DEV Community: Bharat

🚀 Day 3 of #90DaysOfDevOps - Linux Fundamentals for DevOps Engineers

Bharat — Mon, 01 Jun 2026 12:35:17 +0000

🚀 Day 3 of #90DaysOfDevOps - Linux Fundamentals for DevOps Engineers

Welcome to Day 3 of my #90DaysOfDevOps journey.

This week, I started learning Linux Fundamentals, one of the most important skills for any DevOps Engineer. Almost every cloud platform, container platform, CI/CD tool, and production server relies heavily on Linux.

Understanding Linux is not optional for DevOps—it's essential.

🐧 What is Linux?

Linux is a free and open-source operating system based on Unix principles.

It is widely known for:

Stability
Security
Scalability
Performance
Flexibility

Linux powers servers, cloud platforms, containers, smartphones, and even supercomputers.

🌍 Why Linux Matters in DevOps

DevOps Engineers interact with Linux daily.

Common use cases include:

Managing cloud servers
Running Docker containers
Working with Kubernetes clusters
Setting up CI/CD pipelines
Monitoring applications
Automating deployments

Most production environments run on Linux, making it a must-have skill for every DevOps professional.

🏗️ Linux Architecture

Linux architecture consists of three major components:

1. Kernel

The Kernel is the core of the Linux operating system.

Responsibilities:

Process Management
Memory Management
Device Management
Hardware Communication

2. Shell

The Shell acts as an interface between the user and the operating system.

Popular shells:

Bash
Zsh
Fish

The shell allows users to execute commands and interact with the system.

3. Applications

Applications are software programs running on Linux.

Examples:

Docker
Jenkins
Git
Nginx
VS Code

📦 Popular Linux Distributions

Ubuntu

Beginner Friendly
Most popular for DevOps learning

Debian

Stable and Reliable
Commonly used in servers

Fedora

Latest Features
Developer Friendly

Kali Linux

Security Testing
Penetration Testing

Red Hat Enterprise Linux (RHEL)

Enterprise Grade Linux
Used in large organizations

💻 Essential Linux Commands

Check Current Directory

pwd

List Files and Directories

ls

Change Directory

cd directory_name

Create a Directory

mkdir myfolder

Remove a File

rm filename

Copy Files

cp source destination

Move Files

mv source destination

Check Running Processes

top

Check IP Address

ip addr

Test Network Connectivity

ping google.com

🔍 System Information Commands

Check Linux Kernel Version:

uname -r

Detailed System Information:

uname -a

Host Information:

hostnamectl

📖 Brief History of Linux

Linux was created by Linus Torvalds in 1991.

The goal was to build a free and open-source Unix-like operating system.

Over time, Linux became the backbone of:

Cloud Computing
Enterprise Servers
DevOps Platforms
Container Technologies
Cybersecurity Tools

🚀 Applications of Linux

Linux is widely used in:

Cloud Computing

AWS, Azure, and GCP heavily rely on Linux.

Server Hosting

Most web servers run Linux.

Software Development

Developers use Linux for building and testing applications.

Cybersecurity

Linux powers many security and penetration testing tools.

DevOps

Most DevOps tools are designed to run on Linux.

🎯 Key Learnings

✅ Linux Fundamentals

✅ Linux Architecture

✅ Kernel and Shell

✅ Linux Distributions

✅ Essential Linux Commands

✅ Linux System Information Commands

✅ Linux History

✅ Linux Use Cases in DevOps

📝 Conclusion

Linux is the foundation of modern DevOps practices. From cloud servers and containers to automation and monitoring, Linux plays a critical role in every stage of the DevOps lifecycle.

Building strong Linux fundamentals will make it easier to learn Docker, Kubernetes, Cloud Computing, CI/CD, and Infrastructure Automation in the coming weeks of my #90DaysOfDevOps journey.

Thank you for reading!

Happy Learning 🚀

90DaysOfDevOps #Linux #DevOps #CloudComputing #AWS #Azure #Kubernetes #Docker #OpenSource #LearningInPublic

Week 1 Report – Complete Networking for DevOps

Bharat — Sun, 31 May 2026 17:32:51 +0000

🚀 Week 1 Report – Complete Networking for DevOps

Welcome to my Week 1 report of the #90DaysOfDevOps challenge.

This week was focused entirely on Networking Fundamentals, one of the most important skills for every DevOps Engineer. Before learning Docker, Kubernetes, CI/CD, Cloud, or Infrastructure as Code, understanding networking is essential because every service communicates through a network.

🌐 Why Networking is Important in DevOps

Most production issues are related to networking:

DNS failures
Port connectivity issues
Load Balancer problems
Firewall restrictions
SSL/TLS certificate issues
Kubernetes networking problems
Cloud VPC misconfigurations

A DevOps Engineer spends a lot of time troubleshooting communication between services.

Understanding networking helps identify issues quickly and maintain reliable infrastructure. Many DevOps practitioners emphasize that networking fundamentals are critical for debugging cloud, Kubernetes, and infrastructure problems.

📚 OSI Model

The OSI (Open Systems Interconnection) Model explains how data travels across a network.

Layer	Name
7	Application
6	Presentation
5	Session
4	Transport
3	Network
2	Data Link
1	Physical

Physical Layer

Responsible for transmitting bits through cables and signals.

Examples:

Ethernet
Fiber Optics
Wireless Signals

Data Link Layer

Responsible for:

MAC Addressing
Error Detection
Frame Transmission

Device:

Switch

Network Layer

Responsible for:

IP Addressing
Routing
Packet Delivery

Device:

Router

Transport Layer

Provides end-to-end communication.

