Install rbenv and ruby-build to Amazon Linux (cloud-init).

README.md

1. run user-data.sh
2. run install-ruby.sh.

install-ruby.sh

git clone git://github.com/sstephenson/rbenv.git ~/.rbenv
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(rbenv init -)"' >> ~/.bashrc
source ~/.bashrc

asudo apt-get install libssl-dev

ruby-build install 1.9.3-p194 --with-openssl-dir=$(which openssl | sed 's/\/bin.*$//')
rbenv global 1.9.3-p194

user-data.sh

#!/bin/sh

sudo apt-get install gcc make
sudo apt-get install zlib1g-dev libreadline-dev
git clone git://github.com/sstephenson/ruby-build.git /tmp/ruby-build
cd /tmp/ruby-build
./install.sh