Kubernetes Simulator

A Go CLI and web GUI for practicing Certified Kubernetes Administrator (CKA) exam scenarios against a real or simulated cluster.

Inject faults, repair workloads, get graded — no cloud account required.

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Features

• 32 mission labs covering pods, deployments, RBAC, networking, storage, scheduling, and more
• Inject ? Repair ? Grade loop that mirrors real CKA exam tasks
• Fake-client mode — runs entirely offline using client-go/fake (no cluster needed)
• Live mode — grades against a real kubeconfig-connected cluster
• Web GUI with simulated kubectl terminal, step-by-step tutorials, visual dashboard, and free-play sandbox
• Self-test command for quick validation without any external dependencies

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Quick Start

# Build the CLI
go build -o cka-sim ./cmd/cka-sim

# Run the built-in self-test (no cluster required)
./cka-sim self-test

# Or inject a fault and grade the repair
./cka-sim inject --namespace default --pod nginx-pod --broken-image nginx:no-such-tag
# ... fix the pod ...
./cka-sim grade --namespace default --pod nginx-pod --image nginx:1.25

Web GUI

cd web
npm install
npm run dev

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Architecture

cmd/cka-sim/         CLI entrypoint
internal/
  grader/            Grading logic (checks pod state, image, readiness)
  injector/          Fault injection (broken images, misconfigs)
  scenarios/         Scenario definitions
  selftest/          End-to-end fake-client test flow
web/                 React + TypeScript learning GUI (Vite)

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Mission Labs (32)

Pod image repair · Node scheduling clinic · PV binding workshop · RBAC access mission · Deployment rollout recovery · Readiness probe repair · ConfigMap key correction · Secret environment repair · Service selector mismatch · Ingress backend correction · CrashLoopBackOff arguments · Taint and toleration match · Namespace context cleanup · Job completion repair · CronJob schedule correction · NetworkPolicy access restore · Resource request tuning · ServiceAccount binding repair · DaemonSet image repair · StatefulSet service wiring · Label selector repair · Cross-namespace service lookup · Finalizer troubleshooting · EndpointSlice readiness review · Pod DNS policy fix · Pod Security Baseline review · ServiceAccount token mount control · kubectl client verification · kind cluster bootstrap · minikube startup verification · Hello Minikube deployment · kubeadm learning path choice

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Prerequisites

• Go 1.21+
• Node.js 18+ (for the web GUI)
• kubectl configured (live mode only)

Test

go test ./...

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References

• Kubernetes API overview
• client-go
• CKA Exam Curriculum

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License

MIT