Technical Assessment Preparation: The Complete Developer Guide for 2025

DevOps Engineer Interview Preparation Guide

Written by Diana Pavaloi | Dec 4, 2025 10:22:32 AM

DevOps remains one of the most sought-after skill sets today. With companies shifting rapidly toward cloud infrastructure, CI/CD automation, containerisation, and platform engineering, demand for strong DevOps engineers is at an all-time high — and so is the competition.

According to the 2024 Puppet State of DevOps Report, 58% of organisations say Platform Engineering increases productivity, and 50% report faster product delivery — two of the core outcomes strong DevOps teams are expected to drive.

This guide breaks down the most common DevOps interview questions, real-world scenarios, and practical examples you'll be expected to navigate, from Kubernetes troubleshooting and Terraform fundamentals to CI/CD pipelines and cloud architecture. But DevOps interviews aren’t only about technical depth. Cultural fit matters just as much, and interviewers want to understand how you collaborate, communicate, handle pressure, and contribute to a healthy engineering culture.

Later in this guide, you’ll find a full section on behavioural questions and example answers to help you prepare for that part of the process too.

What's inside:

  • Core DevOps concepts and interview strategies

  • CI/CD, GitOps and automation fundamentals

  • Cloud platforms: AWS, Azure, GCP (with real scenarios)

  • Containers, Kubernetes, Helm, and service orchestration

  • Infrastructure as Code (Terraform, CloudFormation)

  • Observability, monitoring and SRE-style questions

  • Real-world troubleshooting and incident questions

  • Senior-level architecture and system design

  • Sample coding/scripting challenges (Bash, Python)

Use this as your go-to resource for any DevOps or platform engineering interview.

For broader preparation, explore our comprehensive Technical Assessment Preparation Guide. 

Core DevOps concepts and interview strategies

Most DevOps interviews start with fundamentals: reliability, automation, collaboration, and continuous delivery. Expect interviewers to test not just your tooling knowledge, but your mental model of how modern engineering teams ship software.

Sample interview question: What does DevOps mean to you?

Example answer:

"DevOps is about shortening the path from idea to production by improving collaboration between dev and ops, automating repeatable steps, and building systems that are reliable and observable. In my last role, we reduced deployment time from hours to minutes by introducing CI/CD, automated testing, and better alerting."

Other fundamentals that often come up:

  • CI vs CD vs continuous deployment

  • Immutable infrastructure

  • Blue-green vs rolling deployments

  • Secrets management

  • Shift-left testing and security

Tip: Keep a few real examples ready: a deployment pipeline you built, a flaky service you stabilised, or a monitoring setup you improved.

CI/CD and automation

CI/CD is at the heart of modern DevOps practice. Interviewers want to know whether you can design pipelines that are reliable, secure, and fast enough to support real engineering teams.

For additional context on how CI/CD ties into API lifecycles and backend workflows, the Backend Engineer Interview Guide offers helpful examples you can build on.

Sample question: How do you design a CI/CD pipeline for a microservices application?

Strong answer structure:

  • Triggers: PR events, branch protection rules, semantic versioning

  • Build stage: dependency caching, parallel builds, artefact packaging

  • Automated testing: unit, integration, contract tests, API tests

  • Security: SAST, SCA, container scanning, signing images

  • Deployment: blue/green, rolling, canary releases; environment-specific configs

  • Post‑deploy checks: health checks, smoke tests, automated rollbacks

  • Observability hooks: logs, metrics, and tracing from deployment events

Practical example you can reuse:

"At my last job, we re-architected our CI/CD so that services built in parallel, ran fast unit tests first, and only triggered integration tests for changed modules. Deployments used a progressive rollout where 5% of traffic hit the new version before full rollout. This reduced incidents and cut total pipeline time from 18 minutes to 6."

Useful tools to mention:

  • GitHub Actions, GitLab CI, Jenkins, CircleCI

  • ArgoCD for GitOps-style deployments

  • ECR/ACR/GCR for image storage

  • OPA or Conftest for pipeline governance

Mini challenge: Write a workflow that builds a Docker image, runs tests, signs the image, pushes it to ECR, and triggers a canary deployment on Kubernetes.: Write a GitHub Actions workflow that builds a Docker image, runs tests, and pushes it to ECR.

