DEV Community: Aisalkyn Aidarova

Docker Lab 3 – Docker Volumes (The Real Power of Docker)

Aisalkyn Aidarova — Thu, 09 Jul 2026 02:46:50 +0000

Duration: 45–60 minutes

Level: Beginner

Learning Objectives

After this lab students will understand:

What a Docker Volume (Bind Mount) is
Why DevOps engineers use volumes
Difference between copying files and mounting files
Why developers love Docker volumes
Live code changes without rebuilding Docker images

Real DevOps Scenario

Imagine a frontend developer is building a website.

Without Docker:

Edit HTML
↓

Upload to server

↓

Restart Nginx

↓

Refresh Browser

This is slow.

With Docker Volume:

Edit HTML

↓

Save

↓

Refresh Browser

↓

Changes appear instantly

This is exactly how many developers work locally.

Today's Goal

Instead of copying the website inside the Docker image,

we will let Docker use our local folder.

Mac Folder

↓

Docker Volume

↓

Container

↓

Browser

Step 1 Create Project

mkdir docker-volume-lab

cd docker-volume-lab

Step 2 Create Website

touch index.html

Open

nano index.html

Paste

<!DOCTYPE html>
<html>
<head>
    <title>Docker Volume Lab</title>
</head>

<body>

<h1>Docker Volume Lab</h1>

<h2>Hello Students!</h2>

<p>This file comes directly from my laptop.</p>

</body>
</html>

Save

CTRL+O

ENTER

CTRL+X

Step 3 Pull Nginx Image

docker pull nginx

Explain

We only download Nginx.

We do NOT create our own image today.

Step 4 Run Container Using Volume

docker run -d \
-p 8080:80 \
-v $(pwd):/usr/share/nginx/html \
--name volume-lab \
nginx

Explain Every Option

docker run

Create container

-d

Detached mode

Run in background

-p 8080:80

Laptop

8080

↓

Container

80

Browser connects to

localhost:8080

Nginx listens on

-v

Most important option today.

Volume

Bind Mount

$(pwd)

Means

Current Folder

Example

/Users/john/docker-volume-lab

:

Means

Connect

this folder

that folder

/usr/share/nginx/html

Nginx serves websites from this folder.

Instead of copying files,

Docker reads directly from your laptop.

Architecture

Mac

index.html

↓

Docker Volume

↓

Container

↓

Nginx

↓

Browser

Step 5 Check Running Container

docker ps

Expected

volume-lab

Up

Step 6 Open Browser

http://localhost:8080

Expected

Docker Volume Lab

Hello Students!

This file comes directly from my laptop.

Step 7 Change Website

Open

nano index.html

Change

<h2>Hello Students!</h2>

<h2>Hello DevOps Engineers!</h2>

Save.

Step 8 Refresh Browser

No Docker commands.

No rebuild.

No restart.

Just refresh.

Expected

Hello DevOps Engineers!

Explain Why

Docker is NOT storing the website.

Docker is reading directly from

your laptop.

Laptop File

↓

Docker

↓

Browser

Step 9 Verify Inside Container

Enter container

docker exec -it volume-lab bash

Go to

cd /usr/share/nginx/html

Check

ls

See

index.html

Open

cat index.html

Students will see

the updated file.

Explain

This file is NOT inside Docker.

Docker is reading it from the laptop.

Exit

exit

Step 10 Delete Website

Back on Mac

rm index.html

Refresh Browser.

Expected

404 Not Found

Why?

Because Docker is reading

the laptop folder.

If the laptop file disappears,

the website disappears.

Step 11 Stop Container

docker stop volume-lab

Step 12 Remove Container

docker rm volume-lab

Verify

docker ps -a

Container is gone.

Key Difference

Lab 1

Dockerfile

↓

COPY

↓

Image

↓

Container

Website lives

inside

the image.

Lab 3

Laptop

↓

Volume

↓

Container

Website stays

on the laptop.

Docker simply reads it.

Why DevOps Engineers Use Volumes

Volumes are commonly used for:

Local development (edit code without rebuilding images)
Sharing files between the host and containers
Persisting database data (e.g., MySQL, PostgreSQL)
Keeping logs outside containers
Storing uploaded files

Challenge Exercise

Ask students to:

Add their name to the page:

<h3>Created by Samara</h3>

Add today's date.
Change the background color:

<body style="background-color: lightblue;">

Refresh the browser.

No rebuild.

No restart.

If the changes appear immediately, they have successfully used a Docker volume.

Docker Lab 2: Build and Run a Python Web Application in Docker

Aisalkyn Aidarova — Thu, 09 Jul 2026 02:24:15 +0000

Goal

In this lab, students will learn how to:

Build a Docker image from a Python application.
Understand why developers use base images.
Install application dependencies.
Run a Python web server inside a container.
Access the application from a browser.
See how DevOps engineers package backend applications.

Real DevOps Scenario

Imagine a Python developer finishes building a REST API.

Without Docker, every server must have:

Python installed
pip installed
Required libraries installed
Correct Python version

This often causes problems.

Example:

Developer Laptop
Python 3.12
Flask 3.0

↓

Production Server

Python 3.9
Flask missing

↓

Application fails

Docker solves this problem by packaging everything together.

Step 1: Create the Project Folder

mkdir docker-python-lab
cd docker-python-lab

Step 2: Create the Application

Create app.py

touch app.py

Open it:

nano app.py

Paste:

from flask import Flask

app = Flask(__name__)

@app.route("/")
def home():
    return "<h1>Hello from Python inside Docker!</h1>"

@app.route("/about")
def about():
    return "<h2>This application is running inside a Docker container.</h2>"

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000)

Save.

Step 3: Create Requirements File

touch requirements.txt

Open:

nano requirements.txt

Add:

Flask==3.0.3

Save.

Why do we need `requirements.txt`?

Developers use this file to list all Python packages required by the application.

Instead of manually installing software, Docker reads this file and installs everything automatically.

Step 4: Create Dockerfile

touch Dockerfile

Paste:

FROM python:3.12-slim

WORKDIR /app

COPY requirements.txt .

RUN pip install --no-cache-dir -r requirements.txt

COPY . .

EXPOSE 5000

CMD ["python", "app.py"]

Explain Every Line

FROM

FROM python:3.12-slim

Downloads a lightweight Python image.

Instead of installing Python ourselves, Docker already has it prepared.

WORKDIR

WORKDIR /app

Creates and switches into the /app directory inside the container.

Every command after this runs from there.

COPY

COPY requirements.txt .

Copies only the requirements file first.

This improves Docker caching because dependencies usually change less often than the application code.

RUN

RUN pip install --no-cache-dir -r requirements.txt

Installs Flask inside the image.

COPY

COPY . .

Copies the rest of the application files.

EXPOSE

EXPOSE 5000

The Flask application listens on port 5000.

CMD

CMD ["python","app.py"]

Runs the application when the container starts.

Step 5: Build Image

docker build -t python-app:v1 .

Step 6: Check Images

docker images

Expected:

python-app
python

Step 7: Run Container

docker run -d -p 5000:5000 --name python-container python-app:v1

Step 8: Open Browser

Visit:

http://localhost:5000

You should see:

Hello from Python inside Docker!

Try:

http://localhost:5000/about

Step 9: View Logs

docker logs python-container

Step 10: Enter the Container

docker exec -it python-container bash

Inside the container:

pwd
ls
python --version
pip list

Exit:

exit

Step 11: Stop and Remove

docker stop python-container
docker rm python-container

What Students Learned

How Docker packages Python applications.
Why requirements.txt is important.
What WORKDIR, COPY, RUN, and CMD do.
How backend applications are containerized.

Docker Lab 3: Multi-Container Application with Docker Compose

Goal

Students will learn:

Why applications often have multiple services.
What Docker Compose is.
How containers communicate.
How DevOps engineers run full environments locally.

Real DevOps Scenario

A real application rarely consists of one container.

For example:

Browser
   │
   ▼
Frontend (React)
   │
   ▼
Backend API (Python)
   │
   ▼
Database (PostgreSQL)

Managing each container separately becomes difficult.

Docker Compose lets us define the entire environment in one file.

Step 1: Create the Project

mkdir docker-compose-lab
cd docker-compose-lab

Step 2: Create `index.html`

<!DOCTYPE html>
<html>
<head>
    <title>Docker Compose Lab</title>
</head>
<body>
    <h1>Docker Compose is Working!</h1>
</body>
</html>

Step 3: Create Dockerfile

FROM nginx:latest

COPY index.html /usr/share/nginx/html/

EXPOSE 80

Step 4: Create `docker-compose.yml`

version: "3.9"

services:

  website:
    build: .
    container_name: mywebsite

    ports:
      - "8080:80"

Explain the Compose File

version

Defines the Compose file format.

services

Lists all containers in the application.

