Intermediate everything in DevOps & Cloud, page 12
Three techniques to shrink a Docker image
Multi-stage builds to drop build tooling, smaller base images like slim or distroless, and fewer or cleaner layers plus dockerignore.
Debugging ImagePullBackOff on a private registry
ImagePullSecrets reference a dockerconfigjson Secret on the pod or service account, kubelet uses it to authenticate, and you inspect events to isolate auth versus name versus network errors.
What is a build artifact? Give Java, JS, and C++ examples.
Define artifacts as compiled outputs; list JAR/WAR for Java, webpack bundle for JS, and binary/.so for C++; note immutability.
How do you speed up slow integration tests without compromising quality?
Tests your ability to optimize CI/CD pipelines while preserving coverage. A strong answer covers parallel execution, Test Impact Analysis, ephemeral containers, and test data as code. Red flag: proposing to delete tests or disable integration stage entirely.
Automate a canary release with a 1% 5xx error threshold
This tests wiring an SLO into an automated canary loop. A strong answer covers traffic splitting via a mesh or ingress, an analysis query to Prometheus for 5xx rate, and auto-promote or abort logic.
Describe the difference between a Deployment and a StatefulSet
Tests stateful pod identity versus stateless scaling. Outline: contrast Deployments' interchangeable replicas with StatefulSets' stable hostnames, per-pod PVCs, and ordered rollout; give a database example.
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.
What does shift left mean in CI/CD, and give two concrete examples?
Your grasp of moving verification earlier to reduce cost and risk. Define shift left as earlier-stage testing; cite two concrete examples like pre-commit unit tests and PR-level SAST scans. Never call it "more testing" instead of earlier feedback.
Continuous Delivery vs Continuous Deployment: key differences and choosing between them
Tests the human-gate distinction: Delivery readies artifacts but requires manual approval; Deployment pushes automatically. Strong answers cite compliance, blast radius, and maturity. Red flag: conflating terms or claiming full automation fits every app.
GitLab Pipeline Configuration Hierarchy
GitLab pipeline settings stack like access-control layers. Project visibility, pipeline toggles, and role permissions interact to determine who sees logs, artifacts, or can cancel jobs.
SLOs Tied to User Journeys, Not APIs
A user-journey SLO measures the full flow a person experiences, not one microservice's health. If checkout is 99.9% up but payments fail, the metric lied. Teams drown in green per-service dashboards while users are furious.
DevOps Is Culture, SRE Is Engineering
DevOps is a cultural philosophy for fast, safe delivery; SRE is the engineering discipline that implements it with error budgets and SLOs. They are complementary, not rival job titles. The footgun is hiring SREs and declaring DevOps done.
AWS Fault Injection Simulator
AWS Fault Injection Simulator is a controlled chaos button: it breaks resources on purpose to prove your failover works before real disasters. Run it before peak traffic to validate auto-healing.
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.
Describe the relationship between containerd and runc in starting a container.
Tests the OCI runtime split and lifecycle ownership. A great answer states containerd handles image pull, storage, and API lifecycle, then invokes runC to spawn the isolated process.
How do containers enforce CPU and memory limits via cgroups?
Cover CPU CFS quota and shares, memory limits and OOM, and runtime cgroup config.
Name three Linux namespaces and explain what each one isolates.
Name three of PID, Network, Mount, UTS, IPC, User, Cgroup, Time; say what each hides; cite CLONE_NEW* or /proc/pid/ns.
Docker Content Trust: Signed Image Verification
Docker Content Trust is a cryptographic tamper-evident seal for image tags. It lets you verify who published an image before pulling from any registry. The footgun is that without DOCKER_CONTENT_TRUST=1, unsigned tags pull silently with no warning.
Container Images Are Stacked Deltas
Images stack read-only layers like transparent sheets, one per Dockerfile step, topped by a thin writable layer. This enables cache reuse and fast pulls. The footgun: removing a file in a later layer hides but does not delete it; those bytes still ship.
OLM: Kubernetes' App Store for Operators
OLM is the app store for Kubernetes Operators: it installs, updates, and resolves dependencies declaratively. Use it when managing third-party or custom Operators across clusters.
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