On Fri, Jan 15, 2016 at 2:24 AM, Tomáš Smetana <tsmetana@redhat.com> wrote:

I tend to use systemd-nspawn containers for building rpms. So for example, I
have a Fedora 24 system and use its dnf to create e.g. Centos 7 container
root and then build Centos rpms from within that container. If I understand
the change correctly, this is going to break since the Centos 7 rpm-build
will not be able to read the database created by the Fedora 24 dnf.

I personally prefer to build my containers by starting with the raw files that are used to build the base CentOS and Fedora Docker containers:

https://raw.githubusercontent.com/CentOS/sig-cloud-instance-images/CentOS-7.2.1511/docker/centos-7.2.1511-docker.tar.xz
https://download.fedoraproject.org/pub/fedora/linux/releases/23/Docker/x86_64/Fedora-Docker-Base-23-20151030.x86_64.tar.xz

The CentOS tarfile can be easily untarred into an empty directory. The Fedora tarball contains a layer.tar file that contains the raw filesystem.

I like doing it this way because I don't have to depend on the host yum/dnf to set up the filesystem. This would work too for non-rpm systems (or for RHEL) as well but I haven't had the need so I haven't searched for the appropriate media.

Jeff Ollie