Right now we only have one.

Later you can add:

frontend
backend
database
redis
rabbitmq

build

build: .

Build the image from the current directory.

container_name

Names the container.

ports

8080:80

Maps your laptop's port 8080 to port 80 inside the container.

Step 5: Start Everything

docker compose up -d

Compose will:

Build the image.
Create the container.
Start the container.

Step 6: Check Running Containers

docker ps

Step 7: Open Browser

http://localhost:8080

You should see:

Docker Compose is Working!

Step 8: View Logs

docker compose logs

Step 9: Stop Everything

docker compose down

This removes the container created by Docker Compose.

What Students Learned

Students now understand that:

Docker manages individual containers.
Docker Compose manages multiple containers together using a single configuration file.
In real DevOps environments, Compose is commonly used by developers for local testing, while orchestration platforms such as Kubernetes are used in production.

Docker Lab: Run a Simple Website in a Container

Aisalkyn Aidarova — Thu, 09 Jul 2026 01:57:09 +0000

Goal

By the end, students will understand:

What a Dockerfile is
What a Docker image is
What a Docker container is
How DevOps engineers package and run applications
How to expose an application to a browser

Real DevOps Scenario

A developer created a small website.

As a DevOps engineer, your job is to package this website into a Docker image so it can run the same way on:

your laptop
another developer’s laptop
a test server
production server
Kubernetes later

This solves the common problem:

It works on my machine, but not on the server.

Docker helps us make the environment consistent.

Step 1: Create Project Folder

mkdir docker-website-lab
cd docker-website-lab

Why?

We create one folder for our application files.

This folder will contain:

docker-website-lab
├── index.html
└── Dockerfile

Step 2: Create a Simple Website File

touch index.html

Open the file:

nano index.html

Paste this:

<!DOCTYPE html>
<html>
<head>
    <title>Docker Lab</title>
</head>
<body>
    <h1>Hello from Docker!</h1>
    <h2>This website is running inside a container.</h2>
    <p>Created by a DevOps student.</p>
</body>
</html>

Save:

CTRL + O
ENTER
CTRL + X

Why?

This is our simple application.

In real companies, this could be:

React frontend
Node.js backend
Python API
Java application

For beginners, we start with HTML because it is easy to see in the browser.

Step 3: Create a Dockerfile

touch Dockerfile

Open it:

nano Dockerfile

Paste this:

FROM nginx:latest

COPY index.html /usr/share/nginx/html/index.html

EXPOSE 80

Save:

CTRL + O
ENTER
CTRL + X

Step 4: Understand the Dockerfile

Line 1

FROM nginx:latest

Meaning

We are using an existing Nginx image.

Nginx is a web server.

A web server is responsible for showing websites in the browser.

Why DevOps engineers use this

Instead of installing Nginx manually on every server, we use a ready-made Docker image.

Without Docker:

Install Linux
Install Nginx
Configure Nginx
Copy website files
Start Nginx
Fix errors

With Docker:

Use nginx image
Copy website
Run container

Line 2

COPY index.html /usr/share/nginx/html/index.html

Meaning

Docker copies our website file into the Nginx web folder.

Nginx serves files from:

/usr/share/nginx/html/

Why DevOps engineers do this

The application must be inside the image.

When we move the image to another machine, the website goes with it.

Line 3

EXPOSE 80

Meaning

The container will listen on port 80.

Port 80 is the default HTTP web port.

Important

EXPOSE 80 does not publish the port to your laptop automatically.

It only documents that the application inside the container uses port 80.

We still need -p when running the container.

Step 5: Check Files

ls

Expected result:

Dockerfile  index.html

Why?

Before building the image, we must make sure Dockerfile and application files are in the same folder.

Step 6: Build Docker Image

docker build -t student-website:v1 .

Meaning

docker build

Build a Docker image.

-t student-website:v1

Give the image a name and version.

Use the current folder as the build context.

Docker will look for the Dockerfile in this folder.

Why DevOps engineers do this

In real DevOps work, we build Docker images after developers push code to GitHub.

Example CI/CD pipeline:

Developer pushes code
↓
GitHub Actions/Jenkins starts
↓
Docker image is built
↓
Image is tested
↓
Image is pushed to ECR/Docker Hub
↓
Application is deployed

Expected Result

You should see something like:

Successfully built ...
Successfully tagged student-website:v1

Step 7: Check Docker Images

docker images

Expected result:

REPOSITORY          TAG
student-website    v1
nginx              latest

What happened?

Docker created an image named:

student-website:v1

The image contains:

Nginx
Your index.html
Configuration needed to run the website

Step 8: Run Container

docker run -d -p 8080:80 --name my-website student-website:v1

Explain the command

docker run

Create and start a container.

-d

Detached mode. Run in the background.

-p 8080:80

Port mapping.

Port on your laptop.

Port inside the container.

--name my-website

Name the container.

student-website:v1

Image used to create the container.

Very Important Port Explanation

Container has its own private network.

Nginx runs inside the container on port 80.

Your laptop browser cannot directly access container port 80 unless we publish it.

That is why we use:

-p 8080:80

Meaning:

Browser on laptop
http://localhost:8080
        ↓
Docker forwards traffic
        ↓
Container port 80
        ↓
Nginx
        ↓
index.html

Step 9: Check Running Container

docker ps

Expected result:

CONTAINER ID   IMAGE                PORTS
abc123         student-website:v1   0.0.0.0:8080->80/tcp

Meaning

The container is running.

Port 8080 on your computer is connected to port 80 inside the container.

Step 10: Open Website

Open browser:

http://localhost:8080

Expected result:

Hello from Docker!
This website is running inside a container.
Created by a DevOps student.

What did we achieve?

We packaged and ran a website inside Docker.

The website is not running directly on your laptop.

It is running inside a container.

Step 11: View Container Logs

docker logs my-website

Why?

DevOps engineers check logs to troubleshoot applications.

When something is not working, logs help answer:

Did the app start?
Did users send requests?
Are there errors?
Is the app crashing?

When you refresh the browser, logs should show HTTP requests.

Step 12: Enter the Container

docker exec -it my-website bash

Now you are inside the container.

Run:

pwd

ls

cd /usr/share/nginx/html

ls

cat index.html

Exit:

exit

Why?

DevOps engineers sometimes enter containers to troubleshoot.

For example:

check files
check environment variables
check running processes
check configuration

But in production, we avoid changing things manually inside containers.

Containers should be recreated from images.

Step 13: Stop Container

docker stop my-website

Check:

docker ps

Expected result:

No running container named my-website

But if you run:

docker ps -a

You will still see it.

Meaning

docker stop stops the container, but does not delete it.

Step 14: Start Container Again

docker start my-website

Check:

docker ps

Open again:

http://localhost:8080

Meaning

The same stopped container can be started again.

Step 15: Remove Container

docker rm -f my-website

Meaning

This deletes the container.

The image still exists.

Check:

docker images

You should still see:

student-website   v1

Step 16: Run Again from Same Image

docker run -d -p 8080:80 --name my-website student-website:v1

Important Lesson

Even after deleting the container, we can create a new container from the same image.

Image = template
Container = running instance

Example:

One image
↓
Many containers

Step 17: Make a Change to Website

Open index.html again:

nano index.html

Change this line:

<h1>Hello from Docker!</h1>

to:

<h1>Hello from Docker Version 2!</h1>

Save.

Step 18: Rebuild Image as Version 2

docker build -t student-website:v2 .

Check images:

docker images

Expected:

student-website   v1
student-website   v2

Why?

In real DevOps, every code change should create a new image version.

Examples:

payment-service:v1
payment-service:v2
payment-service:v3

This helps with:

deployments
rollbacks
release tracking
troubleshooting

Step 19: Replace Running Container with New Version

Stop and remove old container:

docker rm -f my-website

Run version 2:

docker run -d -p 8080:80 --name my-website student-website:v2

Open:

http://localhost:8080

Expected result:

Hello from Docker Version 2!

Step 20: Clean Up

docker rm -f my-website

docker rmi student-website:v1

docker rmi student-website:v2

Optional:

docker rmi nginx:latest

Final Explanation for Students

Today you acted like a DevOps engineer.

