DevOps Interview Preparation

Diagnose an AWS connectivity failure by tracing a packet path through DNS, routes, gateways, security groups, network ACLs, and VPC Flow Logs.

Use AWS CloudShell and the AWS CLI to create and validate a versioned, encrypted S3 bucket with public access blocked and a least-privilege bucket policy, then remove the resources safely.

Configure CloudFront Origin Access Control for a private S3 origin, verify direct-versus-CloudFront access and cache invalidation, and document cleanup steps.

Build and test an SNS-to-SQS fan-out flow with subscription filtering, an appropriate visibility timeout, retries, and a dead-letter queue, then clean up the resources.

Select among RDS, Aurora, DynamoDB, and ElastiCache for an interview scenario by evaluating consistency, scaling, availability, recovery, and cost requirements.

Complete and explain a provided Jenkins declarative pipeline that builds, tests, scans, archives an artifact, requires approval, and promotes a release between environments.

Diagnose a failed Jenkins pipeline using stage logs, agent state, credential handling, artifact flow, deployment evidence, and rollback options.

Modify and run a starter GitHub Actions workflow on a hosted runner using controlled triggers, dependent jobs, caching, artifacts, scoped permissions, secrets, and an environment gate.

Choose between Jenkins and GitHub Actions for a delivery scenario by comparing hosting, scaling, security, extensibility, and operational overhead.

Refactor a provided Terraform root configuration in a browser editor into a reusable module with typed inputs, outputs, version constraints, and multiple module instances.

Decide when Terraform CLI workspaces are appropriate versus separate root configurations and state backends, and explain the resulting isolation, locking, drift, and recovery trade-offs.

Diagnose Pending, CrashLoopBackOff, ImagePullBackOff, OOMKilled, and failing-probe scenarios from kubectl-style events, logs, and resource status.

Trace and troubleshoot Kubernetes traffic through Ingress, Service, EndpointSlice, DNS, network policy, and target Pods.

Revise a Kubernetes workload manifest to use appropriate probes, resource requests and limits, security context, rollout controls, and a PodDisruptionBudget.

Choose scheduling and scaling controls for a scenario using affinity, taints and tolerations, topology spread, HPA, and cluster autoscaling.

Explain how a service mesh separates control-plane and data-plane responsibilities and determine when its security, observability, and traffic features justify its complexity.

Review Istio Gateway, VirtualService, and DestinationRule resources to implement weighted canary traffic and diagnose routing mistakes.

Write PromQL queries for availability, latency, traffic, error, and saturation signals using labels, rates, aggregation, and histogram quantiles.

Design a Grafana dashboard and actionable alert set for a service using symptoms, thresholds, evaluation windows, and runbook links.

Review and correct an Nginx reverse-proxy and load-balancing configuration covering forwarded headers, timeouts, upstream failover, TLS termination, and safe defaults.

Correlate CloudWatch metrics and logs with CloudTrail audit events to identify an AWS incident's cause and timeline, then explain when Prometheus metrics or New Relic traces would supply missing evidence.

Choose among CloudFront or Fastly at the edge, Nginx at ingress, and Istio or another service mesh for east-west traffic brokering by comparing request location, caching, control, resilience, and cost.

Given a representative production workload, produce and defend an end-to-end AWS platform architecture covering networking, data services, CI/CD, Terraform, Kubernetes, traffic management, observability, security, failure recovery, and cost trade-offs.