gssapi requires Ruby version >= 1.9.1. on gem install

I'm trying to install knife-cloudstack plugin using gem install on Ubuntu 12.04 with chef-client configured and got error as said in title.

>gem install knife-cloudstack
ERROR: Error installing knife-cloudstack:
       gssapi requires Ruby version >= 1.9.1

So i tried installing apt-get install ruby1.9.3, but still the same error.

Also, the version of ruby is shown 1.9.3

ruby --version ruby 1.9.3p0 (2011-10-30 revision 33570) [i686-linux]

To get more confused, when i run sudo update-alternatives --config ruby , its showing output as:

There are 2 choices for the alternative ruby (providing /usr/bin/ruby).

     Selection    Path                Priority   Status
   ------------------------------------------------------------
     0            /usr/bin/ruby1.8     50        auto mode
     1            /usr/bin/ruby1.8     50        manual mode
   * 2            /usr/bin/ruby1.9.1   10        manual mode

   Press enter to keep the current choice[*], or type selection number:

PS: Initially the * was on Selection:0, i changed it later to 2.

Now where is ruby1.9.3? Even if i installed ruby1.9.3, why its taking other version?Anyone knowing what's causing the issue?

Thanks.

Solution

The package is called 1.9.1 because that is the ABI version.

Ruby uses two parallel versioning schemes: the `Ruby library compatibility version' (1.9.1 for this package), which is similar to a library SONAME, and the 'Ruby version' (1.9.3 for this package). Ruby packages in Debian are named using the Ruby library compatibility version, which is sometimes confusing for users who do not follow Ruby development closely. This package depends on the ruby1.9.1 package, and provides compatibility symbolic links from 1.9.3 executables and manual pages to their 1.9.1 counterparts.