You should already have the repositories installed for euca2ools, EPEL, and ELRepo from your 3.1.x installation. If you do not have these installed, refer to the installation instructions to find out how to add these to your machines.
The steps in this section should be performed on all machines with Eucalyptus installed.
yum install http://downloads.eucalyptus.com/software/eucalyptus/3.2/centos/6/x86_64/eucalyptus-release-3.2.noarch.rpm
yum install eucalyptus-enterprise-release-3.2*.noarch.rpm