I'm not sure if this is a OEL question or OEM question, or maybe both. What is preferred or recommended way of doing updates, yum or up2date ?
We have a local yum server and our hosts mostly do yum, but some do up2date. Grid Control seems to want to use up2date, but up2date is less flexible. I read that Redhat will not be shipping up2date with future releases of of Rhel, so that makes me wonder too.
There is no preferred way. OEM gives you a choice, either YUM or up2date
In RHEL5, Red Hat moved away from up2date to YUM. Oracle Enterprise Linux 5 (OEL5) and the Unbreakable Linux Network (ULN, http://linux.oracle.com/) use up2date. That said, you can set up a local yum repos based on ULN and, optionally, have OEM patch your hosts from it.
Aside from managing updates with OEM (I have no experience with that), I see a clear distinction:
up2date provides updates and packages. it requires a ULN account. the most important thing is the updates provides bug and security enhancements for the version you are running. it can be used to install additional packages from the up2date server.
yum provides the additional packages which come on the DVD for free, but does not provide updates and fixes. just the packages as they are delivered on DVD. (see: http://public-yum.oracle.com/)
as sergio also says: you can install a yum server for yourself too.
Red Hat Network (RHN) allows customers to define classes of machines and then provision all machines in that class identically. RHN can also be configured to push changes to client machines, if desired.
Oracle Unbreakable Linux Network (ULN) keeps track the RPM inventory for each separate client machine. ULN is a pull-only model where clients download packages on demand. ULN does provide an errata notification service via email.
As far an ULN clients are concerned, using up2date(8) or yum(8) is a shrug. Oracle's public YUM repository contains only the RPM packages from the given release but no packages updated since then. If you have a ULN support agreement then using up2date(8) to get the packages onto a local machine is indicated.
While RHN provides a satellite server where a company can set up it's own equivalent to RHN (and keep all the details of their internal machines secret, besides saving all that bandwidth), Oracle provides the tools allowing a customer machine to be set up as a local mirror of the ULN package repository (including updated RPM's) to which internal machines connect for updates. In fact, this is strongly encouraged since it is a win-win scenario.
In summary, between Oracle and ULN customers up2date(8) is best, else yum(8). Internally, customers should set up their own yum(8) repository. The Oracle/customer connection may change in the future but probably not soon.