20 CircleCI Interview Questions and Answers

CircleCI is a popular continuous integration and delivery platform that helps developers automate the software development process. If you are interviewing for a position that uses CircleCI, you can expect to be asked questions about your experience with the platform. In this article, we review some of the most common CircleCI interview questions and provide guidance on how to answer them.

CircleCI Interview Questions and Answers

Here are 20 commonly asked CircleCI interview questions and answers to prepare you for your interview:

1. What is CircleCI?

CircleCI is a continuous integration and delivery platform that helps software teams speed up the development process by automating the build, test, and deploy stages of the software development lifecycle.

2. How does CircleCI work?

CircleCI is a cloud-based continuous integration and delivery platform. It is used to build, test, and deploy software projects. CircleCI integrates with GitHub, Bitbucket, and other popular code repositories to automatically build and test code changes. It can also be used to deploy code to servers.

3. Can you explain the architecture of CircleCI?

CircleCI is a distributed system that consists of several different types of nodes, including build nodes, config nodes, and database nodes. The build nodes are where the actual builds take place. The config nodes store the configuration information for the system, and the database nodes store the data for the builds.

4. What are some of the main features of CircleCI?

CircleCI is a continuous integration and delivery platform that helps developers automate the process of building, testing, and deploying code. Some of the main features of CircleCI include its ability to run multiple jobs in parallel, its support for multiple languages and frameworks, and its ability to integrate with a variety of tools and services.

5. Is it possible to use 3rd party tools with CircleCI? If yes, then give me an example.

Yes, it is possible to use 3rd party tools with CircleCI. For example, you could use a tool like Jenkins to automate the testing and deployment of your code.

6. What’s the difference between a build and a job in CircleCI?

A build is a collection of jobs. A job is a unit of work that is run on a CircleCI server.

7. How do you configure CircleCI to run tests on multiple platforms like Linux, Windows, or MacOS?

You can configure CircleCI to run tests on multiple platforms by adding a config.yml file to your project’s .circleci directory. In this file, you can specify the platforms you want to test on and the commands that should be run on each platform. For example, you could have a config.yml file that looks like this:

platforms:
– linux
– windows
– macos

commands:
– run_tests_on_linux
– run_tests_on_windows
– run_tests_on_macos

8. How can you debug test failures when using CircleCI?

One way to debug test failures when using CircleCI is to use the “Rerun Failed Tests” feature. This will allow you to rerun only the tests that failed, which can help you pinpoint the problem. Another way to debug test failures is to use the “SSH Debugging” feature, which will give you access to a remote machine where you can run the tests again and examine the results in more detail.

9. What happens if a CI/CD pipeline fails?

If a CI/CD pipeline fails, it means that the code changes that were being tested did not meet the standards set by the development team. This could be due to a number of factors, such as failing tests, code that does not meet style guidelines, or code that is not compatible with the rest of the codebase. In any case, the pipeline will stop and the developers will need to fix the issues before the pipeline can continue.

10. What’s the recommended way of deploying code from CircleCI to production servers?

There are a few different ways to deploy code from CircleCI to production servers, but the recommended way is to use the CircleCI Deployment Orb. This orb will allow you to easily and quickly deploy your code to your production servers with just a few clicks.

11. What are some common issues that one might encounter when using CircleCI for automated testing?

There are a few common issues that can occur when using CircleCI for automated testing. One is that builds can take a long time to complete, which can be frustrating for developers. Another is that it can be difficult to get accurate test results, since CircleCI runs tests in parallel and there is no guarantee that all tests will be run on the same environment. Finally, it can be tricky to set up CircleCI to work with all the different tools and services that a development team might be using.

12. How can you set up test coverage reporting in CircleCI?

To set up test coverage reporting in CircleCI, you will need to use the “coverage” command. This will generate a report that will show you which lines of your code are covered by tests and which are not.

13. Is there a maximum number of projects that can be hosted on CircleCI?

There is no maximum number of projects that can be hosted on CircleCI.

14. What type of payment plans are available for CircleCI?

CircleCI offers both monthly and yearly payment plans. The monthly plan starts at $19/month for one user and one concurrent build, and the yearly plan starts at $150/year for one user and one concurrent build.

15. What are some alternatives to CircleCI?

Some popular alternatives to CircleCI include Jenkins, Travis CI, and AppVeyor.

16. What types of applications has CircleCI been used for? Give me some examples.

CircleCI has been used for a variety of applications, including web applications, mobile applications, and even some hardware applications. Some examples of applications that have been built using CircleCI include Facebook, Twitter, and Instagram.

17. Where should I store my project files when using CircleCI?

There are a few different options for storing project files when using CircleCI. One option is to use a cloud-based storage service like Dropbox or Google Drive. Another option is to use a version control system like Git or Mercurial. Finally, you can also use a local file system like your computer’s hard drive.

18. How do you connect GitHub repositories to CircleCI?

You can connect your GitHub repositories to CircleCI by going to the CircleCI website and clicking the “Add Projects” button. From there, you will be prompted to sign in with your GitHub account. Once you have signed in, you will be able to select which repositories you would like to connect to CircleCI.

19. How do you specify how many containers will be required to execute your jobs?

You can specify the number of containers required to execute your jobs in the CircleCI configuration file. In the file, you will need to add a “executor” key and set the value to the number of containers you need. For example, if you need two containers, you would add the following to your configuration file:

executor: 2

20. How do you create custom images in CircleCI?

You can create custom images in CircleCI by using the CircleCI API. You will need to create a file called .circleci/config.yml in your project’s root directory. In this file, you will need to add a “jobs” key and specify the “build” job. Under the “build” job, you will need to add a “steps” key and specify the “checkout” step. In the “checkout” step, you will need to add a “run” key and specify the “circleci/build” command. This command will pull down the CircleCI build image and run it in a container.