The MySQL gem required for resource/provider operations is not installed to the node via the current mysql::client recipe. A case around platform instructs centos nodes to install the 'ruby-mysql' package instead of running the gem_package 'mysql' resource.
The ruby-mysql package makes the assumption that your system ruby is installed by yum packages. It would be great if we could generalize this recipe instead to just be safe and install the mysql gem.
[Wed, 01 Feb 2012 21:13:41 +0100] INFO: Processing mysql_database[merlin_production] action create (merlin::database_server line 25)
[Wed, 01 Feb 2012 21:13:41 +0100] ERROR: Running exception handlers
[Wed, 01 Feb 2012 21:13:41 +0100] ERROR: Exception handlers complete
[Wed, 01 Feb 2012 21:13:41 +0100] FATAL: Stacktrace dumped to /tmp/vagrant-chef-1/chef-stacktrace.out
[Wed, 01 Feb 2012 21:13:41 +0100] FATAL: LoadError: no such file to load – mysql