Intermediate everything in DevOps & Cloud, page 11
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.
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 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.
Deployment versus StatefulSet
Deployments suit interchangeable stateless replicas, StatefulSets give stable identities, ordered rollout, and per-Pod persistent storage for stateful systems.
The Kubernetes reconciliation loop
A controller continuously observes actual state, compares to desired state in the spec, and acts to close the gap, level-triggered not edge-triggered.
etcd as the cluster source of truth
Etcd is the consistent key-value store holding all cluster state, accessed only via the apiserver, and uses Raft needing a quorum.
What happens after kubectl apply
Apiserver validates and persists to etcd, scheduler binds the Pod to a Node, kubelet pulls the image and starts the container via the runtime, status flows back.
Manifest lists and multi-arch images
A manifest list maps platform descriptors to per-arch image manifests, the client picks by os and architecture, and pulls only that variant.
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.
We are hiring for this. Every open role lists the topics its interview covers, so you can prepare for the real thing rather than guessing.
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