Dock

Docker Installation and Basic Commands Using Ubuntu

By Db4Cloud Technologies

Introduction

Containerization has become an essential technology in modern cloud and DevOps environments. Docker allows developers to package applications and dependencies into containers that can run consistently across multiple environments.

In this guide, we will explain how to install Docker on Ubuntu and run basic Docker commands.

Step 1: Update Ubuntu System

Before installing Docker, update the package list.

sudo apt update

sudo apt upgrade -y

This ensures Ubuntu has the latest package versions.

Step 2: Install Required Packages

sudo apt install apt-transport-https ca-certificates curl software-properties-common -y

These packages allow Ubuntu to download Docker from secure repositories.

Step 3: Add Docker GPG Key

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

This command adds Docker’s official security key to the system.

Step 4: Add Docker Repository

sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu focal stable"

This adds the official Docker repository.

Step 5: Install Docker

sudo apt update

sudo apt install docker-ce -y

This installs the Docker Community Edition.

Step 6: Check Docker Status

sudo systemctl status docker

If Docker is running correctly, you will see Active (running).

Step 7: Check Docker Version

docker --version

Example output:

Docker version 24.0.6

Step 8: Run Docker Without sudo (Optional)

sudo usermod -aG docker $USER

Then log out and log in again.

This allows running Docker commands without sudo.

Basic Docker Commands

1. Test Docker Installation

docker run hello-world

Docker downloads a test image and runs it.

2. Download an Image

docker pull ubuntu

This downloads the Ubuntu image from Docker Hub.

3. List Docker Images

docker images

Shows all downloaded images.

Example output:

REPOSITORY TAG IMAGE ID

ubuntu latest abc123

nginx latest def456

4. Run Ubuntu Container

docker run -it ubuntu

Explanation:

OptionMeaning-iInteractive-tTerminal

Now you are inside the Ubuntu container.

5. List Running Containers

docker ps

6. List All Containers

docker ps -a

Shows both running and stopped containers.

7. Stop a Container

docker stop container_id

Example:

docker stop 7ab45cd

8. Remove Container

docker rm container_id

Deletes the container.

9. Remove Image

docker rmi image_id

Deletes the Docker image.

Example: Run Nginx Web Server

docker pull nginx

Run the container:

docker run -d -p 8080:80 nginx

Explanation:

OptionMeaning-dRun in background-pPort mapping8080:80Host port → Container port

Now open browser:

http://localhost:8080

You will see the Nginx web server page.

Docker in DevOps at Db4Cloud Technologies

At Db4Cloud Technologies, Docker is used for:

Cloud-native applications

DevOps CI/CD pipelines

Microservices architecture

Kubernetes deployments

Infrastructure automation

Docker helps our engineers deliver scalable, reliable, and automated cloud solutions for global customers.

Conclusion

Docker simplifies application deployment by creating portable containers. With Ubuntu, Docker installation and management become straightforward, making it ideal for developers and DevOps engineers.

Organizations adopting Docker gain faster deployments, consistent environments, and scalable infrastructure.