🐳 Installing Docker on Linux (Easy Step-by-Step Guide)

Docker lets you run applications in isolated containers, making setup, deployment, and testing much easier. This guide shows the recommended, official way to install Docker on a Linux PC.

The instructions work for Ubuntu, Linux Mint, Debian, and other Debian-based distributions.

---

✅ Prerequisites

Before you start, make sure:

• You are running a 64-bit Linux system
• You have a user with sudo privileges
• Your system is up to date

Update your system:

sudo apt update && sudo apt upgrade -y

---

🧹 Step 1: Remove Old Docker Versions (If Any)

If Docker was previously installed, remove old packages to avoid conflicts:

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

---

🔑 Step 2: Add Docker’s Official GPG Key

Create a keyring directory:

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

Download and install Docker’s GPG key:

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

Set correct permissions:

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

---

📦 Step 3: Add Docker Repository

Add the official Docker repository:

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

Update package lists:

sudo apt update

---

🐋 Step 4: Install Docker Engine

Install Docker and related tools:

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

---

▶️ Step 5: Start and Enable Docker

Start Docker now:

sudo systemctl start docker

Enable Docker at boot:

sudo systemctl enable docker

Check status:

systemctl status docker

---

👤 Step 6: Run Docker Without sudo (Recommended)

Add your user to the docker group:

sudo usermod -aG docker $USER

⚠️ Important: Log out and log back in (or reboot) for this to take effect.

---

🧪 Step 7: Test the Installation

Run the official test container:

docker run hello-world

If you see a success message, Docker is working correctly 🎉

---

🔧 Common Issue: Permission Denied on /var/run/docker.sock

If you see:

permission denied while trying to connect to the Docker daemon

Fix it with:

sudo usermod -aG docker $USER
logout

Then log back in and try again.

---

📎 Appendix: Installing Docker on Windows

Option 1: Docker Desktop (Recommended)

1. Enable WSL2 in Windows
   Open PowerShell (Admin): wsl --install
2. Reboot when prompted
3. Download Docker Desktop for Windows from Docker’s website
4. During setup:
   • Enable “Use WSL 2 backend”
   • Allow installer to add required components
5. After installation, open Docker Desktop
6. Test in PowerShell or WSL: docker run hello-world

---

Option 2: Using Docker Inside WSL (Advanced)

• Install Ubuntu via Microsoft Store
• Follow the Linux instructions above inside WSL
• Ensure Docker Desktop is not running simultaneously

---

✅ Summary

• Linux: Install Docker via the official Docker repository
• Avoid Snap/Flatpak Docker installs for production use
• Add your user to the docker group to avoid sudo
• Windows users should use Docker Desktop + WSL2