I have up2date setup for my servers to update most packages but ignore kernel updates as well as oracleasm-related updates. Kernel updates break things and must be done manually, when needed. However, I prefer using yum over up2date. But until now I did not find an easy way to tell yum to ignore updates on some packages. An old Duke mailing list had an improved man yum text that eluded to add multiple exclude=package* statements to the repos in /etc/yum.repos.d/. Thanks Duke!
Here is my example yum repo configuration with the excluded packages:
[el4_patch]name=Oracle Enterprise Linux - $releasever - $basearch - patchbaseurl=http://uln.example.com/yum/EL4/$releasever/patch/$basearch/exclude=kernel*exclude=oracleasm*gpgcheck=1enabled=1
Update2: When I moved the 'exclude' lines before the 'enabled' line, the yum update process does indeed ignore kernel updates, as expected. Before, I had the exclude lines after the line to enable that repo.
Update3: You can exclude at the main yum level (/etc/yum.conf) and on a per-repository basis. Using the command line switch disableexcludes=all you can then manually install the otherwise packages anyway. [Source]