You did this workflow:

Created application file
↓
Created Dockerfile
↓
Built Docker image
↓
Ran container
↓
Opened application in browser
↓
Checked logs
↓
Entered container
↓
Stopped and started container
↓
Created new version
↓
Redeployed new version

Key Concepts

Dockerfile

A recipe that tells Docker how to build an image.

Image

A packaged application with everything needed to run.

Container

A running instance of an image.

Port Mapping

Connects your computer port to the container port.

localhost:8080 → container:80

DevOps Purpose

DevOps engineers use Docker to make applications:

portable
repeatable
consistent
easy to deploy
easy to scale
easier to run in Kubernetes later

Lab 1 Personal Portfolio Repository ⭐

Aisalkyn Aidarova — Tue, 07 Jul 2026 00:25:06 +0000

Goal: Learn the complete Git workflow.

Task

Create a GitHub account (if don't have one).
Create a new repository called:

   my-first-repository

Clone it to their computer.
Inside it create:

my-first-repository/
│
├── README.md
├── about.txt
└── hobbies.txt

README.md

# My First GitHub Repository

Name:
Country:
Career Goal:

about.txt

I am learning DevOps.

hobbies.txt

Reading
Traveling
Sports

Then execute:

git clone
cd my-first-repository

git status

git add .

git commit -m "Initial commit"

git push origin main

Lab 2: Git Status

Give students these tasks.

Create

project/

Inside:

notes.txt
commands.txt

Questions:

Run git status
Which files are untracked?
Stage only notes.txt
Check status again.
Commit only that file.
What happens to commands.txt?

They learn

Untracked
Staged
Committed

Lab 3: Git History

Students make 5 commits.

Commit 1
Create README

Commit 2
Add Linux commands

Commit 3
Add Git commands

Commit 4
Fix typo

Commit 5
Add contact info

Then run

git log

Questions

How many commits?
Which commit is newest?
Which command shows commit history?

Lab 4: Practice Repository

Students create

devops-lab

Structure

devops-lab/

README.md

linux.txt

aws.txt

terraform.txt

Each file contains

Linux commands

AWS services

Terraform definition

Push everything to GitHub.

Lab 5: Clone Someone Else's Repository

Partner activity.

Student A

Creates repository
Pushes files

Student B

git clone

Verify files exist.

This teaches GitHub collaboration.

Lab 6: Intentional Mistakes

Give them commands out of order.

Example

git commit -m "first"

What happens?

Expected:

nothing to commit

Then ask

"What command did you forget?"

Answer

git add .

Lab 7: Fill in the Missing Commands

1. Create repository on GitHub.

2. _________
(download repository)

3. _________
(check current status)

4. _________
(stage all files)

5. _________
(save changes locally)

6. _________
(upload changes to GitHub)

Answers

git clone
git status
git add .
git commit -m ""
git push origin main

Lab 8: Final Practical Exam (30 minutes)

Students must create

student-project/

README.md
linux.txt
git.txt
aws.txt

Requirements

Initialize Git.
Connect to GitHub.
Stage all files.
Commit with:

  Initial project

Push to GitHub.

Commands they should use:

git init
git remote add origin
git status
git add .
git commit -m "Initial project"
git push -u origin main

Bonus Challenge

Ask students to modify README.md by adding:

Their favorite Linux command
Why they want to learn DevOps
The date they completed the lab

Then they should:

git add README.md
git commit -m "Update README"
git push

This gives them experience making multiple commits to the same repository.

These labs cover the essential Git workflow:

✅ Creating a repository
✅ Cloning
✅ Checking status
✅ Staging files
✅ Committing changes
✅ Viewing history
✅ Pushing to GitHub
✅ Making additional commits

This is an appropriate foundation before introducing branching, merging, pull requests, and resolving merge conflicts.

Lab: Build a Simple AWS Infrastructure

Aisalkyn Aidarova — Wed, 01 Jul 2026 00:06:01 +0000

Objective

Deploy a Linux server, connect it to a MySQL database, create storage, and upload files to S3.

Services covered:

EC2
Linux
RDS MySQL
EBS
EFS
S3

Part 1 – EC2 (20%)

Task 1

Create an Ubuntu EC2 instance.

Requirements:

Name: student-ec2
Instance type: t2.micro
Create a new Security Group
Allow SSH (22)

Task 2

Connect using SSH.

Run:

hostname
whoami
pwd
df -h
free -h
lsblk

Explain what each command shows.

Part 2 – EBS (20%)

Create a new EBS volume.

Requirements:

5 GB
Same Availability Zone as EC2

Attach it.

On Ubuntu:

lsblk
sudo mkfs.ext4 /dev/nvme1n1
sudo mkdir /data
sudo mount /dev/nvme1n1 /data
df -h

Create:

echo "JumpToTech" > /data/test.txt
cat /data/test.txt

Part 3 – EFS (15%)

Create:

EFS
Mount Target

Mount it on EC2.

Create:

sudo mkdir /efs

Mount.

Create:

echo "Hello EFS" > /efs/file1.txt

Verify.

Part 4 – S3 (15%)

Create bucket:

student-firstname-lastname

Upload

resume.pdf

hello.txt

Create another file on EC2.

Upload using AWS CLI.

Example:

aws s3 cp hello.txt s3://bucket-name/

List objects.

Part 5 – RDS MySQL (20%)

Create:

MySQL
admin user

Connect EC2 to RDS.

Install MySQL Client.

Connect.

Run:

SHOW DATABASES;

Create:

CREATE DATABASE school;

Use it:

USE school;

Create table:

CREATE TABLE students(
id INT AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(50),
course VARCHAR(50)
);

Insert:

INSERT INTO students(name,course)
VALUES
('John','DevOps'),
('Emma','AWS');

Verify:

SELECT * FROM students;

Part 6 – Linux (10%)

Create user:

sudo adduser devops

Create group:

sudo groupadd engineers

Add user:

sudo usermod -aG engineers devops

Create:

mkdir project

Create:

touch project/app.log

Change owner:

sudo chown devops:engineers project

Verify.

Deliverables

Students should submit screenshots of:

EC2 Running
SSH Connected
df -h
lsblk
Mounted EBS
Mounted EFS
S3 Bucket
Uploaded Object
RDS Available
MySQL Connection
SHOW DATABASES;
SELECT * FROM students;

Bonus Questions (Interview Style)

What is the difference between EBS and EFS?
Why can't we SSH into RDS?
Why did we install MySQL Client on EC2?
Why is port 3306 used?
What is the purpose of a Security Group?
Why is RDS a managed service?
What is the difference between S3 and EBS?
Why must the EBS volume be in the same Availability Zone as the EC2 instance?
Can two EC2 instances use the same EBS volume simultaneously?
When would you choose EFS instead of EBS?

This lab is realistic, reinforces all the services they've learned, and introduces the way a DevOps engineer connects compute, storage, networking, and databases in a simple production-like environment.

Build Your First Website with AI Using Jules and GitHub

Aisalkyn Aidarova — Sat, 27 Jun 2026 13:34:32 +0000

What are we going to build?

Today we are going to create a real business website without writing code.

Imagine you own:

A trucking company
A beauty salon
A restaurant
A dental office
A law firm

Normally, you would hire a web developer.

Today, instead of hiring a developer, we will hire an AI Software Engineer called Jules.

Step 1 – Create a GitHub Account

Go to:

https://github.com

Click Sign Up.

Why?

Think of GitHub as Google Drive for programmers.

Instead of storing Word documents, GitHub stores software projects.

Your AI developer (Jules) needs a place to save your website.

Step 2 – Create a New Repository

After logging into GitHub:

Click

New Repository

Repository Name:

my-first-website

beauty-salon

trucking-company

Choose

✅ Public

Click

Create Repository

Congratulations!

You just created an empty project.

Think of it as an empty folder waiting for files.

Step 3 – Open Jules

Go to

https://jules.google.com

The first time you use Jules it will ask permission to connect to GitHub.

Click

Authorize GitHub

Now Jules can work inside your GitHub repositories.

Think of Jules as your software engineer.

Step 4 – Select Your Repository

Inside Jules choose

my-first-website

Now Jules knows exactly where to create your website.

This is just like telling a real employee

"Please save everything inside this folder."

Step 5 – Tell Jules What You Want

Example prompt

Create a professional website for my trucking company.

Company Name:
Freedom Trucking LLC

The website should include:

Home
About
Services
Fleet
Testimonials
Contact
Quote Request Form

Use HTML, CSS and JavaScript.

Create a professional project structure.

Commit all files to my GitHub repository.

