Advanced Questions¶
How to use these interview questions
🧠 Read each question carefully.
Try answering it yourself before expanding the answer to compare with the ideal response.
Level: Advanced
🔴 Complex Scenarios & Architecture.
Tackle high-level design, production-grade scaling, security, and advanced internals.
1. How can you securely access a private RDS database from a Lambda function running inside a VPC without hardcoding credentials?
Use IAM Database Authentication.
This allows you to use an IAM role attached to the Lambda function to authenticate with the database, generating a temporary auth token. This removes the need to store static passwords in Secrets Manager or code.
2. What is "Cross-Account Access" in the context of CodePipeline?
Setting up a pipeline in one account (e.g., Tools/Shared Services) that deploys resources to another account (e.g., Prod) using AssumeRole.
✔ Benefit: Centralized deployment model where a secured "Tools" account orchestrates changes into target environments.
3. You need to debug a high-latency issue in a microservices architecture. Which tool provides end-to-end tracing?
AWS X-Ray.
X-Ray visualizes the service map and provides traces that show the latency of each component (Lambda, DynamoDB, API Gateway) in the request path.
4. How do you implement "Policy as Code" to prevent developers from creating public S3 buckets?
Use AWS Service Control Policies (SCPs) at the Organization root level.
SCPs provide a guardrail that overrides any local permission (even AdministratorAccess), effectively blocking prohibited actions (like s3:PutBucketPublicAccessBlock) organization-wide.
5. What is a "Dead Letter Queue" (DLQ) used for in AWS Lambda?
To capture events that failed processing after all retry attempts.
For asynchronous invocations, Lambda sends failed events to a configured DLQ (SQS or SNS) for later analysis and debugging.
6. In a disaster recovery scenario, what is "Pilot Light"?
A minimal version of the environment is always running in the cloud (e.g., core DB replication), but compute is off or minimal until needed.
✔ Tradoff: Faster RTO than "Backup and Restore" but cheaper than "Warm Standby".
7. How do you handle "Secret Rotation" automatically for an RDS database password?
Configure AWS Secrets Manager to rotate the secret using a built-in Lambda function.
It automatically updates the password in the database and the secret value in Secrets Manager on a schedule.
8. What happens to a Spot Instance if the Spot price exceeds your bid price?
AWS terminates (or stops/hibernates) the instance with a 2-minute warning.
✔ Design consideration: Your application must handle graceful shutdown within this 2-minute window.
9. How do you implement a "Linear" deployment configuration in CodeDeploy?
Use Linear10PercentEvery10Minutes (or similar).
It deploys traffic to 10% of the fleet, waits 10 minutes, checks health, then proceeds to the next 10% until 100%. This provides a steady, controlled rollout.
10. What is the "Warm Pool" feature in Auto Scaling?
A pool of pre-initialized EC2 instances (in a stopped state) ready to be placed in service instantly.
✔ Benefit: Reduces scale-out latency for applications with long boot times.
11. How do you secure the build artifacts produced by CodeBuild that are stored in S3?
Enable Server-Side Encryption (KMS) on the S3 bucket and restrict access using Bucket Policies.
12. Which method allows you to deploy Kubernetes manifests to EKS automatically whenever code is committed to Git?
Use a GitOps operator like ArgoCD or Flux running inside the cluster.
The "Pull" model (GitOps) ensures state reconciliation: if the cluster drifts, the operator pulls the correct config from Git and reapplies it.
13. You receive a "LimitExceeded" error for Lambda concurrent executions. How do you fix this for a critical function?
Configure Reserved Concurrency.
This guarantees a set amount of concurrency for that specific function, ensuring it isn't starved by other noisy functions in the account.
14. How can you ensure that your ECS Tasks always have the latest security patches for the underlying OS?
Use AWS Fargate.
Fargate is serverless; the responsibility of OS patching and management shifts entirely to AWS. You only manage the container image.
15. What are "VPC Endpoint Policies"?
IAM resource policies attached to the VPC Endpoint (Gateway or Interface).
✔ Use Case: Restrict access so that users in the VPC can only access specific S3 buckets (e.g., company-internal) and not their personal S3 buckets.
16. How do you automate the cleanup of old AMI snapshots to save costs?
Use Amazon Data Lifecycle Manager (DLM).
DLM provides a simple, automated way to create and delete EBS snapshots based on retention schedules (e.g., delete snapshots older than 30 days).
17. Which advanced deployment technique releases version B to a subset of users based on HTTP headers?
A/B Testing (or Targeted Canary).
Using ALB weighted routing with conditions or feature flags, you can target specific user segments (e.g., user-type=beta) rather than just a random percentage.
18. What is the "EKS Anywhere" service?
A deployment option to create and operate Kubernetes clusters on your own on-premises infrastructure (VMware vSphere, bare metal).
It provides consistent tooling with cloud-based EKS.
19. How do you enforce that all CloudFormation stacks must include a "CostCenter" tag?
Use Tag Policies (AWS Organizations) or AWS Service Catalog.
Tag Policies allow you to standardize tags across resources, effectively blocking the creation of untagged resources if configured for enforcement.
20. What is "Split-Tunneling" in the context of Client VPN?
Routing only VPC-destined traffic through the VPN tunnel, while letting internet traffic (e.g., YouTube, Zoom) go through the user's local ISP.
✔ Benefit: Prevents bottlenecking the corporate VPN bandwidth.
🧪 Ready to test yourself?¶
👉 Take the AWS DevOps Engineer Advanced Quiz
📬 DevopsPilot Weekly — Learn DevOps, Cloud & Gen AI the simple way.
👉 Subscribe here