Containers, orchestration and Kubernetes

Most DevOps teams rely heavily on Kubernetes, so expect deep questions on cluster design, debugging, deployments, and optimisation.

Sample question: How would you troubleshoot a CrashLoopBackOff?

Good approach:

  • Run kubectl describe pod to inspect events

  • Check liveness/readiness probe failures

  • Inspect logs using kubectl logs

  • Verify env vars, config maps, and secret mounts

  • Inspect resource limits—OOMKilled is common

  • Inspect container startup commands and entrypoints

Follow-up interview question you may get: What if the pod logs show nothing?

  • Check init containers

  • Check image pull issues

  • Verify permissions/service accounts

  • Look at node-level issues

Other Kubernetes topics to review:

  • Cluster architecture: control plane vs nodes

  • Deployments vs StatefulSets vs DaemonSets

  • Horizontal/vertical autoscalers

  • Network Policies and service-to-service communication

  • Pod disruption budgets

  • Namespace strategies and multi-tenancy

  • Helm chart design and templating

If you want to strengthen your understanding of distributed systems and how Kubernetes concepts map to high-level architecture discussions, explore our System Design Interview Preparation Guide.

Example of something strong to say:

"We reduced cluster costs by 32% by right-sizing memory limits, switching large workloads to spot nodes, and using pod autoscaling more intelligently."

Pro tip: Interviewers love real-world K8s migration or optimisation stories—bring one.: If you've migrated services to K8s or reduced cluster costs with better autoscaling, talk about it.

Cloud platforms: AWS, Azure, GCP

Most DevOps interviews assume at least one cloud provider. What they want to see is whether you understand how services work together, and when to choose one architecture over another.

Sample question: Design a scalable, highly available service on AWS.

Interviewers expect you to mention:

  • Networking: VPC, subnets, route tables, NAT gateways, security groups

  • Compute: EC2 vs Fargate vs Lambda; when to pick each

  • Storage: RDS, DynamoDB, S3 lifecycle rules, backups

  • Security: IAM roles, least privilege, KMS

  • Reliability: Multi-AZ setups, autoscaling, load balancers

  • Monitoring: CloudWatch metrics, logs, alarms

What great candidates add:

  • Cost considerations (e.g., NAT costs, storage tiers)

  • Deployment strategies (e.g., blue/green with ALB)

  • Disaster recovery (RPO/RTO, cross-region replication)

  • Caching (CloudFront, ElastiCache)

Strong example line:

"To keep costs predictable, we used DynamoDB on-demand for spiky workloads and added TTL-based expiration to reduce storage."

Infrastructure as Code (IaC)

IaC is one of the strongest signals of DevOps maturity. Terraform remains the most commonly tested.

Sample question: How do you structure Terraform for a large system?

Strong answer structure:

  • Break infrastructure into versioned modules

  • Use remote state (S3 + DynamoDB, Terraform Cloud)

  • Enforce format, validate, plan in CI

  • Use workspaces or separate directories per environment

  • Pin provider versions to avoid breaking updates

  • Use policy-as-code for governance

Example talking point:

"We introduced a module registry that every team used, ensuring shared patterns for VPCs, IAM roles, and databases. This reduced security issues and drift across environments."

Other IaC topics:

  • Detecting drift automatically

  • Using depends_on carefully to avoid unnecessary rebuilds

  • Handling secrets with SSM, Vault, or Secret Manager

  • Importing existing cloud resources safely)

Observability, monitoring and incident response

This is often the make-or-break section for senior candidates.

Sample question: How do you design an alerting system that avoids noise?

