Interview Questions

1. How do you check system performance? Use multiple tools depending on need: top htop uptime vmstat 1 iostat -x 1 free -m sar -u 1 5 👉 Real-time: CPU bottleneck → check top & vmstat 2. How do you find high CPU consuming process? top ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%cpu | head Kill process: kill -9 3. How do you check memory usage? free -m cat /proc/meminfo top 4. Difference between soft link & hard link? ln file1 hardlink ln -s file1 softlink Hard link → same inode Soft link → pointer (like shortcut) 5. How do you find large files? find / -type f -size +100M du -ah / | sort -rh | head -20 6. How do you monitor logs in real-time? tail -f /var/log/messages tail -f /var/log/syslog 7. What is inode? Check inode: ls -i df -i 👉 Stores metadata of file 8. How do you manage disk space? df -h du -sh * Clean: rm -rf unwanted_files 9. How do you check open ports? netstat -tulnp ss -tulnp 10. How do you check running services? systemctl status nginx systemctl list-units --type=se...

Kubernestes inteview questions for experienced:
 🔥 Kubernetes Interview Questions with Commands 1. How do you check all resources in a cluster? kubectl get all 👉 Namespace specific: kubectl get all -n dev 2. How do you create a resource? kubectl apply -f deployment.yaml 3. How do you check pod details? kubectl describe pod pod-name 4. How do you check pod logs? kubectl logs pod-name 👉 Multi-container pod: kubectl logs pod-name -c container-name 5. How do you exec into a pod? kubectl exec -it pod-name -- /bin/bash 6. How do you check nodes? kubectl get nodes kubectl describe node node-name 7. How do you scale a deployment? kubectl scale deployment app-name --replicas=5 8. How do you check deployment status? kubectl get deployments kubectl describe deployment app-name 9. How do you check rollout status? kubectl rollout status deployment app-name 10. How do you rollback deployment? kubectl rollout undo deployment app-name 11. How do you check services...

Kuberneste interview questions: 1).🔥 Kubernetes Critical Interview Q&A (with Commands) ⚙️ 1. Pod Crash / Debugging Q: Pod is crashing. How do you troubleshoot? kubectl get pods kubectl describe pod kubectl logs kubectl logs --previous kubectl exec -it -- /bin/sh kubectl get events --sort-by=.metadata.creationTimestamp ⚙️ 2. Pod Pending Issue Q: Pod stuck in Pending state kubectl describe pod kubectl get nodes kubectl describe node kubectl get pvc kubectl describe pvc ⚙️ 3. Desired Pods ≠ Running Pods Q: Desired = 5, Running = 3 kubectl get deployment kubectl describe deployment kubectl get rs kubectl get pods -o wide kubectl describe pod kubectl get nodes kubectl top nodes 🌐 4. Service Not Reachable Q: Service is not accessible kubectl get svc kubectl describe svc kubectl get endpoints kubectl get pods -o wide kubectl exec -it -- curl kubectl exec -it -- nslookup 🌐 5. Networking Issue Between Pods kubectl exec -it -- ping kubectl exec -it -- curl ...

Advanced Linux Interview Questions (with Practical Focus) 🧠 1. What happens when you type a command in Linux? Flow: Shell receives command Checks PATH variable Finds binary (/bin, /usr/bin) Forks process Executes via exec() ⚙️ 2. How do you check CPU, Memory, and Disk usage? top htop free -m vmstat iostat df -h du -sh * 👉 Real-time: “If server is slow → first check top and iostat” 🔍 3. How do you find which process is using high CPU? top ps -eo pid,ppid,cmd,%mem,%cpu --sort=-%cpu | head Kill process: kill -9 📂 4. Difference between soft link and hard link? Feature Soft Link Hard Link Command ln -s ln Inode Different Same Works across FS Yes No If original deleted Broken Still works 🔐 5. File permissions (very important) chmod 755 file chown user:group file 👉 755 = rwxr-xr-x 🔥 6. What is inode? Stores metadata of file (size, owner, permissions) Does NOT store filename Check: ls -i df -i 🧪 7. What will you do if disk is full? df -h du -sh /* find / -size +100M 👉 Clear logs: tru...

Dokcer Interview Questions: ============================= 🔥 Advanced Practical Docker Interview Questions 🧱 1. Docker Architecture & Internals Q: Explain how Docker works internally when you run docker run nginx. 👉 Expected: Docker CLI → Docker Daemon → containerd → runc Image pull from registry Creation of container using namespaces & cgroups 🐳 2. Write a Dockerfile (Real Scenario) Q: Create a Dockerfile for a Node.js app. FROM node:18-alpine WORKDIR /app COPY package*.json ./ RUN npm install COPY . . EXPOSE 3000 CMD ["npm", "start"] 👉 Follow-up: How to reduce image size? Why use alpine? 📦 3. Multi-Stage Build (Very Important) Q: Optimize this Dockerfile for production. # Build stage FROM node:18 as builder WORKDIR /app COPY . . RUN npm install && npm run build # Production stage FROM nginx:alpine COPY --from=builder /app/build /usr/share/nginx/html 👉 Key concept: Reduce final image size Separate build & runtime 🔐 4. Secrets Handl...

🔥 1. Advanced Linux Basics (Expected Depth) ❓ What happens when you run a command in Linux? 👉 Expected: Shell interprets command Checks PATH Forks process Uses exec() system call Kernel schedules execution ❓ Difference between process and thread? Process = independent memory Thread = shared memory within process ❓ What is load average? 👉 Example: uptime 1 min, 5 min, 15 min CPU load Compare with CPU cores ⚙️ 2. Process Management (Scenario-Based) ❓ A process is consuming 100% CPU. What will you do? 👉 Steps: top / htop ps -ef | grep renice -n 10 -p kill -15 kill -9 ❓ Difference between kill -9 and kill -15? -15 (SIGTERM) → graceful -9 (SIGKILL) → force kill ❓ How to find parent-child process? pstree -p ps -ef --forest 💾 3. Memory Management ❓ How Linux manages memory? 👉 Answer: Physical memory + Swap Virtual memory Paging ❓ What is OOM Killer? 👉 When memory is full → kills high memory process ❓ Check memory usage? free -m vmstat top 📂 4. File System & Storage ❓ Differenc...