Then click

Start

Step 6 – Jules Starts Working

Now Jules behaves exactly like a software engineer.

It creates files such as

index.html

style.css

script.js

It organizes everything.

Then Jules automatically saves everything into your GitHub repository.

This is called a commit.

Think of a commit as pressing Save.

Step 7 – Review the Changes

Jules will often create something called a Pull Request.

What is a Pull Request?

Imagine an employee says

"I finished my work.

Would you like to review it before adding it to the project?"

That review request is called a Pull Request.

If everything looks good

Click

Merge Pull Request

Now your website officially becomes part of your project.

Step 8 – Open Your Repository

Go back to GitHub.

Now you should see

index.html

css

js

Your website is now safely stored in GitHub.

But...

Can people visit your website?

NO.

GitHub stores your files.

It is not yet showing your website to the world.

Step 9 – Publish Your Website

Click

Settings

↓

Pages

You will see

Source

Choose

Deploy from Branch

Choose

Branch

main

Folder

/(root)

Click

Save

Wait about one minute.

GitHub now copies your files onto its web servers.

This is called hosting.

Hosting simply means:

Your website files are now stored on computers that are connected to the Internet 24 hours a day.

Step 10 – Your Website Gets a Public Address

After about one minute GitHub displays something similar to

https://yourusername.github.io/my-first-website

This is your public website.

Now anyone in the world can visit it.

Congratulations!

You are now the owner of a real website.

What is Hosting?

Before publishing

Your files looked like this

My Laptop

index.html
style.css
script.js

Only YOU could open them.

After enabling GitHub Pages

GitHub Servers

index.html
style.css
script.js

Now everyone can visit.

Hosting simply means

"Putting your website onto computers connected to the Internet."

Why Do We Need a Domain Name?

GitHub gave us

https://yourusername.github.io/my-first-website

This works perfectly.

But it doesn't look very professional.

Instead you may want

www.freedomtrucking.com

www.annassalon.com

www.bestrestaurant.com

Step 11 – Buy a Domain Name

You can purchase a domain from companies like

GoDaddy
Namecheap
Cloudflare Registrar

Buying a domain does NOT create a website.

It simply reserves the name.

Think of it as buying the street address for your business.

Step 12 – Connect the Domain

After buying your domain

Open your domain provider.

Find

DNS Management

GitHub Pages will tell you exactly which DNS records to add.

Usually you will add:

A records
or CNAME records

Example

www.freedomtrucking.com
        │
        ▼
GitHub Pages
        │
        ▼
Your Website

Visitors type

www.freedomtrucking.com

GitHub automatically shows your website.

You no longer need the long GitHub URL.

Understanding the Entire Process

Business Owner

↓

"I need a website."

↓

Jules (AI Software Engineer)

↓

Creates Website Files

↓

GitHub

↓

Stores Project

↓

GitHub Pages

↓

Publishes Website

↓

Public URL

↓

Optional Custom Domain

↓

Customers Visit Your Website

Simple Definitions

GitHub

Stores your project.

Jules

Creates your website.

Commit

Saving changes.

Pull Request

Asking for approval before saving work.

Merge

Accepting the changes.

GitHub Pages

Makes your website available on the Internet.

Hosting

A computer connected to the Internet that stores and serves your website.

Domain Name

A friendly website address like

www.mybusiness.com

DNS

The system that connects your domain name to where your website is hosted.

Final Thought

Today, you did not learn programming.

You learned how modern businesses create websites using Artificial Intelligence.

You described your business.

AI wrote the code.

GitHub stored it.

GitHub Pages published it.

With one more step—a custom domain—your website becomes your professional online presence.

Linux Lab 1 – Build Your Own Linux Server

Aisalkyn Aidarova — Fri, 26 Jun 2026 23:54:17 +0000

Objective

Become comfortable managing a Linux server without looking up commands.

Tasks

Connect to the server using SSH.
Check:

   whoami
   hostname
   pwd
   uname -a

Create the following structure:

   /company
       /dev
       /qa
       /prod
       /backup

Create users:

developer
tester
devops

Create groups:

developers
testers
admins

Add each user to the proper group.
Verify everything.

What they learn

Linux hierarchy
Users
Groups
Ownership

Linux Lab 2 – Permissions Challenge

Students receive this situation:

"The developer cannot deploy because Permission denied appears."

They must solve it.

Tasks

Create

mkdir /application
touch app.log

Give wrong permissions.

Students must investigate.

Commands allowed

ls -l
chmod
chown
chgrp
id
groups

Questions

Why did Permission denied happen?
Which permission is missing?
Difference between owner, group, others?

Linux Lab 3 – File System Investigation

Students must answer

Where are these stored?

Users
Passwords
Groups
Services
Logs
Nginx config
SSH config
DNS configuration

Commands

cat /etc/passwd
cat /etc/group
cat /etc/hosts
cat /etc/resolv.conf

Find

/etc

/var

/home

/usr

/opt

/tmp

/proc

/dev

Goal

Understand the Linux directory structure.

Linux Lab 4 – Searching Like a DevOps Engineer

Find

A file named

production.log

Find all

*.conf

Find all files larger than 100 MB.

Find all files modified today.

Find every occurrence of

database

Commands

find
locate
grep
which
whereis

Linux Lab 5 – Package Management

Install

nginx
git
tree
curl
wget
htop

Verify installation.

Remove one package.

Reinstall it.

Questions

What is apt?
What is a repository?
Why update before installing?

Linux Lab 6 – Processes

Run

sleep 500

Open another terminal.

Find it.

Kill it.

Start nginx.

Stop nginx.

Restart nginx.

Check status.

Commands

ps
top
htop
kill
killall
systemctl
journalctl

Questions

Difference between process and service?
Why doesn't killing a process always stop a service permanently?

Linux Lab 7 – Storage

Students investigate

df -h
du -sh /*
lsblk
mount

Questions

Which disk is mounted?

How much free space remains?

Which folder consumes the most space?

Linux Lab 8 – Logs

Students must investigate

Someone attempted to log in but failed.

Find

SSH logs

System logs

Kernel logs

Nginx logs

Commands

journalctl

tail

less

grep

Questions

Why are logs critical in DevOps?

Linux Lab 9 – CPU & Memory

Run

yes > /dev/null

Investigate

top

Kill it.

Run memory test

stress-ng --vm 2 --vm-bytes 512M

Investigate

free -h

vmstat

Questions

What happens when CPU reaches 100%?

What happens when RAM is exhausted?

Linux Lab 10 – Services

Students manage

nginx
ssh
cron

Commands

systemctl start

systemctl stop

systemctl restart

systemctl reload

systemctl enable

systemctl disable

systemctl status

Questions

Difference between

Start

Restart

Reload

Enable

Disable

Linux Lab 11 – Bash

Write scripts

Example

#!/bin/bash

echo "Today's date:"
date

echo "Current user:"
whoami

echo "Current directory:"
pwd

Second script

Backup

cp -r /company /backup

Third

mkdir project{1..10}

Linux Lab 12 – Troubleshooting Challenge (Best One)

Do not tell students what is wrong.

Break the server before class:

Stop nginx.
Delete the website.
Fill the disk to 95%.
Change permissions.
Stop SSH.
Remove a user from the sudo group.
Kill a process.
Rename a configuration file.

Then give them only this ticket:

Incident #1045

Users report that the website is unavailable. The developer cannot deploy new code. The server is running slowly. Investigate and restore the server.

They can use any Linux commands they've learned, but they must document:

What symptoms they observed.
Which commands they used.
The root cause.
The fix they applied.
How they verified the issue was resolved.

This mirrors real DevOps work much better than following a list of commands. In production, engineers are rarely told what is broken—they have to investigate, identify the root cause, and restore the service. This kind of lab builds both Linux confidence and troubleshooting skills, which are exactly what employers look for in junior DevOps engineers.

linux lab

Aisalkyn Aidarova — Fri, 26 Jun 2026 00:01:46 +0000

Lab 1 – Linux Navigation & Files (20 points)

Task 1

Create the following structure.

/home/student/
├── project
│   ├── logs
│   ├── scripts
│   └── backup

Requirements

create all directories
create

app.log
error.log
install.sh

inside correct folders.

Task 2

Move

app.log

into

backup

Task 3

Delete

error.log

Task 4

Find

install.sh

using only one command.

Lab 2 – Permissions (20 points)

Create

secret.txt

Requirements

Owner

read/write

Group

read

Others

no access

Verify permissions.

Create a new user

developer

Switch to that user.

