Configure an AWS EC2 instance running Amazon Linux 2023 to deploy Rails apps using Kamal (Docker)

aws-amazon-linux-al2023-ec2-instance-setup-for-rails-docker-kamal-deployment.sh

#!/bin/bash

# This scrips takes a clean AWS Amazon Linux 2023 AMI and installs and configures
# everything needed to deploy a Rails app to it using Kamal.
# The resulting state is a clean instance ready to accept Kamal (Dockerized) apps.


# --- AESTHETICS ---

# Define the color code for green for echo messages
GREEN='\033[0;32m'

# Define the escape sequence for the alien emoji (U+1F47D)
ALIEN='\xF0\x9F\x91\xBD'

# Define the variable for resetting the color back to the default
NC='\033[0m'


# --- CONFIG SCRIPT STARTS ---

# Update package list and install Docker
echo -e "${GREEN}${ALIEN} Installing Docker and starting the Docker service...${NC}"
sudo dnf update -y
sudo dnf install -y docker --allowerasing
sudo systemctl start docker
echo -e "${GREEN}${ALIEN} Adding rails to the docker group and configuring the right Docker permissions...${NC}"
sudo chown root:docker /var/run/docker.sock
# Add current user to the docker group
sudo usermod -a -G docker $USER
# Update the group membership for the docker group - This will log us into a new shell session with the updated group membership.
newgrp docker
echo -e "${GREEN}${ALIEN} Restarting the Docker service...${NC}"
sudo systemctl restart docker

# crontab does not come installed by default in AL2023 (wtf?)
# echo -e "${GREEN}${ALIEN} Installing crontab to run scheduled background jobs...${NC}"
# sudo dnf install -y cronie
# sudo systemctl enable crond.service
# sudo systemctl start crond.service

# Delete previous command history so we leave the AMI in a clean state
history -c

echo -e "${GREEN}${ALIEN} Amazon Linux 2023 machine initial setup for Kamal deployments completed successfully.${NC}"