Programming

I needed to run some Ruby-code in my Fedora-box, but the RPM-packaged version wasn't a decent or recent one. Since it is standard procedure and native to Ruby programming language to use Ruby version manager (or RVM), it also opens immense possibilities of running any existing Ruby version in same machine without the versions colliding with each other, this is definitely something that people need to know how to do.

There is plenty of good information about this in the net, for example How to Install Ruby 2.1.2 on CentOS & RHEL using RVM. However, the definite source is of course Installing RVM manual at RVM.io.

When it comes to multi-user installations, docs say "For server administrators - For an installation usable by all users on the system - This also used to be called the System-Wide Install. Using this type of installation without knowledge how umask works is a big security risk". RVM has a very simple filesystem permission -based security model, which will collapes if umask is not set correctly in multi-user mode. However, the worst-case scenarios include some gems have incorrect permissions set and only the user how installed it can un-install. Ultimate worst-case scenario is, that people not belogning to rvm-group can install and un-install modules. In a system-wide setup other people tampering with critical resources can be fatal, hence the obligatory warnings.

My case is much simpler, I need the same stuff for myself to develop with and for the system to run with. That's how I know I develop, test and run the same libraries. I wouldn't dream on sharing the stuff with other persons and calling that secure.

Back to setup of my RVM, current ruby version information:

$ ruby -v
ruby 2.0.0p353 (2013-11-22 revision 43784) [x86_64-linux]

To start the installation, a simple one-liner will do:

$ curl -sSL http://get.rvm.io | sudo bash -s stable -- --ignore-dotfiles

It will download the latest stable installer bash-script and immediately execute it with flag not to use user's own files. This is more suitable for machine-wide mode. The really important thing is to use sudo. Installation will fail to setup correctly, if doing it as root. Another security warning here: you will be trusting blindly on something you downloaded from the web. Hey! They call it open-source.

The installation will work only on Bourne shells. I'd recommend using Bash with all RVM-operations. The installer will say something like this:

Downloading https://github.com/rvm/rvm/archive/master.tar.gz
Creating group 'rvm'

Installing RVM to /usr/local/rvm/
Installation of RVM in /usr/local/rvm/ is almost complete:

First you need to add all users that will be using rvm to 'rvm' group,
and logout - login again, anyone using rvm will be operating with `umask u=rwx,g=rwx,o=rx`.

To start using RVM you need to run `source /etc/profile.d/rvm.sh`
in all your open shell windows, in rare cases you need to reopen all shell windows.

# Thank you for using RVM!
# We sincerely hope that RVM helps to make your life easier and more enjoyable!!!
#
# ~Wayne, Michal & team.

In case of problems: http://rvm.io/help and https://twitter.com/rvm_io

If your system didn't have an user group called rvm, it does now. As the instructions say, it's your task now to assign users to that group. You can do it like this:

$ getent group rvm
rvm:x:983:

Your group ID will change, of course. Add your user to this new group like this (I'm doing it as root, sudo will do the trick also):

# usermod -a -G rvm joeuser
# getent group rvm
rvm:x:983:joeuser

Yet again, the instructions above say, that this addition will NOT take effect until one of these happens:

1. User logs in. If you're adding yourself, log out first.
2. newgrp-command is issued, newgrp(1) - Linux man page

RVM installer will add a file into /etc/profile.d/ to do some settings at login:

-rwxr-xr-x. 1 root root 1203 Nov 23 19:39 /etc/profile.d/rvm.sh

If you need to have the settings in effect, all you need to do is source it:

$ source /etc/profile.d/rvm.sh

Anyway, now the rig is ready, we only need an installed Ruby version to get the ball rolling. To get an idea what's out there, get a list of all available Rubies there are:

$ rvm list known
# MRI Rubies
[ruby-]1.8.6[-p420]
[ruby-]1.8.7[-head] # security released on head
[ruby-]1.9.1[-p431]
[ruby-]1.9.2[-p330]
[ruby-]1.9.3[-p551]
[ruby-]2.0.0[-p647]
[ruby-]2.1[.7]
[ruby-]2.2[.3]
[ruby-]2.2-head
ruby-head

I'm urging to go for the install, but my first install attempt stalled on some missing libraries. There was a prompt asking for my password, but I chose not to enter my personal password to a script. So:

# yum install libyaml-devel readline-devel libffi-devel sqlite-devel

When those landed, let's go for an install:

$ rvm install ruby-2.1.7

The installer will output a lot, some of it is:

Searching for binary rubies, this might take some time.
No binary rubies available for: fedora/20/x86_64/ruby-2.1.7.
Continuing with compilation. Please read 'rvm help mount'
to get more information on binary rubies.
Checking requirements for fedora.
Requirements installation successful.
Installing Ruby from source to: /usr/local/rvm/rubies/ruby-2.1.7,
this may take a while depending on your cpu(s)...
ruby-2.1.7 - #downloading ruby-2.1.7,
this may take a while depending on your connection...
ruby-2.1.7 - #extracting ruby-2.1.7 to /usr/local/rvm/src/ruby-2.1.7....
ruby-2.1.7 - #configuring...
ruby-2.1.7 - #post-configuration..
ruby-2.1.7 - #compiling...
ruby-2.1.7 - #installing...
ruby-2.1.7 - #making binaries executable..
ruby-2.1.7 - #downloading rubygems-2.4.8
ruby-2.1.7 - #extracting rubygems-2.4.8....
ruby-2.1.7 - #removing old rubygems.........
ruby-2.1.7 - #installing rubygems-2.4.8...
ruby-2.1.7 - #gemset created /usr/local/rvm/gems/ruby-2.1.7@global
ruby-2.1.7 - #importing gemset /usr/local/rvm/gemsets/global.gems...
ruby-2.1.7 - #generating global wrappers........
ruby-2.1.7 - #gemset created /usr/local/rvm/gems/ruby-2.1.7
ruby-2.1.7 - #importing gemsetfile /usr/local/rvm/gemsets/default.gems
evaluated to empty gem list
ruby-2.1.7 - #generating default wrappers........
ruby-2.1.7 - #adjusting #shebangs for (gem irb erb ri rdoc testrb rake).
Install of ruby-2.1.7 - #complete
Ruby was built without documentation,
to build it run: rvm docs generate-ri

But ultimately, you're good to go:

$ ruby -v
ruby 2.1.7p400 (2015-08-18 revision 51632) [x86_64-linux]

To get back to my original task, I installed a gem:

$ gem install davclient
Fetching: davclient-0.0.8.gem (100%)
Successfully installed davclient-0.0.8
Parsing documentation for davclient-0.0.8
Installing ri documentation for davclient-0.0.8
Done installing documentation for davclient after 0 seconds
1 gem installed

That's it! Everything is ready.