Can the user read

secret.txt

Explain why.

Lab 3 – Processes (20 points)

Start a process

Example

sleep 500

Questions

Find

Kill the process

Verify it stopped.

Bonus

Find the top five processes using the most memory.

Lab 4 – Disk Space (20 points)

Create a directory

practice

Generate a file about 100 MB.

Questions

How much disk space is used?

How much free disk space remains?

Which command shows directory size?

Lab 5 – Networking (30 points)

Find

Your

hostname
private IP
default gateway
DNS server

Ping

8.8.8.8

Questions

Did it work?

Ping

google.com

If this fails but

8.8.8.8

works,

what is the problem?

Display

All listening ports.

What service is listening on port 22?

Lab 6 – Troubleshooting (40 points)

Scenario 1

A user says

"Internet is not working."

Show the commands you would run.

Expected ideas

ip addr
ping 8.8.8.8
ping google.com
ip route
cat /etc/resolv.conf

Explain each step.

Scenario 2

A website is down.

Questions

How do you verify

server is running?
nginx is running?
port 80 is listening?
firewall issue?
logs?

Commands should include

systemctl status nginx

journalctl -u nginx

ss -tuln

curl localhost

systemctl restart nginx

Scenario 3

SSH stopped working.

How would you troubleshoot?

Expected

ping server

ssh localhost

systemctl status ssh

ss -tulpn

journalctl -xe

systemctl restart ssh

Lab 7 – Mixed Practical (Best Assessment)

Tell students:

You are the new Junior DevOps Engineer.

The manager asks you to prepare a server.

Complete all tasks.

Task 1

Create user

developer

Task 2

Create

/opt/application

Task 3

Create

run.sh

Make it executable.

Task 4

Create a file

server.log

containing

Application started

Task 5

Find your IP address.

Task 6

Show free disk space.

Task 7

Start

sleep 300

Find its PID.

Terminate it.

Task 8

Find every

*.log

file under

/opt

Task 9

Display the routing table.

Task 10

Explain the difference between

ping 8.8.8.8

and

ping google.com

Oral Questions (Ask During the Lab)

What is the difference between a process and a service?
Why do we need DNS?
What is the difference between a private IP and a public IP?
What happens when you type google.com into a browser?
What is the purpose of the default gateway?
What does chmod 755 mean?
What is the difference between find and locate?
What does sudo actually do?
Why do Linux servers typically not have a graphical interface?
If a website is down, what would you check first and why?

This is a very strong DevOps / Cloud Engineer interview preparation list.

Aisalkyn Aidarova — Wed, 24 Jun 2026 00:12:32 +0000

1. What is Hardware?

Hardware is any physical component of a computer system.

Examples:

CPU
RAM
SSD/HDD
Motherboard
Network Card
Power Supply
Keyboard
Monitor

Think of hardware as everything you can physically touch.

2. What is Software?

Software is a set of instructions that tell hardware what to do.

Examples:

Operating Systems

Linux
Windows
macOS

Applications

Browser
Microsoft Word
Zoom
Slack

Programming Languages

Python
Java
JavaScript

3. What is CPU?

CPU = Central Processing Unit

CPU is the brain of the computer.

Responsibilities:

Execute instructions
Perform calculations
Process requests
Run applications

Example:

When opening Chrome:

CPU receives command
CPU processes instruction
RAM stores temporary data
Chrome appears on screen

Interview Question:

What happens if CPU reaches 100% utilization?

Answer:

System becomes slow
Applications freeze
Response time increases
Requests queue up

Troubleshooting:

top
htop

Check CPU-consuming processes.

4. What is RAM?

RAM = Random Access Memory

Temporary memory.

Stores:

Running applications
Active processes
Temporary data

Example:

When opening:

Chrome
VS Code
Slack

All are loaded into RAM.

Important:

RAM is volatile.

If power is lost:

RAM data disappears.

Interview Question:

Difference between RAM and SSD?

RAM:

Faster
Temporary
Volatile

SSD:

Slower than RAM
Permanent
Persistent

5. What is SSD?

SSD = Solid State Drive

Permanent storage.

Stores:

OS
Applications
Documents
Databases

Advantages:

Faster than HDD
No moving parts
Better performance

Commands:

df -h
lsblk

6. What is a Server?

A server is a computer that provides services to other computers.

Examples:

Web Server
Database Server
Mail Server

Example:

User requests:

www.amazon.com

Request reaches server.

Server returns webpage.

7. What is a Virtual Machine?

VM = Virtual Machine

A software-based computer.

Runs on physical hardware.

Example:

One physical server:

64 CPU
256 GB RAM

Can host:

VM1
VM2
VM3
VM4

Benefits:

Isolation
Cost savings
Scalability

Examples:

VMware
VirtualBox
Hyper-V
EC2

8. What is Linux?

Linux is an operating system.

Responsibilities:

Process management
Memory management
User management
File system management

Common Commands:

pwd
ls
cd
mkdir
rm
cp
mv

Process Commands:

ps -ef
top
htop
kill -9 PID

Disk Commands:

df -h
du -sh

Memory:

free -m

9. Linux Troubleshooting

Server Slow

Check:

top

Questions:

CPU high?
Memory high?
Disk full?

Disk Full

df -h

Find large files:

du -sh /*

Application Down

Check:

systemctl status nginx

Logs:

journalctl -xe

10. What is Networking?

Networking allows devices to communicate.

Example:

Laptop → Router → Internet → Server

11. What is IP Address?

Unique address assigned to device.

Example:

192.168.1.10

Like a home address.

12. What is Router?

Router connects different networks.

Example:

Home Network
     |
 Router
     |
Internet

Functions:

Route traffic
NAT
Internet connectivity

13. What is Switch?

Switch connects devices within same network.

Example:

PC1
PC2
Printer
Server

All connected to switch.

Switch uses MAC addresses.

Router uses IP addresses.

Interview Question:

Router vs Switch?

Switch:

Same network
MAC address

Router:

Different networks
IP address

14. What is Load Balancer?

Distributes traffic across servers.

Example:

Users
  |
Load Balancer
 |
 |---- Server1
 |---- Server2
 |---- Server3

Benefits:

High Availability
Scalability
Fault Tolerance

AWS Types:

15. What is EC2?

EC2 = Elastic Compute Cloud

AWS virtual machine service.

Features:

CPU
RAM
Storage
Networking

Use cases:

Web servers
Applications
Databases

Entity: Amazon Web Services EC2 is one of the core compute services.

16. What is EBS?

EBS = Elastic Block Store

Storage attached to EC2.

Think:

EC2 = Computer
EBS = Hard Drive

Characteristics:

Block storage
Persistent
Snapshot support

Types:

Interview:

Can EBS exist without EC2?

Yes.

Volume remains after instance termination if configured.

17. What is EFS?

EFS = Elastic File System

Shared storage.

Many EC2s can mount same filesystem.

Example:

EC2-1
EC2-2
EC2-3
   |
   EFS

Use:

Shared files
Web content
Kubernetes shared storage

Difference:

EBS:

Single instance typically

EFS:

Multiple instances

18. What is S3?

S3 = Simple Storage Service

Object storage.

Stores:

Images
Videos
Logs
Backups

Features:

Highly durable
Scalable
Versioning
Lifecycle Policies

Example:

Store:

photo.jpg
backup.zip
logs.tar

inside bucket.

19. What is IAM?

IAM = Identity and Access Management

Controls permissions.

Components:

IAM User

Permanent identity.

IAM Group

Collection of users.

IAM Policy

Permissions document.

IAM Role

Temporary permissions.

Interview:

User vs Role?

User:

Permanent

Role:

Temporary

20. What is SAML?

SAML = Security Assertion Markup Language

Used for Single Sign-On (SSO).

Example:

Employee logs into:

Company Portal

Automatically accesses:

AWS
Salesforce
Workday

without re-entering password.

Flow:

User
 |
Identity Provider
 |
AWS

Examples:

Okta
Microsoft Entra ID

21. What is OpenID Connect (OIDC)?

Modern authentication protocol.

Built on OAuth 2.0.

Used by:

Google Login
GitHub Login
Microsoft Login

Example:

Login with Google

Website trusts Google.

Google verifies identity.

Website receives token.

Difference:

SAML:

XML
Enterprise

OIDC:

JSON/JWT
Modern Cloud Apps

22. What is API Gateway?

API Gateway receives API requests.

Example:

User
 |
API Gateway
 |
Lambda

Responsibilities:

Authentication
Authorization
Rate limiting
Routing

23. What is Lambda?

Lambda is serverless compute.

