If you interrupt dlrn during mock build you might get an error
OSError: [Errno 16] Device or resource busy: '/var/lib/mock/dlrn-centos-x86_64/root/var/cache/yum'
Solution is to clear left-over bind mount as root:
# umount /var/lib/mock/dlrn-centos-x86_64/root/var/cache/yum
If the git clone operation fails for a package, DLRN will try to remove the
source directory using sudo. Please make sure the user running DLRN can run
rm -rf /path/to/dlrn/data/* without being asked for a password, otherwise
DLRN will fail to process new commits.