This patch adds drop-in for named.service that refers to non-existing paths that results in failure to start service.

Dec 28 09:41:45 leap15 systemd[1]: Starting Berkeley Internet Name Domain (DNS)...
Dec 28 09:41:45 leap15 systemd[19283]: named.service: Failed to set up mount namespacing: /run/systemd/unit-root/run/named: No such file or directory
Dec 28 09:41:45 leap15 systemd[19283]: named.service: Failed at step NAMESPACE spawning /usr/sbin/named.init: No such file or directory
Dec 28 09:41:45 leap15 systemd[1]: named.service: Control process exited, code=exited, status=226/NAMESPACE
Dec 28 09:41:45 leap15 systemd[1]: named.service: Failed with result 'exit-code'.
Dec 28 09:41:45 leap15 systemd[1]: Failed to start Berkeley Internet Name Domain (DNS).

If drop-in is disabled by using

sudo mkdir /etc/systemd/system/named.service.d
sudo touch /etc/systemd/system/named.service.d/26-samba-dlz.conf

named.service starts normally.