These are the questions you should expect during the basic core test of DevOps principles in a DevOps training course. It's not enough to memorize definitions; the key is demonstrating how these principles are applied in real-world scenarios. A DevOps training course will help you understand and implement these concepts effectively, preparing you for real-world challenges.

1. What is DevOps, and why do we need it?

DevOps is a set of practices that unites development and operations teams to improve the flow of software delivery.
The objective? Speedier releases, greater quality, and feedback loops that are more frequent.
It is practically closing the gap of writing and running the code, not only about tools but also culture, automation, and shared ownership.
From a previous position, we can now say we have managed to integrate DevOps into quickly deploying machine learning models that have drastically reduced the deployment time while enhancing deployment stability.

2. How does DevOps differ from the old school IT?

The traditional IT environment divides the responsibilities – the code is written by developers, and the operation deploys and maintains said code. DevOps is the integration of these roles, with a strong emphasis on shared responsibilities as well as intense automation.
In DevOps, for example:

• Scripts for deployment are written by developers themselves.

• Operations would roll in earlier in the chain.

• Releases occur continuously and not in periodic, massive bursts-of-the-quarter releases.

• DevOps removes the wall between the two dissimilar departments that only communicate with each other through tickets.

3. What are the basic principles of DevOps?

The key principles of DevOps include:

• Collaboration: Breaking down silos between dev, ops, QA, and security.

• Automation: Testing, deployment, and monitoring are automated.

• CI and CD (Continuous Integration and Delivery): They ship smaller, safer changes more frequently.

• Monitoring and Feedback: Always learning and adapting.

• These principles are the essence of DevOps, the touchstone by which one defines whether a team truly practices DevOps or simply uses its tools while clinging to old habits.

4. Which most popular DevOps tools? Describe their uses.

   Here are some key tools in DevOps:

• Git: Code version control.

• Jenkins/GitLab CI: CI/CD pipelines.

• Docker: Containerization.

• Kubernetes: Container orchestration.

• ArgoCD: GitOps for continuous delivery.

• Terraform: Infrastructure as code (IaC).

• Prometheus + Grafana: Monitoring and data visualization.

5. What is CI/CD?

CI/CD stands for Continuous Integration and Continuous Delivery (or Deployment).
The backbone of DevOps automation reads as follows:

• CI: Developers keep merging code into a shared repository from time to time, which, upon being updated, initiates builds and tests.

• CD: In case all tests pass, the new version is automatically pushed into production (or staging).

• CI/CD will minimize human errors while ensuring predictability during deployments.

• For example, when developing our model deployments, we have unit tests triggered for every push to a feature branch, while merging into the main branch would trigger the building of a new Docker image and deployment into our Kubernetes clusters.

6. Benefits of Automation in DevOps

Automate tasks that are redundant, increase dependability, and set up teams to scale in their operations.

• Fast feedback loop

• Fewer mistakes in deployment

• More consistent and repeatable environments

• Less drama with "It works on my machine"
  As a rule of thumb: repeat it, then automate it.

7. What is Infrastructure as Code (IaC)?

IaC means managing infrastructure using code and not manual configuration of systems on cloud consoles.
Using Terraform or CloudFormation, you will then define infrastructure in files whose characteristics are:

• Reproducible

• Version-controlled

• Easy to audit

• IaC provisions such environments in a few minutes, not after days of configuration.

8. How is Git and version control related to DevOps?

Version control is not just meant for code but also for many other things that are usually done in DevOps. In a DevOps environment, versioning includes:

• Code

• Infrastructure

• Documentation

• Collaboration is made easier, rollback options are available, and everything is traceable with Git. Tools like GitHub Actions or GitLab CI/CD easily get along with Git workflows, and thus, tasks are automated.

9. Why do we monitor and log in DevOps?

• Monitoring and logging are generally important in troubleshooting and improving systems.

• Monitoring: Real-time insight providing the following (CPU usage, uptime, and error rates).

• Logging: Records earlier events (such as error messages, stack traces). Together, they bring in early detection, performance tracking, and change impact analysis.

10. Can you give an example of a basic CI/CD pipeline?

An example of a typical CI/CD pipeline would be:

• A developer pushes code to the master branch.

• The pipeline runs the unit tests and static analysis.

• If successful, the next step builds the image and packages it into Docker.

• Push to the registry.

• Deploy to a staging environment using Kubernetes.

• If everything goes well, there's a manual approval step before production deployment.

Intermediate DevOps Interview Questions

These are the questions that deep-dive into your technical proficiency as a DevOps engineer in containers, CI/CD, infrastructure automation, and troubleshooting. Be prepared for not just justification of design decisions but also troubleshooting under pressure.

11. What is a deployment strategy? Name a few.

A deployment strategy defines how a software's new versions are released.
Some of the well-known strategies include:

• Blue-green deployment: Two identical environments (blue=current, green=new). Traffic is shifted to green once it’s stable.

