Interview questions in DevOps & Cloud, page 10
Create a Deployment with 3 replicas via kubectl
Kubectl create deployment webapp --image=my-app:1.0, then kubectl scale to 3 replicas, or use --replicas if supported.
What is IaC and its CI/CD benefits over manual provisioning?
Cover descriptive models, idempotency, and on-demand environments for repeatable CI/CD.
Symptom-based versus cause-based alerting
Symptom alerts fire on user impact like high error rate or latency; cause alerts fire on internal conditions like high CPU. Page on symptoms, treat causes as diagnostic.
How does caching reduce database load?
Cache-aside reads, RAM-speed lookups, TTL plus invalidation.
Debugging a Pod in CrashLoopBackOff
Kubectl describe pod for events, restarts, and last state; kubectl logs (with --previous) for the crashed container's output.
Explain the difference between declarative and imperative IaC.
Contrast Terraform with Bash or Ansible; note drift detection, idempotency, and state trade-offs.
First steps on a p99 latency page
Confirm scope and blast radius, check recent changes and deploys, then look at dependencies and resource saturation.
RDS Multi-AZ versus Read Replicas
Multi-AZ is a synchronous standby for failover, replicas are async for read scaling, combine both when needed.
How a Deployment rolling update works
New image creates a new ReplicaSet; Deployment scales it up while scaling the old one down per maxSurge/maxUnavailable; old ReplicaSet is retained at zero for rollback.
Describe the Terraform workflow from code to live
This tests Terraform workflows beyond local commands. A strong answer covers: version-controlled code, terraform plan for speculative validation, then terraform apply via remote runs with policies. Red flag: only local apply without reviews or remote state.
Fixing a noisy non-actionable alert
Review the data to see if it is ever actionable, then tune threshold or duration, re-target at user-facing symptoms, or delete it.
Strong versus eventual consistency in NoSQL
Strong reads see the latest write at higher latency and cost, eventual reads may be stale but are cheaper and faster, match the choice to stakes.
Rolling back a bad Deployment
Kubectl rollout undo deployment/NAME reverts to the prior revision by scaling the old ReplicaSet back up and the bad one down.
How do you manage secrets within IaC configurations?
This tests secret injection and the security-complexity tradeoff in IaC. A strong answer contrasts a cloud secret manager with encrypted files or env vars, covering rotation and blast radius. A red flag is plaintext secrets in Git or state files.
SLO-based alerting and error budgets
Define SLI/SLO, derive an error budget, alert on how fast you burn it using multi-window multi-burn-rate rules so fast burns page and slow burns ticket.
Data warehouse versus OLTP database
Warehouses use columnar storage for analytical scans, OLTP uses row storage for fast transactions, each fits a different workload.
Liveness vs readiness probes
Liveness restarts a stuck container; readiness gates traffic by controlling Service endpoint membership. Readiness-only fits an app that pauses to reload a large cache but is still healthy.
Explain Terraform state, why managing it is critical, and team best practices
Tests if you know state maps config to real resources and tracks metadata. Strong answers cover remote backends with locking and encryption, never Git. Red flag: local state or ignoring that state files contain secrets.
Anatomy of an effective runbook
Alert meaning and impact, diagnostic steps with dashboard and query links, concrete remediation with rollback, and escalation contacts.
Add a second access pattern to a key-value store
Add a global secondary index on EmailAddress, weighing extra storage, write amplification, and eventual consistency.
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