves some additional checks, like performance tests in production. With Continuous Delivery, deployments are predictable and scheduled regularly.
  • Continuous Deployment (CD): The most critical stage of the pipeline is continuous deployment. By following this practice, you will be able to release all changes that have passed all stages of the production pipeline to your customers on time. Code changes can be made live much more quickly at this stage because there is little human interaction. In addition, continuous deployment allows you to accelerate your feedback loop with your customers and relieve pressure on your team since "release days" are no longer needed. Minutes after finishing their work, developers see their work go live.

5. Explain the benefit of the CI/CD Pipeline.

CI/CD brings certain benefits to your organization that will help you decide whether to go ahead with it. Below are some of these benefits:

  • CI/CD makes it possible to quickly integrate small code changes and test the changes easily.
  • With CI/CD setup, fault isolation is easier and faster. In fault isolation, the system is monitored, the fault occurrence time is determined, and the fault location is determined.
  • With CI/CD, MTTR (mean time to resolution) is reduced since changes are smaller and easier to implement. CI/CD setup increases the reliability of the unit and integration testing.
  • When CI/CD is set up, small code changes are merged very quickly and the code is ready for production very soon.
  • CI improves transparency by detecting early-stage failures like build failures, merge issues, integration test failures, etc.
  • CD facilitates the release of code to end-users.

6. What is a CI/CD Engineer?

CI/CD engineers can improve the integration and operation of CI/CD tools as well as ensure quality end-to-end integration systems. CI/CD Engineers would keep teams motivated and lead the charge on CI/CD. It is the CI/CD engineer's responsibility to ensure that CI/CD tools and platforms are functioning correctly within an organization. CI/CD engineers understand how to optimize their teams' development and release processes.

7. State difference between CI/CD vs DevOps.

DevOps and CI/CD differ in the following ways:

CI/CD DevOps
An important feature of CI/CD is its ability to automate and deliver code changes quickly and reliably.  The DevOps methodology is an approach to streamlining the development of products by integrating ideas, practices, processes, and technology.
CI/CD involves continuous automation and monitoring of the entire application lifecycle, starting with integration and testing and ending with delivery and deployment. As a result of CI/CD pipelines, organizations are able to minimize bottlenecks during software development and deployment. Organizations can implement DevOps methodologies to encourage rapid, continuous deployment of software by setting up their production teams and processes.
A continuous integration process optimizes the process of building, integrating, and testing code in a development environment. Continuous delivery is concerned with deploying code effectively in production. DevOps promotes minimizing waste and creating scalable, enduring systems.

9. Does CI/CD require any programming knowledge?

As far as CI/CD goes, it does not require any programming language or scripting language to be used. It is not necessary to use any programming or scripting language when you use a GUI-based tool like Azure DevOps (ADO). The use of ARM templates in Azure DevOps requires scripting knowledge. Therefore, it depends on the tools and different ways of setting up CI/CD.

10. What is Version Control?

Version control involves the use of a central repository where teammates can commit changes to files and sets of files. The purpose of version control is to track every line of code, and to share, review, and synchronize changes between team members. The following are some of the most popular version control tools:

  • Mercurial
  • Subversion (SVN)
  • Concurrent Version Systems (CVS)
  • Perforce
  • Bazaar
  • Bitkeeper
  • Fossil

11. What do you mean by Git Repository?

As part of the software development process, software projects are organized through Git repositories. In the repository, developers can keep track of all the files and changes in the project, so that they can navigate to any point in its history at any time.

12. Can you explain the Git branch?

The Git branch is essentially a separate line of development that can be used for working on a particular feature, usually during development. The use of branches allows developers to code without interfering with the work of other team members.

13. Describe the build stage.

The build stage is the first phase of the CI/CD pipeline, and it automates a lot of the steps that a typical developer goes through, such as installing tools, downloading dependencies, and compiling a project. Aside from building code, build automation involves the use of tools to verify that the code is safe and compliant with best practices. In this stage, the buildability and testability of the application are validated.

14. What does containerization mean?

As the term implies, containerization entails packaging together software code along with all the necessary components, such as frameworks, libraries, and other dependencies, in their own container. Among the advantages of containerization is that a container can be viewed as a fully packaged computing environment that can be transported in one piece.

15. Explain trunk-based development.

The trunk-based development approach ensures software remains up-to-date by integrating small, frequent updates into the main branch or a core "trunk". As a result of its ability to streamline merging and integration phases, it can be used to achieve CI/CD and to increase the speed and efficiency of the delivery of software and the efficiency of organizations. It is a branching model that consists of most of the work happening in a single trunk (also known as the trunk, master, or main). Each developer in the team merges their changes into the trunk on a daily basis. The reason why trunk-based development is popular is that it simplifies version control. This model minimizes merge conflicts due to the trunk's single source of truth.

16. Can a branch live for a long time?

Continuous integration follows trunk-based development practices, which means branches should be short-lived. Branch durations should be kept to a minimum of a few hours and a maximum of a day.

