Failed to install mysql2 gem on Ubuntu 14 - mysql

Question

I'm running Ubuntu 14 and when I try to run rails server but I get this error:
Could not find gem 'mysql2 (>= 0) ruby' in the gems available on this machine.
Run bundle install to install missing gems.
So I run the bundle install and then I get the following error.
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
/usr/bin/ruby2.1 extconf.rb
mkmf.rb can't find header files for ruby at /usr/lib/ruby/include/ruby.h
extconf failed, exit code 1
Gem files will remain installed in /var/lib/gems/2.1.0/gems/mysql2-0.3.16 for inspection.
Results logged to /var/lib/gems/2.1.0/extensions/x86_64-linux/2.1.0/mysql2-0.3.16/gem_make.out
An error occurred while installing mysql2 (0.3.16), and Bundler cannot continue.
Make sure that `gem install mysql2 -v '0.3.16'` succeeds before bundling.
So I run gem install mysql2 -v '0.3.16' and it installs successfully however when I run bundle install again it gives me the same error:
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
/usr/bin/ruby2.1 extconf.rb
mkmf.rb can't find header files for ruby at /usr/lib/ruby/include/ruby.h
extconf failed, exit code 1
Gem files will remain installed in /var/lib/gems/2.1.0/gems/mysql2-0.3.16 for inspection.
Results logged to /var/lib/gems/2.1.0/extensions/x86_64-linux/2.1.0/mysql2-0.3.16/gem_make.out
An error occurred while installing mysql2 (0.3.16), and Bundler cannot continue.
Make sure that `gem install mysql2 -v '0.3.16'` succeeds before bundling.

Answer 1

Start again from scratch and this time you should install RVM as it is really good at handling all this stuff for you.
http://rvm.io/rvm/install
Make sure you get all the dependencies first, this code will check to see what you have and don't have:
for name in {bash,awk,sed,grep,ls,cp,tar,curl,gunzip,bunzip2,git,svn} ; do which $name ; done
Its also worth looking at the prerequisites page: http://rvm.io/rvm/prerequisites
You can run the below code to install rvm with Ruby 2.1.1 and Rails:
\curl -sSL https://get.rvm.io | bash -s stable --rails
Then To start using RVM:
/bin/bash --login
Its definitely worth using RVM it will make your life much easier when managing your ruby versions, gems etc, just make sure you read through the webpage so that you know how to use it.