For some on-going projects I need to switch to different versions of ruby. Although there exist many step-by-step instructions on installing and configuring rvm for most Linux distros, there aren't many focused on Alpine "daily drivers".

So this post is more or less a helpful document for my future self. If it happens to help others then that's an added bonus!

Simple Setup

Make sure you have the basic packages first:

apk update
apk add curl gcc gnupg gpg dirmngr procps musl-dev linux-headers zlib zlib-dev openssl openssl-dev libssl1.1

Next download the latest stable version of rvm from Github, unpack it, place it in the proper user directory (~/.rvm) and install any required libs:

curl -sSL -o rvm-stable.tar.gz
echo 'export rvm_prefix="$HOME"' > ~/.rvmrc
echo 'export rvm_path="$HOME/.rvm"' >> ~/.rvmrc
mkdir rvm && cd rvm
tar --strip-components=1 -xzf ../rvm-stable.tar.gz
./install --auto-dotfiles --autolibs=0

Now we can remove everything and properly link to rvm:

cd ../ && rm -rf rvm-stable stable.tar.gz rvm
source ~/.rvm/scripts/rvm

Note: If you plan to work with bundler be sure to do the following before installing ruby versions via rvm:

rvm pkg install openssl
rvm pkg install libyaml

Now you can freely install any version of Ruby that you desire!

rvm install ruby-X.X.X