Interview questions in DevOps & Cloud, page 11
Sharing ephemeral cache between containers in a Pod
Use an emptyDir volume defined in the Pod spec and mounted into each container at the cache path; it is created with the Pod and deleted when the Pod is removed.
Design a CI/CD pipeline for ephemeral feature branch environments
This tests dynamic infrastructure lifecycle modeling in CI/CD. A strong answer covers branch-triggered provisioning, dynamic naming, automatic cleanup via stop jobs, and cost controls. Red flag: proposing manual teardown or static environments per branch.
Designing an escalation policy
Define timeout-based escalation tiers, multiple notification channels, secondary and management layers, coverage across time zones, and severity-based routing.
Design a global low-latency database
A distributed store with replicas near users, a tuned consistency level, accepting lag, conflicts, and cross-region cost.
Tuning maxSurge and maxUnavailable
MaxSurge allows Pods above desired; maxUnavailable allows Pods below desired during update. For zero downtime and speed, set maxUnavailable 0 and maxSurge high (e.g. 100%).
Define configuration drift in IaC. How do you detect and remediate it?
This tests state divergence between declared and live infrastructure. A strong answer defines drift as deviation from the IaC source of truth, proposes automated scanning for detection, and recommends reconciliation or redeployment.
Measuring on-call health quantitatively
Track pages per shift especially off-hours, actionability rate, time-to-resolve, and load distribution; use trends to prioritize reliability work and protect against burnout.
CAP theorem and real database tradeoffs
During a partition you pick consistency or availability, CP systems reject requests, AP systems stay available but stale.
Stalled rollouts and progressDeadlineSeconds
With maxUnavailable respected, the rollout pauses partway and old Pods keep serving; progressDeadlineSeconds marks the Deployment as failed after no progress for that window.
Infrastructure apply fails midway. What is the state and your immediate steps?
This tests partial-state reasoning and safe recovery. A strong answer halts automation, inspects state for blast radius, then chooses idempotent roll-forward or rollback with canary validation.
Catching rare intermittent failures
Add high-cardinality traces and structured logs with exemplars, use tail-based sampling to keep failing traces, and alert on SLO burn rather than coarse averages.
The cloud shared responsibility model
The provider secures the cloud (hardware, OS, runtime), you secure what runs in it (code, data, config, access).
Spreading Pods one-per-node for availability
Use required podAntiAffinity with topologyKey kubernetes.io/hostname matching the Deployment's own pod labels, so the scheduler refuses to co-locate two Pods on a node.
Compare Terraform and Ansible: when to use each and both together
This tests whether you distinguish provisioning from config management. Strong answers define Terraform for immutable infra and Ansible for mutable state, contrast day 0 versus day 1-2 work, and cover Terraform for VMs and Ansible for setup.
Alert silencing versus alert inhibition
Silencing mutes by matcher for a window, inhibition suppresses lower alerts when a higher one fires, dependency-aware.
Why not store uploads on local PaaS disk?
PaaS instances are ephemeral and unshared, so local files vanish on restart and are invisible to peers; store uploads in object storage.
Why Kubernetes Services exist
Pod IPs are ephemeral and change on reschedule; a Service gives a stable virtual IP and DNS name plus load balancing across healthy Pods via label selectors.
How do you manage environment-specific connection strings and why is hardcoding bad?
Tests config separation and secrets hygiene. Outline: inject via environment variables or a secret store, keep per-environment configs credential-free, and prefer managed identities.
Triaging a 5xx error spike
Confirm impact and scope, declare and assign roles, check recent changes, stop the bleeding before root cause.
Deploying to Heroku via Git
Push to the remote, a buildpack detects the language, builds a slug, and runs the Procfile process.
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