# Installation

This guide explains how to install Docker Engine using the official Docker repository.

## Prerequisites

- Root or `sudo` privileges  
- Supported OS: Debian 10/11/12 or Ubuntu 20.04/22.04

---

## 1. Remove old versions (if any)

```bash
sudo apt-get remove docker docker-engine docker.io containerd runc
```

---

## 2. Set up the repository

### 2.1 Install required packages

```bash
sudo apt-get update
sudo apt-get install -y \
    ca-certificates \
    curl \
    gnupg \
    lsb-release
```

### 2.2 Add Docker’s official GPG key

```bash
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/$(. /etc/os-release && echo "$ID")/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
```

### 2.3 Set up the Docker repository

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

---

## 3. Install Docker Engine

```bash
sudo apt-get update
sudo apt-get install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
```

---

## 4. Enable and start the Docker service

```bash
sudo systemctl enable docker
sudo systemctl start docker
```

---

## 5. Verify installation

```bash
sudo docker run hello-world
```

---

## Optional: Add your user to the `docker` group

```bash
sudo usermod -aG docker $USER
newgrp docker
```

---

## References

- https://docs.docker.com/engine/install/