You upload code.

AWS manages servers.

Example:

User Uploads File
      |
      S3
      |
   Lambda

Lambda executes automatically.

Benefits:

No server management
Pay only when used
Auto scaling

24. What is Auto Scaling Group (ASG)?

Automatically adjusts EC2 count.

Example:

Traffic increases:

2 EC2
→
6 EC2

Traffic decreases:

6 EC2
→
2 EC2

Benefits:

Cost savings
High availability

25. Most Common Troubleshooting Questions

Website Not Loading

Check:

ping
nslookup
curl

Questions:

DNS working?
Server up?
Application running?
Security Group open?

EC2 Reachable but Website Not Working

Check:

systemctl status nginx

Check:

netstat -tulpn

ss -tulpn

Verify service listening on port 80.

High CPU

top

Find process.

Possible causes:

Infinite loop
Memory leak
Too many requests

High Memory

free -m

Check:

ps aux --sort=-%mem

Cannot SSH to Server

Verify:

Instance running
Security Group allows port 22
Correct key pair
NACL allows traffic
Route table correct

Internet Not Working

Check:

ping 8.8.8.8

If works:

DNS issue.

Check:

nslookup google.com

Most Important Interview Question

Explain how a user opens a website from browser.

Answer:

User types URL.
DNS resolves domain to IP.
Browser sends request.
Router forwards traffic.
Internet routes packet.
Load Balancer receives request.
Load Balancer sends request to EC2.
Application processes request.
Database returns data.
EC2 sends response back.
Browser displays webpage.

This question tests networking, DNS, servers, load balancers, applications, and cloud knowledge all at once.

This is a strong interview-preparation guide for a DevOps/SRE/Cloud Engineer role.

Aisalkyn Aidarova — Tue, 23 Jun 2026 00:05:39 +0000

1. What is an Operating System (OS)?

Interview Question

What is an Operating System?

Answer

An Operating System (OS) is software that acts as an interface between users/applications and computer hardware.

Responsibilities:

Process management
Memory management
File system management
Device management
Security and permissions
Networking

Examples:

Linux
Windows
macOS

Real Life Example

When you open Chrome:

Chrome requests CPU resources.
OS allocates RAM.
OS schedules CPU time.
OS accesses files from disk.
OS displays output on screen.

Without an OS, hardware cannot be efficiently utilized.

2. What Happens When You Type a Command in Linux?

Example

ls

Answer

User enters command in Shell.
Shell sends request to Kernel.
Kernel schedules process.
CPU executes instructions.
Output returned to Shell.
Shell displays result.

Flow:

User
 ↓
Shell
 ↓
Kernel
 ↓
CPU/RAM
 ↓
Output

3. What is Linux?

Answer

Linux is an open-source operating system kernel.

Common distributions:

Ubuntu
CentOS
Red Hat
Amazon Linux
Debian

Why Linux?

Secure
Stable
Free
Highly customizable
Most cloud servers use Linux

4. What is a Kernel?

Answer

Kernel is the core of the operating system.

Responsibilities:

Process management
Memory management
Hardware communication
Device drivers

Example:

Chrome requests memory.

Kernel decides:

How much RAM
Which CPU core
What permissions

5. What is a Process?

Answer

A process is a running instance of a program.

Example:

firefox

When Firefox starts:

Process ID assigned
Memory allocated
CPU assigned

Check processes:

ps -ef

top

6. What is PID?

Answer

PID = Process ID

Every running process gets a unique number.

Example:

ps -ef

Output:

root 1234 nginx

1234 is PID.

7. What is RAM?

Answer

RAM (Random Access Memory) is temporary memory used by running applications.

Example:

Application running:

Stored in RAM

Server reboot:

RAM contents disappear

8. Difference Between RAM and Disk

RAM	Disk
Temporary	Permanent
Fast	Slower
Lost after reboot	Survives reboot
Running programs	File storage

9. What is a File System?

Answer

File System organizes files and directories on storage.

Examples:

ext4
xfs
NTFS

Linux stores everything as files.

10. Linux Directory Structure

Question

Explain Linux file system hierarchy.

Answer

/
├── bin
├── etc
├── home
├── var
├── tmp
├── opt
├── usr

Important Directories

/etc

Configuration files

/etc/nginx/nginx.conf

/var

Logs

/var/log

/home

User files

/home/ec2-user

/tmp

Temporary files

/bin

System commands

ls
cp
mv

11. What is Troubleshooting?

Answer

Troubleshooting is a systematic process of finding and fixing issues.

Steps

Identify problem
Collect logs
Verify symptoms
Find root cause
Fix issue
Verify fix

12. Website Not Working. How Do You Troubleshoot?

Answer

Step 1

Check DNS

nslookup google.com

Step 2

Check connectivity

ping

Step 3

Check port

telnet hostname 80

Step 4

Check service

systemctl status nginx

Step 5

Check logs

journalctl

cat /var/log/nginx/error.log

13. What is Hardware?

Answer

Physical components of a computer.

Examples:

CPU
RAM
SSD
Motherboard
NIC

14. What is Software?

Answer

Programs that run on hardware.

Examples:

Linux
Windows
Chrome
Docker

15. CPU vs RAM

CPU

Brain of computer.

Executes instructions.

RAM

Working memory.

Stores active data.

16. What is a Server?

Answer

A server is a computer that provides services to other computers.

Examples:

Web Server
Database Server
DNS Server

17. What is AWS?

Interview Question

What is AWS?

Answer

AWS stands for Amazon Web Services.

Cloud platform providing:

Compute
Storage
Networking
Databases
Security

Benefits:

Pay as you go
Highly available
Scalable

18. What is a Region?

Answer

A Region is a geographical area containing multiple Availability Zones.

Examples:

us-east-1
us-east-2
eu-west-1

19. What is an Availability Zone?

Answer

Availability Zone (AZ) is one or more data centers inside a region.

Example:

us-east-1
├── us-east-1a
├── us-east-1b
├── us-east-1c

Applications are deployed across multiple AZs for high availability.

20. What is EC2?

Answer

EC2 = Elastic Compute Cloud

Virtual server in AWS.

Used to run:

Applications
Databases
Websites

Example:

Launch Linux EC2.

SSH into it.

Install nginx.

Host website.

21. What is EBS?

Answer

EBS = Elastic Block Store

Persistent storage attached to EC2.

Like a virtual hard drive.

Example:

EC2
  ↓
EBS Volume

If EC2 stops:

Data remains on EBS.

22. What is S3?

Answer

S3 = Simple Storage Service

Object storage.

Stores:

Images
Videos
Backups
Logs

Example:

bucket
 ├─ image.jpg
 ├─ video.mp4
 └─ logs.txt

Features:

Durable
Scalable
Cheap

23. What is ECS?

Answer

ECS = Elastic Container Service

AWS container orchestration service.

Runs Docker containers.

Components

Cluster
Task Definition
Service
Task

Flow:

Docker Image
     ↓
ECR
     ↓
ECS Task
     ↓
ECS Service

24. What is Lambda?

Answer

AWS Lambda is serverless compute.

You upload code.

AWS runs it.

No server management required.

Example:

API Gateway
      ↓
Lambda
      ↓
S3

25. What is API Gateway?

Answer

API Gateway exposes APIs to users.

Acts as front door for backend services.

Example:

User
 ↓
API Gateway
 ↓
Lambda
 ↓
Database

Benefits:

Authentication
Throttling
Monitoring

26. How Do Two Computers Communicate?

Answer

Example:

Laptop → Google Server

Step 1

Laptop gets IP address.

Example:

192.168.1.10

Step 2

DNS resolves domain.

google.com
↓
142.x.x.x

Step 3

TCP connection established.

3-Way Handshake:

SYN
SYN-ACK
ACK

Step 4

Data exchanged.

Step 5

Response returned.

27. Explain OSI Model

Answer

OSI has 7 layers.

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

Layer 7 Application

User applications.

Examples:

Chrome
Firefox

Protocols:

HTTP
HTTPS

Layer 6 Presentation

Encryption.

Examples:

Layer 5 Session

Maintains communication sessions.

Layer 4 Transport

Reliable communication.

Protocols:

Layer 3 Network

Routing.

Device:

Router

Protocol:

Layer 2 Data Link

MAC addresses.

Device:

Switch

Layer 1 Physical

Cables and signals.

Examples:

Fiber
Ethernet

28. Explain TCP 3-Way Handshake

Answer

Connection establishment:

Client → SYN
Server → SYN-ACK
Client → ACK

After this, data transfer begins.

