On my fresh Ubuntu 11.04 box running Ruby 1.9.2 instead of the standard Ruby 1.8, I ran into some undocumented errors while installing the
mysql2 gem. Here’s what I was seeing:
$ gem install mysql2 Building native extensions. This could take a while... ERROR: Error installing mysql2: ERROR: Failed to build gem native extension. /usr/bin/ruby1.9.1 extconf.rb <internal:lib/rubygems/custom_require>:29:in `require': no such file to load -- mkmf (LoadError) from <internal:lib/rubygems/custom_require>:29:in `require' from extconf.rb:2:in `<main>' Gem files will remain installed in /usr/lib/ruby/gems/1.9.1/gems/mysql2-0.3.2 for inspection. Results logged to /usr/lib/ruby/gems/1.9.1/gems/mysql2-0.3.2/ext/mysql2/gem_make.out
This obviously isn’t all that helpful, nor did I find anything all that useful on Google – thankfully the issue is easy to solve. All that’s needed is to ensure that the following packages are installed:
sudo apt-get install libmysqlclient-dev libmysql-ruby1.9 ruby1.9.1-dev
Then you can try installing the gem, it should work, hopefully.