The VMware vCloud Director 1.5 runs on the Red Hat Enterprise Linux 5.6 platform. It is supported by VMware only on version 5.6 of the Red Hat Enterprise Linux. If you are not careful and try to patch the operating system on the vCloud Director 1.5 system, you could find yourself with a RHEL 5.7 or RHEL 5.8 Release, which would cause vCloud Director to break.
To ensure that your vCloud Director 1.5 stays on the Red Hat Enterprise Linux 5.6 Release and only download patches for the operating system, we need to add a single line to the /etc/yum.conf file.
I simply add the following line in /etc/yum.conf
This will exclude all newer Red Hat Releases from getting installed by yum & the Red Hat Network.
I hope this will save you so unneeded trouble.