Interview questions in DevOps & Cloud, page 2
How do you find and eliminate toil systematically?
Inventory and measure toil via time tracking or ticket analysis, prioritize by frequency times cost versus automation effort, automate highest-ROI items, measure success…
When hybrid cloud beats public or private
Give a scenario like regulated data plus bursty compute; keep sensitive data and legacy systems on-prem, run scalable or customer-facing workloads in public cloud.
What is Infrastructure as Code (IaC), and how does it support CI/CD?
This tests if you link declarative definitions to repeatable pipelines. A strong answer covers idempotence, versioned templates, and preventing snowflake environments. A red flag is calling IaC mere scripting without CI/CD integration.
Explain layered filesystems like OverlayFS and their efficiency vs monolithic models
This tests copy-on-write layering and deduplication in container storage. A strong answer covers lowerdir/upperdir/merged mounts, layer reuse across images, and why diff-based distribution beats monolithic blobs.
What makes a blameless postmortem effective?
Cover summary, impact, timeline, root cause, action items; explain blameless means focusing on systemic causes so people report honestly.
What is the OCI and why do its specs matter?
OCI defines vendor-neutral specs for image format and runtime so any compliant tool interoperates; runc implements the runtime spec; this prevents lock-in.
Designing for portability across two clouds
Abstract via containers, Terraform, and open standards; avoid proprietary managed services.
Pipeline is green but lead time grows. Three areas to investigate?
This tests distinguishing pipeline health from delivery flow efficiency. A strong answer targets pre-merge wait states, slow green pipeline stages, and post-merge deployment friction, using time-in-stage metrics.
Risky launch with a near-empty error budget?
Contain blast radius via canary and feature flags, use progressive rollout tied to budget burn, negotiate explicit risk acceptance, add fast rollback.
Trace a container process's syscalls from the host
Find the host PID via docker inspect or ps, then strace -p that PID from the host, since the container shares the host kernel.
Hybrid cloud bursting from a VMware footprint
Evaluate VMware Cloud on AWS, Azure Arc, Outposts; address connectivity, identity, and data gravity.
How does your CI/CD strategy differ between monoliths and microservices?
Contrast monolith unified builds with microservice independent deploys, side-by-side versions, and service gates.
SRE vs traditional ops on a recurring alert?
Traditional ops repeatedly handles the alert manually and scales by adding people; SRE treats it as a bug, automates or eliminates the root cause, and scales sublinearly.
Build, tag, and run a container with port mapping
Docker build -t my-app:1.0 . to build and tag; docker run -d -p 8080:80 my-app:1.0 to run detached with host:container port mapping.
Launching a virtual machine in the cloud
Pick image, instance type, network placement and security, attached storage, and access keys.
Explain blue-green deployment, its prerequisites, and how it reduces deployment risk.
Tests operational maturity for zero-downtime cutover. Great answers: parallel environments, load balancer switching, backward-compatible schemas, externalized state, and instant rollback vs partial in-place failure.
Error budget policy across dependent microservices?
Set per-service SLOs but anchor on user-facing journey SLOs, budget for dependency error via the multiplication of availabilities, attribute downstream-caused failures correctly, and use…
Dockerfile COPY versus ADD
COPY just copies local files; ADD also auto-extracts local tarballs and can fetch remote URLs; prefer COPY for predictability, use ADD for local archive extraction.
What a machine image is and why it matters
An image is a frozen template of OS, software, and config; it makes launches identical and fast.
Difference between git merge and git rebase before a pull request
Rebase rewrites SHAs, duplicating CI builds; merge keeps identity and triggers one build.
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