Ansible script to install rbenv. Intended for CentOS images.

rbenv.yml

---
# file ruby.yml
- hosts: all
  gather_facts: false
  sudo: true

  vars:
    # Where to install rbenv
    - rbenv_root: /usr/local/rbenv
    # The version of Ruby to install
    - ruby_version: 1.9.3-p448
    # The group to give all rbenv permission to
    - group: rbenv
    # Environment variables to help call rbenv while sudo
    - rbenv_env: RBENV_ROOT=$rbenv_root PATH=/usr/local/bin:$rbenv_root/shims:$rbenv_root/bin:$PATH
    # Essentially an alias for the binary
    - rbenv_bin: $rbenv_env rbenv

  tasks:
    - name: rbenv | install build depends
      yum: name=$item state=present
      with_items:
        - gcc-c++ 
        - patch 
        - readline 
        - readline-devel
        - zlib
        - zlib-devel
        - libyaml-devel
        - libffi-devel
        - openssl-devel
        - make
        - bzip2
        - autoconf
        - automake
        - libtool
        - bison
        - git-core

    - name: rbenv | create rbenv group
      group: state=present name=$group

    - name: rbenv | update rbenv repo
      git: repo=git://github.com/sstephenson/rbenv.git dest=$rbenv_root version=v0.4.0

    - name: rbenv | add rbenv to path
      file: path=/usr/local/bin/rbenv src=${rbenv_root}/bin/rbenv state=link

    - name: rbenv | alter permissions
      file: group=$group mode=0775 recurse=yes state=directory path=${rbenv_root}

    - name: rbenv | add rbenv initialization to profile
      template: src=templates/rbenv.sh.j2 dest=/etc/profile.d/rbenv.sh owner=root group=$group mode=0775

    - name: rbenv | check ruby-build installed
      command: test -x /usr/local/bin/ruby-build
      register: rbuild_present
      ignore_errors: True

    - name: rbenv | create temporary directory
      command: mktemp -d
      register: tempdir
      when: rbuild_present | failed

    - name: rbenv | clone ruby-build repo
      git: repo=git://github.com/sstephenson/ruby-build.git dest=${tempdir.stdout}/ruby-build
      when: rbuild_present|failed

    - name: rbenv | install ruby-build
      command: ./install.sh chdir=${tempdir.stdout}/ruby-build
      when: rbuild_present|failed

    - name: rbenv | remove temporary directory
      file: path=${tempdir.stdout} state=absent
      when: rbuild_present|failed

    - name: rbenv | check ruby $ruby_version installed
      shell: $rbenv_bin versions | grep $ruby_version
      register: ruby_installed
      ignore_errors: yes

    - name: rbenv | install ruby $ruby_version
      sudo: true
      shell: $rbenv_bin install $ruby_version
      when: ruby_installed|failed

    - name: rbenv | set global ruby $ruby_version
      shell: $rbenv_bin global $ruby_version
      when: ruby_installed|failed

    - name: rbenv | rehash
      shell: $rbenv_bin rehash
      when: ruby_installed|failed

    - name: rbenv | set gemrc
      copy: src=files/gemrc dest=/root/.gemrc owner=root group=root mode=0644

Note: you need a template file:

templates/rbenv.sh.j2

export RBENV_ROOT="{{ rbenv_root }}"
export PATH="/usr/local/bin:$RBENV_ROOT/shims:$RBENV_ROOT/bin:$PATH"

eval "$(rbenv init -)"