On an up to date Fedora 26, attempting a mock build targeting EPEL 5, specifically "-r epel-5-x86_64" (on Fedora x86_64) fails thusly: DEBUG util.py:606: child environment: None DEBUG util.py:533: Executing command: ['/usr/bin/systemd-nspawn', '-q', '- M', '61336fe75098477eaace9727c7cec7c1', '-D', '/var/lib/mock/epel-5- x86_64/root', '-a', '--setenv=TERM=vt100', '--setenv=SHELL=/bin/bash', '-- setenv=HOME=/builddir', '--setenv=HOSTNAME=mock', '-- setenv=PATH=/usr/bin:/bin:/usr/sbin:/sbin', '--setenv=PROMPT_COMMAND=printf "\\033]0;<mock-chroot>\\007"', '--setenv=PS1=<mock-chroot> \\s-\\v\\$ ', '-- setenv=LANG=en_US.utf8', '-u', 'mockbuild', '/bin/rpm', '-Uvh', '--nodeps', '/builddir/build/originals/courier-unicode-2.0-5.fc26.src.rpm'] with env {'TERM': 'vt100', 'SHELL': '/bin/bash', 'HOME': '/builddir', 'HOSTNAME': 'mock', 'PATH': '/usr/bin:/bin:/usr/sbin:/sbin', 'PROMPT_COMMAND': 'printf "\\033]0;<mock-chroot>\\007"', 'PS1': '<mock-chroot> \\s-\\v\\$ ', 'LANG': 'en_US.utf8'} and shell False DEBUG util.py:307: Unsharing. Flags: 134217728 DEBUG util.py:450: host's /etc/localtime is not a symlink, not updating container timezone. DEBUG util.py:450: getent initgroups failed with error code 1. DEBUG util.py:450: Failed to parse group data from getent. DEBUG util.py:450: Child died too early. DEBUG util.py:588: Child return code was: 1 It appears that mock wants to run systemd-nspawn inside the EPEL-5 chroot, which is not going to get very far. Should this work/be supported, on F26? I'm just trying to see if some of my stuff still builds on 5.