On Debian/Ubuntu installs of RPM, /usr/lib/rpm/macros sets
%_dbpath %(echo $HOME/.rpmdb)
which makes quite a bit of sense, because RPM is not the system
packager and thus RPM is setup to install things into a hierarchy in
the users homedir.
However, this messes things up when building a Fedora chroot on an
Ubuntu platform.
We use RPM & yum from the base-system to bootstrap the Fedora chroot.
While both obey --root flags, they still pick up the %_dbpath macro
and so end up creating the RPM database in <chroot>/home/user/.rpmdb
After we have bootstrapped yum/dnf, we execute further installation
commands from inside the chroot -- where we now have the Fedora
version of /usr/lib/rpm/macros and hence have _dbpath set to
/var/lib/rpm -- except there is no rpm database there.
Should anyone be finding this in the future, the actual issue that
appears is
$ sudo chroot /opt/dib_tmp/image.b6B5S3f6/mnt dnf makecache
Error: Failed to synchronize cache for repo 'fedora' from \
'https://mirrors.fedoraproject.org/metalink?repo=fedora-$releasever&arch=x86_64': \
Cannot prepare internal mirrorlist: file "repomd.xml" was not found in metalink
Note the issue there is that $releasever is not expanded, because the
rpmdb where this info is kept is not populated.
The trick is to make sure we override this value when using the host
rpm/yum to setup the chroot. The bare rpm calls, which we use to
install the repos, have a --dbpath argument where we can override
this. yum does not however, so we override this in the global
~/.rpmmacros while we are installing the packaging tools and
dependencies into the chroot.
Copious comments are included, because this is super-confusing.
Change-Id: I20801150ea02d1c64f118eb969fb2aec473476f7
3f3850aa0f