Does someone have a working tmp on tmpfs via systemctl enable tmp.mount under CentOS8/RHEL8? This seems to work straight in EL7 ... # LANG=C systemctl enable tmp.mount The unit files have no installation config (WantedBy, RequiredBy, Also, Alias settings in the [Install] section, and DefaultInstance for template units). This means they are not meant to be enabled using systemctl. Possible reasons for having this kind of units are: 1) A unit may be statically enabled by being symlinked from another unit's .wants/ or .requires/ directory. 2) A unit's purpose may be to act as a helper for some other unit which has a requirement dependency on it. 3) A unit may be started when needed via activation (socket, path, timer, D-Bus, udev, scripted systemctl call, ...). 4) In case of template units, the unit is meant to be enabled with some instance name specified. -- Leon