What is CI/CD and how do you design a CI/CD pipeline?

Start by defining continuous integration and continuous delivery or deployment, and explain the goals of fast feedback and reliable releases. Describe stages like build, test, security scan, artifact storage, and deployment, and mention rollbacks and feature flags as safety measures. For example, you can implement a pipeline using Git, a CI server such as Jenkins or GitHub Actions, container builds pushed to a registry, automated tests, and staged deployments to canary then production. Keep the pipeline fast by parallelizing tests and caching dependencies, and avoid deploying untested changes directly to production by enforcing gating and review policies.

What is Infrastructure as Code and how would you choose Terraform or CloudFormation?

Explain Infrastructure as Code as the practice of defining cloud resources in declarative files so you can version and reproduce environments. Compare Terraform and CloudFormation on portability, provider support, and state management, noting Terraform is multi-cloud and CloudFormation is AWS-native. Give an example where you use Terraform modules to provision VPCs, subnets, and managed services with remote state in an S3 backend and state locking with DynamoDB. When choosing a tool, weigh team skills, existing vendor lock-in, and the need for multi-account or multi-cloud workflows.

How do you monitor systems and set up effective alerts?

Outline a monitoring strategy that includes metrics, logs, and traces, and explain alerting based on symptoms rather than raw infrastructure metrics. Describe using Prometheus for metrics with Grafana dashboards, and an ELK or Loki stack for log aggregation, then attach alerts to a pager or chat with severity levels. For example, set an alert for sustained error rate increases or latency above SLA, and tune thresholds to reduce noisy alerts by using rate windows and anomaly detection. Avoid alert fatigue by classifying alerts into pages, tickets, and informational messages, and run regular reviews to retire obsolete alerts.

Explain containerization and how you deploy containers at scale with Kubernetes.

Start by describing containers as isolated processes with their dependencies packaged together, and explain images, registries, and the runtime. Then explain Kubernetes concepts such as pods, deployments, services, ingress, and ConfigMaps, and how they enable scaling, self-healing, and rolling updates. Provide an example: build immutable images, push to a registry, create a deployment with resource requests and limits, expose it with a service, and use horizontal pod autoscaler for scale based on CPU or custom metrics. Watch for common pitfalls like missing resource limits, running everything as root, and ignoring readiness and liveness probes.

How do you manage secrets in infrastructure and pipelines?

Explain that secrets should never be stored in plain text in code or repos, and describe common patterns such as secret management services and short-lived credentials. Mention tools like HashiCorp Vault, cloud KMS combined with parameter stores, and secrets injected at runtime through environment variables or volume mounts. Give an example where CI fetches a short-lived token from Vault using an IAM role, then injects that token into the deployment environment just before start up. Avoid baking long-lived secrets into images or scripts, and enforce strict access controls with audit logging.

How do you approach incident response and postmortems?

Describe a structured incident response: detect, communicate, mitigate, and then analyze with a postmortem that focuses on facts and corrective actions. Explain the roles in an incident, the importance of an incident commander, and clear communication channels so engineers can focus on remediation while stakeholders are informed. For example, during a database outage you might fail over to a replica, open an incident channel with status updates every 15 minutes, and after recovery run a blameless postmortem that resulted in improved automated failover and runbook updates. Emphasize learning from incidents by tracking action items to completion and measuring whether they reduce recurrence.

What strategies do you use for scaling applications and infrastructure?

Begin by separating vertical scaling versus horizontal scaling and explain choosing one based on cost, load patterns, and statefulness of the service. Discuss techniques such as autoscaling groups, stateless application design, caching layers, database read replicas, and queueing to smooth spikes in load. Give a concrete example: move session state to Redis, add a load balancer with autoscaling based on latency and queue length, and shard the datastore as traffic grows. Watch for scaling bottlenecks like single-point databases, synchronous calls between services, and insufficient capacity planning.

How do you manage configuration across environments?

Explain the principle of treating configuration as code and keeping environment-specific values separate from application code. Describe tools and patterns such as Consul, ConfigMaps in Kubernetes, or templated files injected at deploy time, and stress versioning of config changes. Offer an example where you maintain a common configuration template, override environment values in a secure store, and test configuration changes in staging before production. Avoid hardcoding environment-specific values, and include validation checks so bad configuration does not reach production.

How do you secure infrastructure and what practices do you follow?

Start with a defense-in-depth approach that includes network segmentation, least privilege IAM roles, encrypted communications, and regular patching. Describe automated tooling for compliance scanning, container image scanning, and vulnerability management, and combine that with access reviews and multi-factor authentication. For example, enforce private subnets for databases, use security groups and IAM policies with least privilege, and run daily image scans as part of the CI pipeline. Avoid broad network access rules, shared accounts, and delayed patching cycles that increase exposure.

