Case Studies & Practical Application Flashcards

A gaming company's leaderboard API on GKE handles 10k RPS normally but fails during tournament events with 100k RPS. The team already uses horizontal pod autoscaling. What additional change addresses the traffic spike?

Answer: Pre-scale the deployment before the event and configure cluster autoscaler with surge nodes

HPA reacts to existing load; pre-scaling ensures capacity is ready before the event, and cluster autoscaler surge nodes prevent node provisioning delays from limiting pod scheduling.

An enterprise runs Terraform to manage 500 AWS resources. A junior engineer accidentally runs `terraform destroy` on a production workspace. Which preventive control would have stopped this?

Answer: Using Terraform Cloud with Sentinel policies that block destroy plans in the production workspace

Sentinel policies in Terraform Cloud can enforce rules like blocking destroy operations in designated workspaces before a plan is applied.

A company's Azure AKS cluster costs are 60% higher than budgeted. Analysis shows average node CPU utilization at 15% and memory at 20%. What is the most effective cost reduction strategy?

Answer: Right-size pods with VPA recommendations and enable cluster autoscaler to scale down idle nodes

Low utilization means pods are over-provisioned; VPA right-sizing packs more pods per node, and cluster autoscaler removes underutilized nodes, directly reducing the node count.

A data engineering team ingests 1TB of JSON logs daily into AWS S3, then queries them with Athena. Queries scan the full 1TB each time, costing $5/query. What single change reduces query cost most?

Answer: Convert logs to Parquet format with Snappy compression and partition by date

Parquet's columnar format allows Athena to scan only required columns, and date partitioning prunes irrelevant partitions; together they can reduce data scanned by 95%+.

A SaaS platform on GCP needs to send transactional emails but Gmail flags them as spam. SPF is configured. What additional DNS/mail configurations should the engineer verify?

Answer: Configure DKIM signing and a DMARC policy for the sending domain

DKIM cryptographically signs emails so receiving servers can verify authenticity, and DMARC tells receivers how to handle failures; together they significantly reduce spam classification.

A multi-region AWS deployment uses Route 53 latency-based routing. Users in Europe report that they are sometimes routed to us-east-1 instead of eu-west-1. What is the most likely cause?

Answer: The eu-west-1 health check is failing, causing Route 53 to failover to us-east-1

Route 53 latency routing respects health checks; if the eu-west-1 endpoint health check fails, Route 53 routes users to the next healthy region regardless of latency.

A company migrates on-premises VMs to Azure using Azure Migrate. Post-migration, the application team reports that internal service discovery no longer works. What is the most likely root cause?

Answer: The migrated VMs use hardcoded IP addresses that differ in the Azure VNet

On-premises services often use static IPs for internal communication; after migration to Azure, VMs receive new private IPs, breaking hardcoded references unless DNS or configuration is updated.