sudo mkdir /var/tmp/zzol9

sudo rpm --root=/var/tmp/zzol9/ --import -D '_db_backend sqlite' /etc/pki/rpm-gpg/RPM-GPG-KEY-oracle 
#tree zzol9/

// do the business install a minimal install, enough to run the dnf installer
sudo dnf --releasever=9 --installroot=/var/tmp/zzol9 install oraclelinux-release-el9 dnf rpm nano dnf-plugins-core glibc-langpack-en --nogpgcheck \
 --nodocs --setopt=module_platform_id=platform:el9 --repofrompath=mga8rel,https://yum.oracle.com/repo/OracleLinux/OL9/baseos/latest/x86_64/  \
  --disablerepo=* --enablerepo=mga8rel --exclude=gnome*

cd
mkdir tmpstrap && cd $_

cat >> schroot.sh<<EOL
#!/bin/sh

PATH=$PATH:/sbin:/usr/sbin

# /var/cache/pbuilder
RT=/var/tmp/${1-"zzol9"}

echo "rt=$RT"

# below for partitioned block device
#mount $VM $RT -o offset=1048576
## --------- end control -------

# bindmount
#BM=home/mockbuild/pbdeps

for i in dev dev/pts proc sys run ; do
        mount -o bind /$i $RT/$i
        echo "mount $i"
done

LC_ALL=C chroot $RT /bin/bash

for i in run dev/pts dev proc sys ; do
        umount $RT/$i
        echo "umount $i"
done

EOL

chmod +x schroot.sh 

// enter chroot, add a nameserver to /etc/resolv.conf, clean all
sudo ./schroot.sh 

cd /var/tmp/zzol9/
sudo tar -Ipzstd -cf ~/ol9-min.tar.zst ./