Protocols:

Functions:

Segmentation
Error Recovery
Flow Control

Session Layer

Responsible for:

Session Creation
Session Management
Session Termination

Presentation Layer

Responsible for:

Encryption
Compression
Data Formatting

Application Layer

Closest layer to the user.

Examples:

HTTP
HTTPS
DNS
FTP
SSH

🌍 TCP/IP Model

The TCP/IP Model is the practical implementation used on the Internet.

Layer	Function
Application	User Services
Transport	Communication
Internet	Routing
Network Access	Physical Network Access

Networking for DevOps is usually discussed using the TCP/IP model because it reflects real-world Internet communication.

🔄 OSI vs TCP/IP

OSI	TCP/IP
7 Layers	4 Layers
Theoretical Model	Practical Model
Developed by ISO	Developed by DARPA

🌐 IP Addressing

Every device on a network requires an IP Address.

Example:

192.168.1.10

Types:

Public IP

Accessible from the Internet.

Example:

8.8.8.8

Private IP

Used inside internal networks.

Examples:

192.168.x.x
172.16.x.x – 172.31.x.x
10.x.x.x

📦 Subnetting

Subnetting divides a large network into smaller networks.

Example:

192.168.1.0/24

Benefits:

Better Security
Better Network Management
Reduced Traffic

Subnetting and CIDR notation are foundational networking concepts used heavily in cloud environments and DevOps infrastructure.

🔢 CIDR Notation

CIDR = Classless Inter-Domain Routing

Examples:

/24 = 255.255.255.0
/16 = 255.255.0.0
/32 = Single Host

Example:

192.168.1.0/24

🔐 Common Networking Protocols

HTTP

Used for web communication.

Port:

Example:

http://example.com

HTTPS

Secure version of HTTP.

Port:

443

Provides:

Encryption
Security
Data Integrity

DNS

Domain Name System converts domain names into IP addresses.

Example:

google.com → IP Address

Without DNS, users would need to remember IP addresses.

DNS is consistently identified as one of the most important networking concepts for DevOps engineers.

SSH

Secure Shell is used for remote server access.

Port:

Example:

ssh user@server-ip

This is one of the most frequently used protocols in DevOps.

FTP

Used for file transfers.

Default Port:

SMTP

Used for sending emails.

⚡ TCP vs UDP

Feature	TCP	UDP
Connection	Yes	No
Reliability	High	Low
Speed	Slower	Faster
Error Checking	Yes	Minimal

TCP Examples

HTTP
HTTPS
SSH
FTP

UDP Examples

Gaming
Video Streaming
VoIP

Understanding TCP and UDP is considered a core networking requirement for DevOps professionals.

🔥 Ports Every DevOps Engineer Should Know

Service	Port
HTTP	80
HTTPS	443
SSH	22
FTP	21
SMTP	25
DNS	53
MySQL	3306
PostgreSQL	5432
Jenkins	8080
Kubernetes API	6443

🛡️ Firewalls

Firewalls control incoming and outgoing network traffic.

Examples:

AWS Security Groups
NACLs
Linux UFW
iptables

Purpose:

Security
Access Control
Traffic Filtering

⚖️ Load Balancers

Load Balancers distribute traffic across multiple servers.

Benefits:

High Availability
Scalability
Fault Tolerance

Examples:

NGINX
HAProxy
AWS ALB
AWS NLB

Load balancing and reverse proxies are commonly cited as networking concepts DevOps engineers should understand.

☁️ Networking in Cloud Computing

Cloud networking includes:

VPC
Subnets
Route Tables
NAT Gateway
Internet Gateway
Security Groups

Without networking knowledge, cloud architecture becomes difficult to understand.

☸️ Networking in Kubernetes

Networking is heavily used in Kubernetes:

Pods
Services
ClusterIP
NodePort
Ingress
Network Policies

Most Kubernetes communication depends on networking concepts.

🛠 Essential Networking Commands for DevOps

Check IP Address

ip addr

Check Connectivity

ping google.com

DNS Lookup

nslookup google.com

dig google.com

Check Open Ports

ss -tulpn

Trace Route

traceroute google.com

Test HTTP Response

curl -I https://google.com

Real-world DevOps troubleshooting often relies on commands like ping, dig, traceroute, curl, and port inspection tools.

🎯 Key Learnings From Week 1

✅ OSI Model

✅ TCP/IP Model

✅ IP Addressing

✅ Subnetting

✅ CIDR

✅ DNS

✅ HTTP/HTTPS

✅ SSH

✅ TCP vs UDP

✅ Firewalls

✅ Load Balancers

✅ Cloud Networking Basics

✅ Kubernetes Networking Basics

✅ Networking Troubleshooting Commands

🚀 Conclusion

Networking is not just another topic in DevOps.

It is the foundation behind cloud platforms, Linux servers, Docker containers, Kubernetes clusters, CI/CD pipelines, APIs, and distributed applications.

This week helped me understand how systems communicate, how requests travel across networks, and how DevOps engineers troubleshoot real-world infrastructure issues.

The stronger your networking fundamentals are, the easier it becomes to learn Cloud, Kubernetes, Security, and Site Reliability Engineering.

Thank you for reading my Week 1 report.

Happy Learning! 🚀

90DaysOfDevOps #DevOps #Networking #Linux #CloudComputing #AWS #Azure #Kubernetes #Docker #LearningInPublic #TechCommunity