2025 Complete Linux Cloud Computing Interview Questions – 142 Essential Topics

Linux Interview Questions (11 Chapters)

I. Linux Overview

What is Linux?

Differences between Unix and Linux?

What is the Linux kernel?

What are the basic components of Linux?

Linux architecture

Key differences between BASH and DOS

Linux boot process

Default runlevels in Linux

Inter‑process communication methods used by Linux

System log files in Linux

Is installing multiple desktop environments helpful?

What is swap space?

What is the root account?

What is LILO?

What is BASH?

What is CL1?

What is GU1?

Advantages of open source

Importance of the GNU project

II. Disk, Directory, File

Simple Linux file system?

Linux directory structure

What is an inode?

Hard links vs. soft links

What is RAID?

III. Security

Security tasks after initializing a Linux system

What are CC attacks and DDOS attacks?

What is website database injection?

IV. Shell

What is a shell script?

Syntax basics

142 Linux Interview Questions

Disk usage detection (with shell script)

LVS load‑balancing strategies

Understanding of LVS

Principles of load balancing

Components of LVS

Terminology related to LVS

LVS‑NAT mode principle

Features of LVS‑NAT model

LVS‑DR mode principle

Features of LVS‑DR model

Comparison of three LVS load‑balancing modes

LVS scheduling algorithms

Differences between LVS and Nginx

Functions of load balancing

Nginx load‑balancing distribution strategies

What is keepalived?

Understanding of VRRP protocol

Working principle of keepalived

Causes of split‑brain in keepalived

How to resolve keepalived split‑brain

Monitoring split‑brain with Zabbix

Nginx load‑balancing implementation strategies

Common Nginx modules for load balancing

Various load‑balancing implementation methods

How Nginx implements layer‑4 load balancing

Common web services

Reasons for using Nginx

Why Nginx performance exceeds Apache

Components of epoll

Differences between Nginx and Apache

Advantages and disadvantages of Tomcat as a web server

Tomcat's three ports and their purposes

Differences between FastCGI and CGI

Common Nginx commands

Difference between reverse proxy and forward proxy

Differences among Squid, Varnish, and Nginx

How Nginx handles HTTP requests

Nginx virtual host types

How Nginx performs backend health checks

Difference between Apache Worker and Prefork

Default Tomcat port and how to change it

Tomcat's working mode

Tomcat request processing flow

Monitoring Tomcat memory usage

Optimizations you have done for Nginx

Optimizations you have done for Tomcat

How to handle Nginx session desynchronization

Common Nginx modules

Nginx status codes

Website access flow

TCP three‑way handshake and four‑way termination

Static vs. dynamic resources

Maximum concurrency supported by worker processes

Differences between Tomcat and Resin and selection criteria

What is gray‑scale release?

Analyze Nginx access logs to find top‑10 IPs by page views

Differences among Nginx versions

Latest Nginx version

58 Linux Interview Questions

Common Linux distributions

Viewing logs for a specific time range

Replace all occurrences of "old" with "new" in a file

Replace "old" with "new" between line n and line m

Count occurrences of a string in a file

Find lines containing a specific character

Count occurrences of keyword "abc" in log.txt

How to view Java processes

List ports the server is listening on

Find the process using port 8080

Check disk usage and directory usage in the current path

Recursively change owner and group of a directory

Change only owner or only group of a file

Set file permissions: owner read, group write, others execute

List all system users and groups

Add a user and change its password

View the currently logged‑in user