Seems the recent switch to python3 broke the mk-s390-cdboot tool ... 2017-10-19 09:09:19,177: Creating image file /mnt/koji/compose/rawhide/Fedora-Rawhide-20171019.n.0/work/s390x/buildinstall/Server/images/product.img from contents of /var/tmp/lorax.kmpex4wp/installroot/usr/share/lorax//product/ Creating image file /mnt/koji/compose/rawhide/Fedora-Rawhide-20171019.n.0/work/s390x/buildinstall/Server/images/product.img from contents of /var/tmp/lorax.kmpex4wp/installroot/usr/share/lorax//product/ 2017-10-19 09:09:46,016: command output: Creating bootable CD-ROM image... kernel is : /mnt/koji/compose/rawhide/Fedora-Rawhide-20171019.n.0/work/s390x/buildinstall/Server/images/kernel.img ramdisk is : /mnt/koji/compose/rawhide/Fedora-Rawhide-20171019.n.0/work/s390x/buildinstall/Server/images/initrd.img parmfile is: /mnt/koji/compose/rawhide/Fedora-Rawhide-20171019.n.0/work/s390x/buildinstall/Server/images/cdboot.prm outfile is : /mnt/koji/compose/rawhide/Fedora-Rawhide-20171019.n.0/work/s390x/buildinstall/Server/images/cdboot.img Traceback (most recent call last): File "/usr/bin/mk-s390-cdboot", line 112, in <module> main() File "/usr/bin/mk-s390-cdboot", line 109, in main configure_kernel(args.outfile, args.parmfile, size) File "/usr/bin/mk-s390-cdboot", line 80, in configure_kernel out_fd.write("\0" * KERNEL_CMDLINE_SIZE) TypeError: a bytes-like object is required, not 'str' ... for full log please see https://kojipkgs.fedoraproject.org//work/tasks/1853/22541853/mock_output.log Version-Release number of selected component (if applicable): lorax.s390x 28.0-1.fc28
Looks like this might be another fallout of the Python 3.6.3 bytes/strings change (bug 1501511).
Possibly related upstream commit: https://github.com/python/cpython/commit/a1115e1a0454f0548f96cace6ee97b286dfa1c0d
Hmm I see from the changelog though: "Convert mk-s390-cdboot to python3 (#1497141)" so I don't think it's related. to the pykickstart issue.
Correct, this was fallout from switching to python3 and not giving it a proper try.