Debian¶

Lab Info

Estimated Time: 60–90 minutes Audience: Beginners Tools used: RHEL 9 / CentOS Stream, Ubuntu 22.04 / Debian 11, Docker CE (Community Edition)

Learning Objectives

Install Docker on Linux systems.
Understand how to start and enable Docker service.
Run a test container to verify installation.
Launch a simple Nginx container to see Docker in action.
Visualize Docker workflow in DevOps.

Install Docker¶

RHEL / CentOSUbuntu / Debian

Step 1: Update system¶

sudo dnf update -y

Explanation: Updates your system packages for stability and compatibility.

Step 2: Remove old versions (if any)¶

sudo dnf remove docker \
                docker-client \
                docker-client-latest \
                docker-common \
                docker-latest \
                docker-latest-logrotate \
                docker-logrotate \
                docker-engine

Explanation: Removes old Docker versions that may cause conflicts.

Step 3: Enable Docker CE repository¶

sudo dnf config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

Explanation: Docker CE is not in RHEL/CentOS base repos. This command adds Docker’s official repo.

Step 4: Install Docker CE¶

sudo dnf install -y docker-ce docker-ce-cli containerd.io docker-compose-plugin

Explanation: Installs Docker Engine, CLI, container runtime, and Docker Compose plugin.

Step 5: Start and enable Docker service¶

sudo systemctl start docker
sudo systemctl enable docker
sudo systemctl status docker

Explanation: Starts Docker now and ensures it starts on boot.

Step 6: Verify installation¶

sudo docker run hello-world

Explanation: Runs a test image from Docker Hub. If successful, Docker is working.

Step 7: Run an Nginx container¶

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

Visit: http://<your-server-ip>:8080

Explanation: Launches an Nginx web server container. Port 8080 on your host maps to container’s port 80.

Step 1: Update system¶

sudo apt update
sudo apt upgrade -y

Explanation: Updates package lists and upgrades existing packages.

Step 2: Remove old versions¶

sudo apt remove docker docker-engine docker.io containerd runc

Explanation: Ensures no legacy Docker is present.

Step 3: Install required packages¶

sudo apt install -y ca-certificates curl gnupg lsb-release

Explanation: These tools allow adding secure repositories and managing keys.

Step 4: Add Docker’s official GPG key¶

sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg

Explanation: Adds Docker’s signing key to verify package integrity.

Step 5: Set up repository¶

echo \
"deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] \
https://download.docker.com/linux/ubuntu \
$(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Explanation: Adds Docker’s official repo to apt sources.

Step 6: Install Docker CE¶

sudo apt update
sudo apt install -y docker-ce docker-ce-cli containerd.io docker-compose-plugin

Explanation: Installs Docker engine, CLI, container runtime, and Compose plugin.

Step 7: Start and enable Docker service¶

sudo systemctl start docker
sudo systemctl enable docker
sudo systemctl status docker

Explanation: Starts Docker now and on future boots.

Step 8: Verify installation¶

sudo docker run hello-world

Explanation: Confirms Docker can pull images from Docker Hub and run containers.

Step 9: Run an Nginx container¶

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

Visit: http://<your-server-ip>:8080

Explanation: Runs a web server inside a container and exposes it.

Visualization of what happened¶

Docker Engine: core service managing containers.
Images: pre-packaged software (like templates).
Containers: running instances of images.
Docker Hub: central registry where images come from.
hello-world: confirms Docker works.
nginx: practical example of running an application container.