29. What is DNS?

Answer

DNS converts domain names into IP addresses.

Example:

google.com
↓
142.250.x.x

Command:

nslookup google.com

30. Common Linux Commands Every DevOps Engineer Must Know

pwd
ls -la
cd
cp
mv
rm
mkdir
find
grep
cat
less
tail
head
chmod
chown
ps
top
df -h
du -sh
free -m
netstat
ss
curl
wget
systemctl
journalctl

These are the foundational interview questions for DevOps, Linux, Cloud, SRE, and AWS roles. A 6-year DevOps interview will often build on these basics and then move into Docker, Kubernetes, Terraform, CI/CD, VPCs, Load Balancers, Auto Scaling, IAM, monitoring, logging, and troubleshooting scenarios.

interview questions and answers

Aisalkyn Aidarova — Sat, 20 Jun 2026 00:03:32 +0000

If you're interviewing for a Senior DevOps Engineer (5–7 years), you should not only know definitions. You should understand why the technology exists, what problem it solves, how it works internally, and when to use it.

1. What is AWS?

Interview Question

What is AWS?

Answer

AWS (Amazon Web Services) is a cloud computing platform provided by Amazon Web Services.

Instead of buying physical servers, networking equipment, and storage, companies rent resources from AWS on demand.

AWS provides:

Compute (EC2, Lambda, ECS, EKS)
Storage (S3, EBS, EFS)
Networking (VPC, Route53, ELB)
Databases (RDS, DynamoDB)
Security (IAM, KMS, Secrets Manager)

Why Companies Use AWS

Traditional Infrastructure:

Buy Server
Install OS
Configure Network
Manage Hardware

AWS:

Create EC2
Deploy Application
Done

Benefits:

No hardware management
High availability
Pay as you go
Auto scaling
Global presence

2. What is an Operating System?

Interview Question

What is an Operating System?

Answer

An Operating System (OS) is software that sits between hardware and applications.

Without an OS:

Application
    ↓
Hardware

Application would need to control:

CPU
Memory
Disk
Network Card

directly.

With OS:

Application
      ↓
Operating System
      ↓
Hardware

Examples:

Linux
Windows
macOS

3. Linux Architecture

Interview Question

Explain Linux Architecture.

Answer

User
 ↓
Shell
 ↓
Kernel
 ↓
Hardware

Shell

Interface where users type commands.

Examples:

ls
pwd
cd

Popular shells:

Bash
Zsh
Sh

Kernel

Brain of Linux.

Responsibilities:

CPU scheduling
Memory management
Process management
Device communication

Hardware

Physical components:

CPU
RAM
SSD
Network Card

4. Hardware Components

Interview Question

Explain major hardware components.

CPU

Brain of computer.

Responsible for:

Executing instructions
Running applications

Check CPU:

lscpu

RAM

Temporary memory.

Stores:

Running processes
Application data

Check RAM:

free -h

SSD

Permanent storage.

Stores:

OS
Files
Applications

Check disk:

df -h

Network Interface Card (NIC)

Responsible for network communication.

Check:

ip addr

5. Linux Process Management

Interview Question

What is a Process?

Answer

A process is a running program.

Examples:

nginx
java
python
docker

View processes:

ps -ef

top

6. Systemd

Interview Question

What is systemd?

Answer

Systemd is Linux's service manager.

Used to:

Start services
Stop services
Restart services
Manage boot process

Examples:

systemctl start nginx
systemctl stop nginx
systemctl restart nginx

Check status:

systemctl status nginx

7. Journalctl

Interview Question

How do you check service logs?

Answer

journalctl -u nginx

Last 100 lines:

journalctl -u nginx -n 100

Live logs:

journalctl -f

8. Network Troubleshooting

Interview Question

User cannot access website. How do you troubleshoot?

Step 1: Verify DNS

nslookup google.com

dig google.com

Step 2: Verify Network

ping google.com

Step 3: Verify Route

traceroute google.com

Step 4: Verify Port

telnet website.com 443

nc -zv website.com 443

Step 5: Verify Listening Port

ss -tulnp

netstat -tulnp

Step 6: Check Firewall

iptables -L

ufw status

9. EC2

Interview Question

What is EC2?

Answer

Amazon EC2 is a virtual machine running inside AWS.

You choose:

CPU
RAM
Disk
OS

AWS creates server for you.

Example:

Ubuntu
4 vCPU
16GB RAM

10. EBS

Interview Question

What is EBS?

Answer

Amazon EBS is block storage attached to EC2.

Think:

EC2 = Computer
EBS = Hard Drive

Characteristics:

Persistent
Attached to one instance
Fast
Supports snapshots

Example:

EC2
 └── EBS Volume (100GB)

11. EFS

Interview Question

What is EFS?

Answer

Amazon EFS is a shared file system.

Multiple EC2 servers can mount same storage.

EC2-1
EC2-2
EC2-3
   ↓
EFS

Uses NFS protocol on:

Port 2049

EBS vs EFS

Feature	EBS	EFS
Shared	No	Yes
Multiple Servers	No	Yes
Protocol	Block	NFS
Use Case	Database	Shared Files

12. S3

Interview Question

What is S3?

Answer

Amazon S3 is object storage.

Stores:

Images
Videos
Backups
Logs

Structure:

Bucket
 ├── image.png
 ├── file.pdf
 └── backup.zip

Characteristics:

Unlimited storage
11 nines durability
Cheap

Common Use Cases

Log storage
Static websites
Backup storage
Data lake

13. Lambda

Interview Question

What is Lambda?

Answer

AWS Lambda runs code without managing servers.

Traditional:

EC2
Install OS
Patch Server
Run Code

Lambda:

Upload Code
Execute Function
Done

Triggers:

API Gateway
S3 Upload
EventBridge
SNS

Example

User uploads file:

S3 Upload
   ↓
Lambda Trigger
   ↓
Resize Image

14. API Gateway

Interview Question

What is API Gateway?

Answer

Amazon API Gateway is a front door for APIs.

Flow:

User
 ↓
API Gateway
 ↓
Lambda

Responsibilities:

Authentication
Authorization
Rate limiting
Routing

Example

GET /students
POST /students
DELETE /students

API Gateway routes requests.

15. Application Load Balancer (ALB)

Interview Question

What is ALB?

Answer

Application Load Balancer distributes traffic across multiple servers.

Without ALB:

10000 users
      ↓
Single Server

Server crashes.

With ALB:

10000 users
      ↓
ALB
   ↓    ↓
EC2-1 EC2-2

Traffic distributed.

Layer

Works at:

OSI Layer 7

HTTP/HTTPS.

Supports

Path routing
Host routing
SSL termination

Example:

/api → Backend
/images → Frontend

16. Auto Scaling Group (ASG)

Interview Question

What is ASG?

Answer

Amazon EC2 Auto Scaling automatically adds or removes EC2 instances.

Example:

Normal:

2 EC2
CPU 30%

Traffic spike:

CPU 90%

ASG launches:

4 EC2

Traffic drops:

Back to 2 EC2

ASG + ALB Together

Production architecture:

Users
   ↓
ALB
   ↓
Target Group
   ↓
Auto Scaling Group
   ↓
EC2 Instances

ALB distributes traffic.

ASG maintains healthy servers.

17. Senior DevOps Scenario Question

Interview Question

A website is down. How do you troubleshoot?

Answer

Check DNS

nslookup website.com

Check connectivity

ping website.com

Check load balancer health

ALB Target Group

Check EC2

systemctl status nginx

Check logs

journalctl -u nginx

Check disk

df -h

Check memory

free -h

Check CPU

top

Check listening ports

ss -tulnp

Check security groups and NACLs.

This step-by-step troubleshooting approach is what interviewers expect from a DevOps engineer with several years of experience.

interview questions

Aisalkyn Aidarova — Fri, 19 Jun 2026 00:03:18 +0000

This is a very large topic. For a DevOps/SRE interview, these are the most common questions with answers and explanations.

1. What is an Operating System (OS)?

Answer

An Operating System is software that manages hardware resources and provides services for applications.

Examples:

Linux
Windows
macOS

Responsibilities

Process management
Memory management
File management
User management
Network management
Device management

Real Example

When you open Chrome:

OS allocates RAM.
OS schedules CPU.
OS accesses files from disk.
OS handles network traffic.

2. What are the main Linux Components?

Answer

Linux consists of:

Kernel

Core of Linux.

