[Yum] Problematic 'yum' repository paths using --installroot option

[Michal Domonkos]

On Mon, Feb 3, 2020 at 5:08 PM Peter Willis <pwillis at aslenv.com> wrote:
> Thank you Michal.  This clarifies and resolves the issue for me.

Glad to hear that! :)

> Just as a follow up, the man page for the yum utility does not mention the need for pre-existing variables paths within the target root path. Nor does the man page indicate the required structure, convention, or required values of the directories and variables. This is the information that was lacking.

I have to agree; it's not particularly clear as to where the
individual config files are taken from when an --installroot is
specified, and which exactly they are anyway.  IIRC, though, all of
the config files are first looked up inside the installroot, and only
taken from the host if missing.

That being said, it's true that one could perhaps benefit from a "yum
bootstrap" command that would plant all the necessary YUM config files
inside the installroot first, so that it's not necessary to do that
manually should the user require a different configuration in the
installroot.

> What are the standard directories, files, variable names and values that yum expects and why?
> Those information should probably be added to the documentation.

Actually, there's a mention of the /etc/yum/vars/ directory in the
yum.conf(5) man page, at the very bottom, although it doesn't say
anything about the installroot:

[...]
VARIABLES
[...]
As of 3.2.28, any properly named file in /etc/yum/vars is turned into
a variable named after the filename (or overrides any of the above
variables).  Filenames  may  contain  only alphanumeric characters and
underscores and be in lowercase.
[...]

The thing is, YUM is already in maintenance mode and we (as Red Hat)
only backport selected high-impact bug fixes to RHEL-7.  Man page
changes, unless really critical, wouldn't count, I'm afraid.  FWIW,
dnf(8), which is shipped with RHEL-8, does a much better job at
documenting the --installroot feature in its man page, I believe.

Best regards,

Michal