17. What is the difference between a hosted and a cloud-based CI/CD platform?

Hosted and Cloud-based CI/CD platforms differ in the following ways:

Hosted CI/CD platform Cloud-based CI/CD platform
It is necessary to manage a hosted CI server in the same way as any other server. Installation, configuration, and maintenance are all required before they can be used. Cloud-based CI platforms, however, do not require maintenance. An organization can immediately start using CI/CD platforms in the cloud without installing or configuring anything. 
Keeping the server secure requires updates and patches.  As the cloud is capable of providing all the machine power necessary, scalability is not an issue.
Additionally, failures in the CI server can halt development and deployment. The cloud SLA (service-level agreement) guarantees the reliability of the platform.

18. In CI/CD, does security play an important role? How does it get secured?

There are many factors that affect the security of CI/CD pipelines. These include:

  • The importance of unit testing cannot be overstated when it comes to the testing of multiple unit-testable distributed components. It is therefore important to unit test your code properly.
  • Static analysis security testing (SAST) scans your code for security vulnerabilities and the libraries you use. To ensure SAST scanning, all modern tools integrate well with the CD pipeline.
  • DAST (dynamic analysis security testing) is a tool for securing your application by dynamically scanning for security vulnerabilities. It simulates the actions of an attacker by performing the tests outside the application.

19. Explain some common practices of CI/CD.

To help you establish an efficient pipeline for CI/CD, here are some best practices:

  • Embrace the DevOps culture.
  • Ensure continuous integration is implemented and utilized.
  • Ensure the same deployment process is followed for every environment.
  • In the event that your pipeline fails, restart it.
  • Version control should be applied.
  • Incorporate the database into the pipeline.
  • Keep an eye on your continuous delivery pipeline.
  • Get your CD pipeline up and running.

20. In what way does testing fit into continuous integration? Is automated testing always a good idea?

The testing process is inextricably linked to continuous integration. Continuous feedback is the main benefit of CI for teams. Code developers test their code in the CI to ensure that it behaves as expected. Without testing, there would be no feedback loop to determine whether the application is release-ready.

21. Why is Automated Testing essential for CI/CD?

In order to ensure code quality, automation is an important characteristic of the CI/CD pipeline. The test automation process is used throughout the software development pipeline to identify dependencies and other issues, push changes to the different environments, and deploy applications into production. As part of its quality control role, the automation will assess everything from API usage and performance to security. In this manner, all changes made by team members are integrated comprehensively and implemented correctly.

  • With automated testing, we can run tests simultaneously across multiple servers/containers, resulting in a faster testing process.
  • Automated testing provides more consistency. Software automation eliminates human errors, and bias, and assures that it behaves as expected.
  • To meet changing demands, tools and frameworks in a CI/CD pipeline need to be adjusted quickly. Keeping up with updates and being agile is difficult with manual testing. However, most configurations are done automatically when you have automated tests. This allows you to migrate quickly to new environments.
  • Maximizing the workforce is crucial to a successful development project. Test automation frees engineers to work on other high-value tasks.
  • CI/CD pipelines require all the testing effort when small changes are made. Validating minor changes continuously is easier with automated testing.

22. What are the top testing tools in continuous testing?

An essential part of the CI/CD pipeline is continuous testing (CT). The developers are buffered by it, as it squashes bugs in a timely manner. This ensures that no matter how many releases take place, the end-user experience remains uncompromised. Despite accelerated processes, CT serves as a safety net that preserves the end-user experience. It must be seamlessly integrated into the software delivery pipeline since it is a continuous process. The following are the top testing tools used in continuous testing:

  • Testsigma
  • Selenium
  • IBM Rational Functional Tester
  • Tricentis Tosca
  • UFT (Unified Functional Testing)

23. What are some of the deployment strategies?

  • Regular release/deployment: Through a single release, the software is made available to the public.
  • Canary releases: These releases are intended to reduce the risk of failure by exposing a small fraction of the user base (around 1%) to the release. As part of a canary release, developers gradually transition users to the new release in a controlled manner.
  • Blue-green releases: Essentially, it involves running two instances of an application simultaneously; one is the current stable version, and the other is the most recent version. An immediate switch is made from the old version to the new one. If there is a problem, users can immediately revert to the previous version, which is safer than regular or big-bang releases.

24. Can you tell me about the serverless model?

There is a cloud-native approach to development known as serverless development, which allows developers to develop and run applications without requiring the management of servers. The server still exists serverless, but it is abstracted from application development.

25. What do you mean by Rolling Strategy?

Rolling deployments update running instances of an application with new releases as they are released. The process involves replacing old versions of an application over time with new versions of the application by replacing the entire infrastructure on which the application is run.

26. Code Snippet: Basic CI/CD Pipeline Configuration

# Sample CI/CD pipeline using a CI tool (e.g., Jenkins)

stages {
    stage('Build') {
        steps {
            // Build steps
    stage('Test') {
        steps {
            // Test steps
    stage('Deploy') {
        steps {
            // Deployment steps

27. Online Resources:

Published On: 2024-01-17