Responsible for:

CPU scheduling
Memory management
Device drivers
Networking

Shell

Examples:

Bash
Zsh
Sh

Responsible for:

Executing commands

File System

Stores:

Files
Directories

System Libraries

Allow applications to communicate with the kernel.

User Space Applications

Examples:

nginx
docker
kubectl

3. Explain Linux Boot Process

Answer

BIOS/UEFI starts
GRUB bootloader loads
Linux kernel loads
systemd starts
Services start
Login prompt appears

4. What is CPU?

Answer

CPU = Central Processing Unit

It executes instructions.

Think of CPU as the brain of the computer.

Responsibilities

Calculations
Running applications
Scheduling processes

Check CPU

lscpu

top

htop

5. What is RAM?

Answer

RAM = Random Access Memory

Temporary storage used by running applications.

Example

Application running:

CPU processes data
RAM stores active data

Check RAM

free -h

top

vmstat

6. Difference Between RAM and Disk

RAM	Disk
Temporary	Permanent
Faster	Slower
Lost after reboot	Saved after reboot

7. What is a Process?

Answer

A process is a running program.

Example:

ps -ef

Show all processes.

8. What is a Thread?

Answer

A thread is a lightweight execution unit inside a process.

Example:

Google Chrome:

One process
Many threads

9. Linux Directory Structure

What is / ?

Root directory.

Important Directories

/etc

Configuration files

Examples:

/etc/passwd
/etc/hosts

/var

Logs

Examples:

/var/log

/home

User files

/tmp

Temporary files

/bin

Basic commands

/usr

Installed applications

/opt

Third-party applications

/dev

Devices

Example:

/dev/sda

/proc

Kernel information

10. What is a File?

Everything in Linux is treated as a file.

Examples:

Regular file
Directory
Device
Socket

Check:

ls -l

11. File Permissions

Example:

-rwxr-xr-x

Meaning

Owner:

rwx

Group:

r-x

Others:

r-x

Change permissions

chmod 755 file

12. Network Troubleshooting Questions

Check IP

ip a

Check Routing

ip route

Check DNS

nslookup google.com

dig google.com

Check Connectivity

ping google.com

Check Port

nc -zv host 443

Check Open Connections

ss -tulpn

Trace Network Path

traceroute google.com

13. What is DNS?

Answer

DNS converts:

google.com

142.250.x.x

Without DNS you would need to remember IP addresses.

14. TCP vs UDP

TCP

Reliable

Examples:

HTTPS
SSH

UDP

Faster

Examples:

DNS
Video streaming

15. What is AWS?

Answer

Amazon Web Services is a cloud platform that provides:

Compute
Storage
Networking
Security

Pay only for what you use.

16. What is EC2?

Answer

Amazon EC2 is a virtual machine in AWS.

Used for:

Applications
Databases
Containers

17. What is Elastic IP?

Answer

Static public IP address.

Used when:

Public IP must not change.

Example:

Bastion host
Web server

18. What is EBS?

Answer

Amazon EBS = Block Storage

Think:

Virtual hard drive attached to EC2.

Features

Persistent
Fast
Single AZ

19. What is EFS?

Answer

Amazon EFS = Shared File System

Many EC2 instances can mount the same storage.

Uses

Shared application files
Kubernetes persistent storage

20. EBS vs EFS

EBS	EFS
Block Storage	File Storage
One EC2	Many EC2
Single AZ	Multi-AZ
Faster	Shared

21. What is S3?

Answer

Amazon S3

Stores:

Images
Videos
Backups
Logs

Unlimited scale.

22. What is CloudFront?

Answer

Amazon CloudFront

CDN service.

Caches content close to users.

Benefits

Faster websites
Lower latency
DDoS protection

23. What is Load Balancer?

Answer

Distributes traffic among servers.

Example:

1000 users
      |
     ALB
   /     \
EC2     EC2

24. What is ALB?

Answer

Application Load Balancer

Works at:

HTTP
HTTPS

Can route:

/app
/api
/images

to different targets.

25. What is NLB?

Answer

Network Load Balancer

Works at:

Used for:

High performance
Millions of requests

26. ALB vs NLB

ALB	NLB
Layer 7	Layer 4
HTTP/HTTPS	TCP/UDP
Path Routing	No Path Routing
Web Apps	High-performance apps

27. What is Auto Scaling Group?

Answer

Automatically adds or removes EC2 instances.

Example:

CPU > 70%

2 EC2 → 4 EC2

Traffic decreases:

4 EC2 → 2 EC2

28. What is Reserved Instance?

Answer

Commit for:

1 year
3 years

Receive large discount.

Used for predictable workloads.

29. What is Spot Instance?

Answer

Unused AWS capacity.

Up to 90% cheaper.

Can be terminated anytime.

Best for:

Batch jobs
CI/CD
Testing

30. What is Dedicated Host?

Answer

Physical server dedicated only to one customer.

No other AWS customers share that hardware.

Used for:

Compliance
Licensing requirements

31. What is Security Group?

Answer

Virtual firewall for EC2.

Example:

Allow:

22 SSH
80 HTTP
443 HTTPS

Deny everything else.

32. What is VPC?

Answer

Virtual network in AWS.

Contains:

Subnets
Route tables
Security groups
EC2

33. What is NAT Gateway?

Answer

Allows private instances to access internet.

Internet cannot initiate connections to them.

34. What is Route Table?

Answer

Network map telling traffic where to go.

Example:

0.0.0.0/0
→ Internet Gateway

35. What is Internet Gateway?

Answer

Allows public subnet resources to access internet.

36. Production Troubleshooting Question

Interviewer:

Application is down. What do you check?

Answer

Step 1

Check DNS

nslookup app.company.com

Step 2

Check Load Balancer

Target healthy?

Step 3

Check EC2

systemctl status nginx

Step 4

Check Ports

ss -tulpn

Step 5

Check Logs

journalctl -xe

tail -f /var/log/nginx/error.log

Step 6

Check Resources

top
free -h
df -h

Step 7

Check Network

ping
curl
traceroute

37. Top Linux Commands Every DevOps Engineer Must Know

pwd
ls
cd
mkdir
rm
cp
mv
cat
less
head
tail
grep
find
chmod
chown
ps
top
htop
kill
df -h
du -sh
free -h
ip a
ip route
ping
curl
wget
dig
nslookup
systemctl
journalctl
ssh
scp
tar
gzip
unzip

These cover roughly 80–90% of the Linux, AWS, networking, and troubleshooting questions commonly asked in DevOps, SRE, Platform Engineer, and Cloud Engineer interviews.

DEV Community: Aisalkyn Aidarova

Docker Lab 3 – Docker Volumes (The Real Power of Docker)

Learning Objectives

Real DevOps Scenario

Today's Goal

Step 1 Create Project

Step 2 Create Website

Step 3 Pull Nginx Image

Step 4 Run Container Using Volume

Explain Every Option

docker run

-d

-p 8080:80

-v

$(pwd)

:

/usr/share/nginx/html

Architecture

Step 5 Check Running Container

Step 6 Open Browser

Step 7 Change Website

Step 8 Refresh Browser

Explain Why

Step 9 Verify Inside Container

Step 10 Delete Website

Why?

Step 11 Stop Container

Step 12 Remove Container

Verify

Key Difference

Lab 1

Lab 3

Why DevOps Engineers Use Volumes

Challenge Exercise

Docker Lab 2: Build and Run a Python Web Application in Docker

Goal

Real DevOps Scenario

Step 1: Create the Project Folder

Step 2: Create the Application

Step 3: Create Requirements File

Why do we need requirements.txt?

Step 4: Create Dockerfile

Explain Every Line

FROM

WORKDIR

COPY

RUN

COPY

EXPOSE

CMD

Step 5: Build Image

Step 6: Check Images

Step 7: Run Container

Step 8: Open Browser

Step 9: View Logs

Step 10: Enter the Container

Step 11: Stop and Remove

What Students Learned

Docker Lab 3: Multi-Container Application with Docker Compose

Goal

Real DevOps Scenario

Step 1: Create the Project

Step 2: Create index.html

Step 3: Create Dockerfile

Step 4: Create docker-compose.yml

Explain the Compose File

version

services

build

container_name

ports

Step 5: Start Everything

Step 6: Check Running Containers

Step 7: Open Browser

Step 8: View Logs

Step 9: Stop Everything

What Students Learned

Docker Lab: Run a Simple Website in a Container

Goal

Real DevOps Scenario

Why do we need `requirements.txt`?

Step 2: Create `index.html`

Step 4: Create `docker-compose.yml`