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☸️ Kubernetes Cheat Sheet (2025 Edition) – From Beginner to Advanced

Kubernetes is powerful. But with so many moving parts — pods, services, YAMLs, CRDs, controllers — it’s easy to feel lost.

This cheat sheet is your go-to guide to everything Kubernetes — covering basic commands, architecture, YAML templates, security, Helm, GitOps, observability, and more.

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🧠 1. What is Kubernetes?

Kubernetes is an open-source container orchestration system used to deploy, scale, and manage containerized applications automatically.

• Created by Google
• Maintained by CNCF
• Runs everywhere — cloud, edge, or on-prem

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🧱 2. Kubernetes Architecture

Component	Role
Control Plane	Schedules & controls the cluster
Node	Worker machine (VM or physical)
Pod	Smallest unit, wraps 1+ containers
Deployment	Ensures desired state (e.g., 3 pods)
Service	Exposes pods (ClusterIP, NodePort, LoadBalancer)
Ingress	Routes external traffic (domain-based rules)
ConfigMap	Non-sensitive config
Secret	Sensitive credentials (API keys, passwords)
Namespace	Logical grouping (multi-tenant or per environment)

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🔧 3. kubectl Cheat Sheet (Top Commands)

🔍 Basics

kubectl get nodes              # Show cluster nodes
kubectl get pods               # Show all pods
kubectl get svc                # Show services
kubectl get deployments        # Show deployments
kubectl get namespaces         # List namespaces

📦 Pod Management

kubectl logs <pod>             # View logs
kubectl exec -it <pod> -- bash # Shell inside container
kubectl describe pod <pod>    # Details of a pod
kubectl delete pod <pod>      # Delete pod

📂 Apply/Manage YAMLs

kubectl apply -f file.yaml     # Create/update resource
kubectl delete -f file.yaml    # Delete from config
kubectl create -f file.yaml    # Create resource
kubectl diff -f file.yaml      # Show changes before applying

🧪 Debugging & Test

kubectl explain pod            # Show schema
kubectl top pod                # Show CPU/RAM usage
kubectl port-forward svc/myapp 8080:80

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✍️ 4. Essential YAML Templates

✅ Pod

apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - name: nginx
    image: nginx:latest

✅ Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp
        image: myimage:v1

✅ Service

apiVersion: v1
kind: Service
metadata:
  name: myapp-service
spec:
  type: LoadBalancer
  selector:
    app: myapp
  ports:
    - port: 80
      targetPort: 8080

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📦 5. Resource Types Cheat Sheet

Type	Description
Pod	Runs 1+ containers
Deployment	Rolling updates, replica management
StatefulSet	For apps like databases, persistent identity
DaemonSet	Runs 1 pod per node (e.g., logs agent)
Job	One-time tasks
CronJob	Scheduled jobs (like cron)
ConfigMap	Environment configs
Secret	Encrypted data
Service	Expose app
Ingress	HTTP routing with host/path rules
PersistentVolumeClaim (PVC)	Request storage from cluster
HorizontalPodAutoscaler	Scale pods by CPU/memory

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🔐 6. Security Cheat Sheet

Feature	Use
RBAC	Control access (Role + RoleBinding)
Namespaces	Isolate resources logically
Network Policies	Restrict traffic between pods
Pod Security	Enforce seccomp, runAsNonRoot
Secrets	Store passwords, tokens
Admission Controllers	Enforce rules before deploy

RBAC Example:

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: dev
  name: pod-reader
rules:
- apiGroups: [""]
  resources: ["pods"]
  verbs: ["get", "watch", "list"]

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🛠️ 7. Helm Cheat Sheet (K8s Package Manager)

📦 Install Helm

brew install helm

🧰 Helm Usage

helm repo add bitnami https://charts.bitnami.com/bitnami
helm install myapp bitnami/nginx
helm upgrade myapp bitnami/nginx --set service.type=LoadBalancer
helm uninstall myapp

Benefits:

• Templated YAMLs
• Values override
• Reusable charts

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🔁 8. GitOps & ArgoCD

Tool	Purpose
ArgoCD	Pull-based GitOps deployments
Flux	Lightweight GitOps tool
Kustomize	Overlay-based YAML customizer

GitOps Flow:

1. Git repo holds app + infra YAMLs
2. ArgoCD syncs with Git
3. Changes are auto-deployed to the cluster

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📊 9. Observability & Monitoring

Type	Tool
Metrics	Prometheus
Dashboards	Grafana
Logs	Loki, Fluentd, EFK Stack
Tracing	Jaeger, OpenTelemetry
Alerting	Alertmanager, PagerDuty

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🤖 10. Advanced Topics

Topic	Description
Operators	Custom controllers for complex apps (e.g., DBs)
Custom Resource Definitions (CRDs)	Extend K8s API
Pod Disruption Budgets	Ensure availability during node upgrade
Multi-cluster deployments	Manage apps across regions/clouds
Service Mesh (Istio, Linkerd)	Traffic shaping, mTLS, telemetry
Admission Webhooks	Validate/Mutate requests dynamically

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🎯 Bonus: Kubernetes Interview Highlights

Topic	Sample Question
Pod Lifecycle	What are pod phases?
Rolling Updates	How does Kubernetes update apps without downtime?
Liveness vs Readiness	What’s the difference?
HPA	How does auto-scaling work in Kubernetes?
Network Policies	How do you restrict pod traffic?

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Cheat Sheet PDF

🧭 Final Learning Path

1️⃣ Start with: kubectl, Pods, Services
2️⃣ Deploy apps: Deployments, Ingress
3️⃣ Add CI/CD: GitHub Actions + YAML
4️⃣ Secure it: Secrets, RBAC
5️⃣ Scale it: HPA, Helm, ArgoCD
6️⃣ Observe it: Prometheus, Grafana
7️⃣ Extend it: CRDs, Operators

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🏁 Conclusion

Kubernetes is vast, but not impossible.

Use this cheat sheet as your guide — whether you’re:

• Preparing for an interview
• Managing production apps
• Learning Kubernetes from scratch

“If Docker runs containers, Kubernetes runs production.”

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