• Canary release: Traffic is directed toward a small user group, then gradually expanded.

• Rolling update: Update instances one by one, ensuring no downtime.

• Recreate deployment: Kill the old version completely, then bring up the new one (riskier, with downtime).

12. How do you consider containers and orchestration in DevOps?

Containers (like Docker) package applications with everything they need to run, delivering cross-environment consistency.
These include scaling applications based on resource usage, failovers, and self-healing, networking, and service discovery.

13. How would you perform blue-green deployment?

A simplified version would be:

• Two identical production environments: current blue and new green.

• Deploy the new version into green.

• Test it and validate it.

• After confidence, switch all traffic to green, with blue still available should a fallback become necessary.

14. What distinguishes a rolling update from a canary release?

A rolling update gradually replaces old versions with new ones, ensuring no downtime.
A canary release has its new version rolled out to a small group of users at first to catch any early issues before opening it up to full deployment.

15. What is meant by the security of a CI/CD pipeline?

    For securing the pipeline so that no vulnerabilities can be penetrated:

• Use secrets management tools (e.g., AWS Secrets Manager, HashiCorp Vault).

• Run builds in isolated environments.

• Validate inputs to prevent injection attacks.

• Integrate static and dynamic analysis tools.

• Always use signed containers and verify their sources.

Advanced DevOps Interview Questions

These questions test your knowledge of system architecture complexities and scale, security, and leadership. Trade-offs and design decisions at scale will be discussed.

21. What does GitOps mean, and how is it different from DevOps?

• GitOps is a practice within DevOps that uses Git as the single source of truth for infrastructure and applications.

• Every change is done through pull requests to a Git repository, and technologies like ArgoCD or Flux will monitor those changes and push them up into the cluster.

• GitOps brings all of the versioned, auditable, and quick rollback benefits to infrastructure management.

22. Can you explain policy-as-code in simple terms and with examples?

Policies-as-code is writing the operational, security, and compliance rules in code, so that automated enforcement is easily achievable.
For example:

• Block all unnecessary public services (operations) exposed by service deployments using OPA (Open Policy Agent).

• Enforce that ownership tags are on all infrastructure resources in Terraform.

• No CI/CD deployments to production without some approvals.

23. How would you design a scalable CI/CD system?

Scalable CI/CD systems are flexible, modularized, and speed-optimized. It should include the following:

• Build the pipeline, decoupling all the stages like build, test, and deploy.

• Running tasks in parallel so that the bottleneck can be minimized.

• Dynamic runners on Kubernetes that scale resources when required.

• Cache dependencies so built images don't have to access the internet all the time.

24. What will happen if an incident occurs, and how would you respond?

Principles:

• Stay calm

• Diagnose fast (Network issue? App level? Infra?)

• Communicate clearly

• Document everything

• Run a post-mortem (identify root cause and learn)

• Never blame people — focus on systems, processes, and improvements.

25. Which tools do you use for microservices observability?

What to observe:

• Logging: Centralized, structured, searchable (e.g., ELK, Loki)

• Metrics: Prometheus (time series) + dashboards (e.g., Grafana)

• Tracing: Distributed tracing tools like Jaeger or Open Telemetry

• Put in correlation IDs to link requests across services

26. Optimize slow pipelines

Steps:

• Measure first using pipeline metrics and step timings.

• Smartly cache: dependencies, Docker layers, test results

• Split tests: parallelize test suites by type or module

• Use pre-commit hooks to catch early errors.

• Skip unnecessary steps: use conditional logic (only build Docker if code changed in respective code location)

• Faster hardware alone doesn’t fix issues; focus on efficiency.

27. How does compliance come into your DevOps workflow?

Compliance integration:

• Version everything (code, infra, and policies)

• Git, CI/CD logs, monitoring tools, and access trails

• Automated compliance checks (CIS checks, security scanners)

• RBAC and least-access controls

• Secrets management with rotation policies

28. Tell us about service meshes in DevOps

Key points:

• Controls service-to-service communication

• Features:

  • Traffic control (retries, timeouts, routing)

  • Security (mTLS between services)

  • Observability (per-service telemetry)

• Managed through sidecar proxies

• Examples: Istio, Linkerd

29. Deployed zero-downtime architectures

Strategies:

• Traffic shifting: blue-green or canary deployments

• Database migrations are backward compatible.le

• Load balancer health checks before adding new instances

• Graceful shutdowns to let in-flight requests complete

30. What is chaos engineering, and have you used it?

Definition:

• Introduce failures purposely to test system resilience.

Tools:

• Gremlin

• Chaos Monkey

• Litmus

Scenarios:

• Killing random pods

• Simulating network latency

• Dropping DB connections

Note: Netflix uses chaos engineering to test system stability