Installs Docker + Compose, sets a docker group and a service

install_docker.sh

#!/bin/bash

# Exit immediately if a command exits with a non-zero status.
set -e

echo "🚀 Starting Docker installation..."

# 1. Set up Docker's apt repository
echo "🔧 Setting up Docker's apt repository..."
sudo apt-get update
sudo apt-get install -y ca-certificates curl gnupg

sudo install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
sudo chmod a+r /etc/apt/keyrings/docker.gpg

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

# 2. Install Docker Engine
echo "⚙️ Installing Docker Engine, CLI, Containerd, Buildx, and Compose plugin..."
sudo apt-get update
sudo apt-get install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

# 3. Post-installation steps
echo "🔧 Performing post-installation steps..."

# Create the docker group (if it doesn't already exist)
if ! getent group docker > /dev/null; then
    sudo groupadd docker
    echo "Created 'docker' group."
else
    echo "'docker' group already exists."
fi

# Add the current user to the docker group
sudo usermod -aG docker $USER
echo "👤 Added user '$USER' to the 'docker' group. You'll need to log out and log back in for this to take effect."

# Configure Docker to start on boot with systemd
sudo systemctl enable docker.service
sudo systemctl enable containerd.service
echo "🔌 Configured Docker to start on boot."

echo "✅ Docker installation and basic configuration complete!"
echo "🎉 To use Docker without sudo, please log out and log back in, or run 'newgrp docker' in your current terminal."
echo "💡 You can verify the installation by running: docker run hello-world"