How can you speed up CI pipelines and reduce build times?

Outline tactics like caching dependencies, parallelizing test suites, splitting long pipelines into smaller stages, and running expensive integration tests less frequently. Explain using build artifact caches, test sharding across runners, and conditional steps that only run when relevant files change. For example, cache dependency directories in Docker builds, run unit tests in parallel across runners, and only trigger full system tests on main branch or nightly builds. Be careful not to sacrifice test coverage for speed without measuring risk, and monitor pipeline flakiness to avoid wasting developer time.

Tell me about a time you handled a major production outage.

Situation and Task: Our primary API cluster experienced increased latency and error rates during peak traffic, and customers were reporting timeouts. I was on call and acting as incident commander, tasked with restoring service quickly while keeping stakeholders informed. Action: I directed a quick triage to identify a slow database query, initiated a temporary rollback to the previous release, and coordinated with the database team to add an index and increase read replica capacity. Result: The rollback and index reduced error rates to normal within 20 minutes, customer impact was minimized, and the postmortem led to a permanent fix plus an alert that caught similar regressions earlier.

Describe a time you improved a deployment process.

Situation and Task: Our team had frequent failed deployments because manual steps were error prone, and we needed to reduce lead time and rollback risk. I led an effort to automate the pipeline and introduce staged rollouts with health checks. Action: I implemented automated blue green deployments, added automated integration tests to the pipeline, and created a runbook for rollbacks and database migrations that required approval. Result: Deployments became more predictable, deployment failures dropped by a measurable amount, and team confidence improved because we could safely rollback with documented steps.

Tell me about a time you resolved a conflict on a cross-functional team.

Situation and Task: A developer wanted to push a risky optimization just before a major release, while QA and operations were concerned about stability, creating tension across teams. As the devops engineer, I needed to balance speed and reliability and find a path forward everyone accepted. Action: I organized a technical meeting, had the developer present the change with benchmarks, proposed an A B test in staging and a limited canary in production, and defined clear rollback criteria. Result: We ran a controlled canary that validated the optimization with no customer impact, the change was gradually rolled out, and the process improved trust between teams by giving a repeatable validation path.

devops Interview Questions: Complete Guide

You should expect a mix of system design, tooling, scripting, and incident management questions when preparing for devops interview questions. Interviews often include live problem solving, take-home tasks, and behavioral rounds, so plan to show both technical depth and on-call experience. Stay calm, explain your tradeoffs, and connect your answers to real systems you have managed.

Common Interview Questions

Behavioral Questions (STAR Method)

STAR Method: Structure your answers using Situation, Task, Action, and Result to tell compelling stories about your experience.

Questions to Ask the Interviewer

Show your interest by asking thoughtful questions

•What does success look like in this role after the first six months, particularly for operational metrics?
•How is the on-call rotation structured and what support is available for on-call incidents?
•Can you describe the current CI/CD tooling and any constraints the team faces with deployments?
•What are the biggest reliability or scalability challenges the team expects to solve in the next year?
•How do teams run postmortems and track action items after incidents to ensure follow through?

Interview Preparation Tips

Practice explaining tradeoffs out loud, because interviewers want to hear your reasoning, not just the final answer.

Bring specific examples from your experience, such as a pipeline you built or an incident you handled, and include metrics when possible.

When asked whiteboard or design questions, outline requirements and constraints first, then propose incremental solutions rather than a single big design.

Prepare a short story for common behavioral topics like outages, deployments, and cross-team conflict using the STAR structure so your answers remain concise and factual.

Overview: What to Expect in DevOps Interviews

DevOps interviews test both technical skill and systems thinking. Expect questions that cover continuous integration/delivery (CI/CD), infrastructure as code, containers and orchestration, monitoring and observability, scripting, and cloud platforms.

Interviewers commonly probe for concrete results — for example, "Describe a pipeline you built that cut deployment time by X%" — so quantify outcomes when you answer.

Typical formats include:

•Live coding or scripting (Bash, Python) for 20–40 minutes.
•Whiteboard or take-home design: design a CI/CD flow or system architecture for 30–60 minutes.
•Troubleshooting exercises: debug a failing container, identify a root cause from logs.
•Behavioral questions on incident response and collaboration.

Use the four DORA metrics to structure answers when relevant: deployment frequency, lead time for changes, mean time to restore (MTTR), and change failure rate. For context, high-performing teams deploy multiple times per day, keep lead time under one day, and maintain change failure rates in the 0–15% range.

Prepare real examples with numbers: e. g.

, "Reduced build time from 20 to 12 minutes (40%) by adding dependency caching and parallel tests. " Practice clear diagrams for system designs and keep a one-page cheat sheet of commands for Docker, kubectl, Terraform, and Git.