Strong approach:

  • Alert on symptoms, not raw metrics

  • Use SLO-based thresholds

  • Include actionable detail in alerts

  • Use structured logs and distributed tracing

  • Document runbooks for common issues

  • Regularly review and prune noisy alerts

Deep-dive examples that interviewers love:

  • Migrating from manual dashboards to SLO-based alerting

  • Reducing alert fatigue through silence windows and deduplication

  • Adding tracing that helped debug latency spikes

  • Running blameless post-incident reviews with clear follow-up actions

Other must-know topics:

  • Prometheus metrics best practices (RED/USE patterns)

  • Grafana dashboards for performance analysis

  • OpenTelemetry for unified tracing

  • Error budget policies and how they influence deployment cadence

Real-world DevOps troubleshooting questions

These evaluate how you think—your calmness, clarity, and structure.

Common scenarios:

  • "CPU on this node is 100%. What do you check first?" (Check per-pod usage, runaway processes, node logs)

  • "A deployment succeeded but the service is returning 500s." (Check readiness probes, logs, config changes)

  • "Your pipeline slowed down by 5× today." (Check worker queue congestion, external dependencies, caching)

  • "Traffic doubled overnight and pods won't scale." (Check HPA metrics, cluster autoscaler events, resource quotas)

  • "A pod works locally but fails in the cluster." (Check environment parity, DNS, networking policies)

Tip: Interviewers care more about your reasoning process than your final answer..

Scripting and automation challenges (Bash/Python)

These tests are short, practical, and reflect real tasks you’ll automate on the job.

Common scripting tasks:

  • Find the top 10 largest files in a directory

  • Parse logs and extract error counts

  • Write a script that checks service health and restarts on failure

  • Automate S3 backups with versioning

  • Write a Python script that verifies IAM permissions

  • Build a CLI tool that validates Kubernetes YAML

What interviewers look for:

  • Readability

  • Clear variable naming

  • Use of functions instead of duplicated logic

  • Error handling

  • Comments that explain intent.

What hiring managers are actually evaluating

What they ask What they’re really assessing
"Explain your CI/CD process" Can you design reliable, secure, and scalable delivery pipelines?
"How would you deploy this service?" Do you understand cloud architecture, tradeoffs, and reliability?
"Tell me about difficult incidents you've handled" Can you debug calmly, communicate clearly, and follow structured reasoning?
"How do you optimise Kubernetes costs?" Are you pragmatic about production, resource usage, and scaling?
"Here’s a YAML configuration issue — how would you approach debugging it?" Can you troubleshoot quickly, safely, and methodically under pressure?
"What monitoring would you set up for a new service?" Do you think like an SRE about reliability, SLOs, and observability?

What to focus on based on seniority

Junior DevOps engineers 

  • Linux basics

  • Git fundamentals

  • CI/CD basics

  • Containers (simple Dockerfiles)

  • Cloud fundamentals

  • Basic Terraform

  • Logging and metrics basics

Tip: Focus on understanding fundamentals deeply. Interviewers don’t expect mastery, but they want to see that you can learn fast, ask good questions, and automate small tasks confidently. Show curiosity and eagerness to automate.

Mid-level DevOps engineers 

  • Kubernetes fundamentals

  • CI/CD security and optimisation

  • Terraform modules and best practices

  • Cloud networking (ALB, NLB, routing)

  • Incident response stories

  • Prometheus/Grafana

  • Autoscaling strategies

Tip: Bring specific examples of problems you’ve solved—slow pipelines, failing deployments, scaling bottlenecks, broken infrastructure. Mid-level interviews reward real stories over theory.

Senior DevOps engineers 

  • Cloud architecture and multi-region design

  • Kubernetes internals

  • GitOps (ArgoCD, Flux)

  • SRE principles

  • Cost optimisation

  • Advanced Terraform

  • Complex incident leadership

Tip: Senior interviews focus on tradeoffs, communication, and system-wide thinking. Explain why you made architectural decisions, how you prevented issues, and how you improved reliability across teams.

DevOps culture and behavioural interview questions

Strong DevOps engineers aren’t evaluated only on technical skills, they’re assessed on how they communicate, collaborate, make decisions under pressure, and contribute to a healthy engineering culture.

