Objective

In this lab, readers will:

• Verify Docker Desktop operation

• Download Docker images

• Create and manage containers

• Understand ephemeral container storage

• Create and use Docker volumes

• Explore persistent storage

• Run a containerized web server

• Relate Docker storage concepts to cloud storage technologies

By the end of this lab, readers will understand why persistent storage is important for containers and how Docker volumes work.

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Background

Containers are lightweight environments that package applications and their dependencies.

Unlike virtual machines, containers share the host operating system kernel and can start within seconds.

One important concept in containerized environments is storage.

Data stored inside a container may be lost if the container is removed. To preserve data, Docker provides persistent storage mechanisms known as volumes.

This concept is similar to cloud block storage services such as:

• AWS Elastic Block Store (EBS)

• Azure Managed Disks

• Google Persistent Disk

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Part 1 – Verify Docker Desktop

Launch:

Docker Desktop

Wait until the status shows:

Engine running

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Part 2 – Open PowerShell

Open:

Start
 → PowerShell

Verify Docker:

docker version

Expected result:

Client:
 Version: xx.x

Server:
 Version: xx.x

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Part 3 – Verify Docker Engine

Display running containers:

docker ps

Expected output:

CONTAINER ID   IMAGE   COMMAND   STATUS

No containers are running yet.

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Part 4 – Run Your First Container

Execute:

docker run hello-world

Docker automatically:

1. Downloads the image

2. Creates a container

3. Runs the application

4. Stops the container

Expected output:

Hello from Docker!

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Part 5 – Explore Docker Images

Display downloaded images:

docker images

Example:

REPOSITORY      TAG
hello-world     latest

Discussion:

An image is a template used to create containers.

Examples:

• Windows ISO

• Virtual machine template

• Docker image

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Part 6 – Download Ubuntu Image

Download Ubuntu:

docker pull ubuntu

Verify:

docker images

Ubuntu should now appear in the image list.

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Part 7 – Start an Ubuntu Container

Launch Ubuntu interactively:

docker run -it ubuntu bash

You are now inside a Linux environment.

Verify:

whoami

Expected:

root

Check operating system:

cat /etc/os-release

Exit container:

exit

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Part 8 – Demonstrate Ephemeral Storage

Start a temporary Ubuntu container:

docker run -it ubuntu bash

Create a file:

echo "Temporary Data" > temp.txt

Verify:

cat temp.txt

Exit:

exit

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Part 9 – Create Another Ubuntu Container

Launch a completely new container:

docker run -it ubuntu bash

Check for the file:

cat temp.txt

Expected:

cat: temp.txt: No such file or directory

Exit:

exit

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Discussion

Why did the file disappear?

Because each new container starts with a fresh writable layer.

This storage is called:

Ephemeral Storage

Data stored only inside the container is temporary.

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Part 10 – Create a Docker Volume

Create a persistent volume:

docker volume create cloudplus-volume

Verify:

docker volume ls

Expected:

DRIVER    VOLUME NAME
local     cloudplus-volume

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Part 11 – Verify Empty Volume

Mount the volume into a container:

docker run -it -v cloudplus-volume:/data ubuntu bash

Check contents:

ls /data

Output:

The volume is empty because it has just been created.

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Part 12 – Store Data in the Volume

Inside the same container:

echo "Persistent Storage" > /data/storage.txt

Verify:

cat /data/storage.txt

Expected:

Persistent Storage

Exit:

exit

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Part 13 – Verify Persistence

Launch a completely new container using the same volume:

docker run -it -v cloudplus-volume:/data ubuntu bash

Check contents:

cat /data/storage.txt

Expected:

Persistent Storage

The file still exists.

Exit:

exit

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Discussion

What changed?

The container changed.

The volume remained.

This demonstrates persistent storage.

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Part 14 – Inspect the Volume

Display volume information:

docker volume inspect cloudplus-volume

Observe:

Mountpoint

This location stores the actual data.

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Part 15 – Run a Web Server

Download and run Nginx:

docker run -d --name webserver -p 8080:80 nginx

Verify:

docker ps

Expected:

webserver

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Part 16 – Access the Web Server

Open a browser.

Browse to:

http://localhost:8080

You should see:

Welcome to nginx!

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Discussion

Docker is mapping:

Host Port 8080
        ↓
Container Port 80

This is similar to exposing services in cloud environments.

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Part 17 – Explore Docker Desktop

Open Docker Desktop.

Observe:

Images

• hello-world

• ubuntu

• nginx

Containers

• Running containers

• Stopped containers

Volumes

• cloudplus-volume

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Part 18 – Examine Docker Storage Usage

Display storage consumption:

docker system df

Example:

TYPE            TOTAL
Images
Containers
Volumes
Build Cache

Observe how Docker consumes storage space.

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Part 19 – Cleanup

Stop Nginx:

docker stop webserver

Remove container:

docker rm webserver

Remove volume:

docker volume rm cloudplus-volume

Verify:

docker volume ls

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Reflection Questions

1. What is a Docker image?

2. What is a Docker container?

3. What is ephemeral storage?

4. What is a Docker volume?

5. Why did temp.txt disappear?

6. Why did storage.txt remain?

7. How is a Docker volume similar to AWS EBS?

8. Why is persistent storage important for databases?

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Learning Outcomes

After completing this lab, readers will be able to:

• Run Docker containers

• Download Docker images

• Understand container lifecycle

• Demonstrate ephemeral storage

• Create Docker volumes

• Demonstrate persistent storage

• Configure container port mappings

• Explore Docker Desktop resources

• Relate Docker storage concepts to cloud storage technologies