Jon Detert wrote:
> I'm pretty new to the task of upgrading CentOS or RedHat o.s.'s. I'm more
> familiar with upgrading Debian based o.s.'s. Here are my questions:
>
> 1) will yum ever upgrade the major version? I understand that there is no
> upgrade path from v5.x to v6.x, but is that always the case? e.g. was
> there an upgrade path from v4.x -> v5.x? If yum is capable of doing so,
> what are the command-line arguments necessary?
Never has been a full release upgrade path - that's a bad idea, too much
cruft.
>
> 2) can I upgrade a minor version to any other greater minor number, or
> only to the greatest? E.g. if i have a v5.4 box, can i upgrade to v5.5 or
> v5.6, or only to v5.7 (currently the latest)?
Yum update *will* do that without a problem.
>
> 3) if an upgrade delivers a new kernel, am I obligated to run it (i.e.
> will the old kernel remain installed, or will the upgrade remove the old
> kernel)? If not, does the upgrade automatically update grub such that the
> new kernel becomes the default? Will the upgraded box function properly
> without running the new kernel?
No, you're not. It will update /etc/grub.conf (a link to
/boot/grub/grub.conf), and the next time you reboot, it will default to
the new kernel. It does remove the oldest kernel, but leave (I believe) at
least three (current, and the last two).
>
> 4) aside from when an upgrade includes a new kernel, how can I tell when a
> reboot is necessary? I gather that a new glibc may require services to be
> restarted, but is a reboot strictly necessary?
New kernel.
>
> 5) is there a way to apply only the updates that were made for the given
> minor version you're currently at? E.g. if I'm at v5.5, how can I only
> apply updates that were made prior to v5.6's availability?
Tune /etc/yum.repos.d to point to explicity subreleases is, I think, the
answer.
mark