Actionable takeaway: prepare 3—5 case studies with metrics, a short architecture diagram for each, and 10 common commands you can type from memory.

Key Subtopics to Master (with Examples and Skill Levels)

Break your prep into focused subtopics and measure proficiency by examples you can demonstrate.

1) CI/CD pipelines (25% of typical interviews)

•Skills: YAML for pipelines, artifact storage, canary/blue-green deploys, rollback.
•Example task: build a GitLab CI pipeline that runs tests, builds a Docker image, pushes to registry, and deploys to Kubernetes with a health check. Expect to explain steps and failure modes.
•Proficiency: Junior = single-service pipeline; Mid = multi-service pipelines with artifact versioning; Senior = pipelines that support canary releases and automated rollbacks.

2) Containers & Orchestration (20%)

•Skills: Dockerfile optimization, multi-stage builds, kubectl, Helm, namespaces.
•Example question: "Why does Pod OOM occur? How would you fix it and prevent regressions–

3) Infrastructure as Code (20%)

•Tools: Terraform, CloudFormation. Show a 20–100 line Terraform module that provisions networking + 2 EC2 instances or an EKS cluster.

4) Monitoring & Logging (15%)

•Tools: Prometheus, Grafana, ELK. Be ready to write an alert rule and explain a runbook.

5) Scripting & Automation (10%)

•Show small scripts that rotate logs or automate backups.

6) Cloud & Security (10%)

•Expect IAM scenarios, least privilege examples, and secret management (Vault, AWS Secrets Manager).

Actionable takeaway: allocate study time in the same percentage mix above and prepare one concrete example per subtopic.

Best Resources and a 4-Week Practice Plan

Use targeted resources and a time-boxed plan to gain measurable progress.

High-value resources (concise):

•Books: "The DevOps Handbook" (practical practices), "Kubernetes Up & Running" (cluster concepts).
•Courses: Coursera or Pluralsight courses on CI/CD and Kubernetes; KodeKloud or Udemy hands-on labs for practice.
•Official docs: Terraform Registry examples, Kubernetes docs, and AWS EKS guides for accurate commands.
•Reports: DORA Accelerate and State of DevOps summaries for metrics and industry norms.
•Practice platforms: Katacoda scenarios, Play with Kubernetes, GitHub Actions marketplace for pipeline examples.

Suggested 4-week plan (40 hours total):

•Week 1 (10h): CI/CD basics — create a pipeline for one microservice; add tests and artifact storage.
•Week 2 (10h): Containers & Kubernetes — Dockerize the app, deploy to a single-node cluster; fix a failing pod.
•Week 3 (10h): IaC & Cloud — write a Terraform module to provision infrastructure and deploy the app.
•Week 4 (10h): Monitoring, security, and mock interviews — add Prometheus metrics, build an alert, and run 3 mock interviews focusing on design and incident response.

Certifications to consider: AWS Certified DevOps Engineer or Certified Kubernetes Administrator (CKA) if you want formal proof of skills.

Actionable takeaway: follow the 4-week plan, log outcomes with numbers (e. g.

, build times, deploy frequency), and run at least three live mock interviews.

devops Interview Questions: Complete Guide

Emily Thompson

Common Interview Questions

Behavioral Questions (STAR Method)

Questions to Ask the Interviewer

Interview Preparation Tips

Overview: What to Expect in DevOps Interviews

Key Subtopics to Master (with Examples and Skill Levels)

Best Resources and a 4-Week Practice Plan

Common Interview Questions

Build your job search toolkit

devops Interview Questions: Complete Guide

Emily Thompson

Common Interview Questions

Q1What is CI/CD and how do you design a CI/CD pipeline?

Q2What is Infrastructure as Code and how would you choose Terraform or CloudFormation?

Q3How do you monitor systems and set up effective alerts?

Q4Explain containerization and how you deploy containers at scale with Kubernetes.

Q5How do you manage secrets in infrastructure and pipelines?

Q6How do you approach incident response and postmortems?

Q7What strategies do you use for scaling applications and infrastructure?

Q8How do you manage configuration across environments?

Q9How do you secure infrastructure and what practices do you follow?

Q10How can you speed up CI pipelines and reduce build times?

Behavioral Questions (STAR Method)

B1Tell me about a time you handled a major production outage.

B2Describe a time you improved a deployment process.

B3Tell me about a time you resolved a conflict on a cross-functional team.

Questions to Ask the Interviewer

Interview Preparation Tips

Overview: What to Expect in DevOps Interviews

Key Subtopics to Master (with Examples and Skill Levels)

Best Resources and a 4-Week Practice Plan

Common Interview Questions

Build your job search toolkit