Nail The DevOps Interview Using STAR Format (Situation, Task, Action, Result)

The STAR format stands for Situation, Task, Action, Result, and ensures a clear and impactful answer.

In this article, I will give you a few examples of what that means and how to answer the interview questions in your DevOps interview using the START format.

The STAR format stands for Situation, Task, Action, and Result.

• Situation: what happened?
• Task: What was my responsibility when the accident happened?
• Action: what actions I took in order to solve the accident.
• Result: how my action improved company performance and saved the company’s money.

Below are some common questions related to CI/CD, with suggested STAR-format answers.

Question 1: Can you describe a time when you implemented CI/CD from scratch for a project?

• Situation: When I joined XYZ Company, they were manually deploying applications, which took several hours and often led to production issues.
• Task: My role was to introduce and implement a CI/CD process to streamline deployments and reduce errors.
• Action: I evaluated several CI/CD tools and decided on Jenkins due to its compatibility with our tech stack. I integrated Jenkins with our code repository, set up automated builds and tests, and configured deployment pipelines. I also worked with the team to develop a branching strategy that facilitated continuous integration.
• Result: After implementation, we reduced deployment time from hours to minutes. Production issues related to deployments decreased by 80%.

To be honest, the question 1 scenario seems to me not entirely true, because nowadays even the newest and smallest companies have a basic CI/CD, but I decided to include it anyway in order to convey the idea of the STAR format to you. Probably more likely would be scenarios where you improve the CI/CD by adding automatic tests, security scans, artifact retention policies, etc.

Question 2: Describe a situation where a CI/CD pipeline you managed failed and how you addressed it.

• Situation: At ABC Corp., our CI/CD pipeline using Jenkins began failing during the testing phase. The failures were not consistent; sometimes it would pass, and at other times, it would fail on similar code changes.
• Task: As the DevOps engineer, I was responsible for ensuring the stability and reliability of our CI/CD processes. It was crucial to quickly identify the root cause of these intermittent failures to prevent disruptions in our deployment schedules.
• Action:

1. I first isolated the problem by checking if the failures were tied to specific types of code changes or specific developers’ commits, but there was no discernible pattern.
2. Digging into the Jenkins build logs, I noticed that the failures were always associated with timeouts during database connectivity checks in our test cases.
3. I talked with the database team and discovered that maintenance tasks, which caused brief database downtimes, were scheduled during the same time window our CI/CD pipeline was most active.
4. To address this, I coordinated with the database team to reschedule their maintenance activities during off-peak hours. Additionally, I introduced retry mechanisms in our test scripts to handle transient connectivity issues, ensuring that momentary hiccups wouldn’t fail the entire pipeline.

• Result: After these adjustments, our CI/CD pipeline became stable and consistent. Failures due to database connectivity dropped to zero, and the development team regained confidence in the pipeline’s reliability.

This answer is good because it shows the work between teams and your leadership and communication skills.

Question 3: How did you ensure the security of your CI/CD process?

• Situation: While working at ABC Inc., we identified potential security vulnerabilities in our CI/CD process.
• Task: I was tasked with reviewing and enhancing the security measures of our CI/CD pipeline.
• Action: I implemented several measures, including:

1. Securing our Jenkins server behind a firewall and allowing only necessary ports.
2. Integrating a static code analysis tool (SonarCloud) to check for security vulnerabilities in our codebase during builds.
3. Ensuring secret management using tools like HashiCorp Vault.
4. Regularly updating and patching our CI/CD tools to prevent known vulnerabilities.
5. Integrating Snyk to scan our artifacts.

• Result: These measures significantly enhanced the security of our CI/CD process, reducing the risk of potential breaches and ensuring safer deployments.

These are just a few examples, and depending on the specifics of the job you’re interviewing for, the questions might vary. Make sure to use real-life examples from your experience, and structure your responses using the STAR format to ensure a clear and impactful answer.Using real incidents from your professional experience will always resonate better with interviewers than hypothetical scenarios.

My suggestion is to take all the tools and products you are familiar with and prepare your answers in STAR format. Write them down in a notebook and remember them. Practice talking about it with your friend (make an example interview), record yourself answering the questions on video, and watch it.

Interviewing is a job in itself, and practice is the key.