Install Docker Engine on Linux

This guide explains how to install Docker Engine on a Linux system. Docker Engine is a prerequisite for installing NiralOS EDGE.

Supported Distributions #

This guide uses Ubuntu as the reference distribution. The steps are applicable to

Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and other Debian-based distributions.

Prerequisites #

Before installing Docker Engine, ensure that:

• You have a supported Linux distribution. 
• You have a user account with sudo privileges. 
• The system has an active Internet connection. 
• Any older Docker packages have been removed (if previously installed).

Step 1. Update the Package Index #

Open a terminal and update the package repository.

sudo apt update

Step 2. Install Required Packages #

Install the packages required to add Docker’s official repository.

sudo apt install -y ca-certificates curl gnupg

Step 3. Create the Docker Keyring Directory #

Create the directory used to store Docker’s GPG key.

sudo install -m 0755 -d /etc/apt/keyrings

Step 4. Download Docker’s GPG Key #

Download and save Docker’s official signing key.

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

Set the correct permissions on the key.

sudo chmod a+r /etc/apt/keyrings/docker.gpg

Step 5. Add the Docker Repository #

Add Docker’s official APT repository to your system.

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

Step 6. Refresh Package Information #

Update the package index to include Docker packages.

sudo apt update

Step 7: Install Docker Engine #

Install Docker Engine along with the required components.

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

Step 8: Verify Docker Service #

Check whether the Docker service is running.

sudo systemctl status docker

A successful installation should show the service as:

Active: active (running)

Press Q to exit the status screen.

Step 9: Start Docker (If Required) #

If Docker is not already running, start the service.

sudo systemctl start docker

Enable Docker to start automatically on system boot.

sudo systemctl enable docker

Step 10: Allow the Current User to Run Docker #

Add your user account to the docker group.

sudo usermod -aG docker $USER

Apply the new group membership without logging out.

newgrp docker

Note: If the new group membership is not applied immediately, log out and log back into your Linux session.

Step 11: Verify Docker Installation #

Check the installed Docker version.

docker --version

Example output: Docker version 28.x.x

Step 12: Verify Docker Engine #

Display Docker system information.

docker info

The command should complete without permission errors.

Step 13: Test Docker #

Run Docker’s official test container.

docker run hello-world

A successful installation displays a message similar to: Hello from Docker!

This message shows that your installation appears to be working correctly.

Step 14: Verify User Permissions #

Run the following command without using sudo.

docker ps

If an empty container list is displayed, your user has permission to access Docker Engine.

Example:

CONTAINER ID   IMAGE   COMMAND   CREATED   STATUS   PORTS   NAMES

Installation Complete #

Docker Engine is now installed and ready for use.

You can proceed with the NiralOS EDGE interactive installer:

curl -fsSL https://niraledge.com/install.sh | bash

Troubleshooting #

Permission Denied While Running Docker

If you receive a permission error when executing Docker commands:

• Verify that your user has been added to the docker group. 
• Log out and log back in, or run: 

newgrp docker

Docker Service Is Not Running #

Check the Docker service status.

sudo systemctl status docker

If necessary, start the service.

sudo systemctl start docker

Docker Command Not Found #

If the docker command is not recognized:

• Verify that Docker Engine was installed successfully. 
• Refresh the package index and reinstall Docker if required. 
• Open a new terminal session and run: 

docker --version

Verify Installation #

The following commands should all execute successfully:

docker --version

docker info

docker run hello-world

docker ps