DevOps is fundamentally about people, processes, and shared responsibility, so interviewers often ask behavioural questions to understand how you operate in real-world environments.

Common behavioural DevOps interview questions (and what they assess)

"Tell me about a time you fixed a broken process."
What they’re assessing: whether you take initiative, reduce friction, and improve workflows rather than accepting dysfunction.

Example answer:
"At my last company, deployments required manual approvals from three teams, which often delayed releases. I mapped out the workflow, identified what could be automated, and worked with engineering managers to implement automated checks and streamlined approvals. This reduced deploy time from hours to under 20 minutes and gave teams more confidence in shipping."

"Describe a difficult production incident you were involved in."
What they’re assessing: calmness under pressure, communication, root-cause thinking, and your ability to learn from failure.

Example answer:
"We experienced a major outage caused by a misconfigured Kubernetes ingress. During the incident, I coordinated updates in Slack, rolled back the change, and added temporary rate limiting to stabilise traffic. Afterward, I led a blameless postmortem that resulted in better config validation and automated canary checks to prevent similar issues."

"How do you handle disagreements with developers or SREs?"
What they’re assessing: collaboration, empathy, and ability to influence without creating friction.

Example answer:
"A developer wanted to disable a failing test to speed up delivery. Instead of blocking the change outright, I asked about the impact of the test and we realised it had caught three production issues in the past quarter. We agreed to temporarily quarantine the flaky test while we fixed it. This kept reliability intact without slowing delivery."

"Give an example of when you automated something that saved your team time."
What they’re assessing: your DevOps mindset — eliminating toil and creating leverage.

Example answer:
"Our team manually rotated logs and archived them weekly. I automated the process using S3 lifecycle rules and a small Lambda function. This saved about 4 hours a week across the team and eliminated a recurring source of human error."

"Describe a time you had to balance speed vs reliability."
What they’re assessing: judgment, pragmatism, and how you evaluate risk.

Example answer:
"We had a critical feature deadline, but our integration tests were unstable. Instead of skipping them entirely, I proposed running a reduced suite focused on the highest-risk paths and enabling canary deployment with automatic rollback. This allowed us to ship on time without compromising reliability."

Tips for answering behavioural DevOps questions

  • Prepare 3–4 stories that demonstrate ownership, collaboration, and problem-solving.

  • Use a simple structure (Situation → Action → Result → Learning).

  • Show how you communicate during incidents, not just how you fix things.

  • Speak honestly about mistakes and what you learned; interviewers value growth mindset.

  • Highlight cross-team work.

Conclusion

DevOps interviews in 2025 aren't just about tools. They're about building reliable systems, thinking clearly under pressure, and automating everything that slows teams down.

Next steps:

  • Practise explaining architecture diagrams

  • Build a mini project with Terraform + K8s

  • Run mock interviews with another engineer

  • Keep track of weak spots and revisit them

You've got this.

DevOps interview FAQ

What are the most commonly asked DevOps interview questions in 2025?
Expect topics such as CI/CD pipelines, Kubernetes troubleshooting, Terraform, cloud architecture, observability, and Linux fundamentals.

How should I prepare for a DevOps technical interview?
Build small end-to-end projects: IaC + Docker + Kubernetes + CI/CD. Practise troubleshooting simulations.

Do I need to know Kubernetes for DevOps roles?
Yes for most cloud-native companies. You should understand deployments, probes, logs, networking basics, and debugging.

What scripting skills are required?
Comfort with Bash is essential. Python is increasingly common for automation and cloud tooling.

What cloud concepts should I revise?
VPC design, IAM, load balancing, autoscaling, storage options, cost optimisation, and backup strategies.

How important is Terraform in DevOps interviews?
Very. It's the default IaC tool for many teams and appears frequently in mid and senior interviews.

What troubleshooting questions should I expect in a DevOps interview?
Expect issues with crashing pods, failing health checks, pipeline slowdowns, scaling issues, and permissions errors.

How do I stand out in a DevOps interview?
Use real examples: migrations you led, outages you stabilised, costs you reduced, or pipelines you improved.