Comment # 8 on bug 940522 from Franck Bui

I think this one is a duplicate of bnc#949574: tmp.mount should be started
during boot in any cases since it's required by basic.target unit unless
tmp.mount is masked.

What's not clear to me is why PrivateTmp=yes adds a "require" dependency
explicitely on tmp.mount... it should be assumed to be started at boot through
the 'basic.target'.

@Jiri: until the fix done in bnc#949574 reaches TW, I suggest 2 workarounds:

  - if you want systemd to setup a tmpfs on /tmp automatically on boot you can
force it with "systemctl add-requires basic.target tmp.mount". That's normally
the default behaviour if /tmp is not defined in /etc/fstab.

  - if you don't want to mount anything on /tmp, you can "systemctl mask
tmp.mount". The previous workaround still applies actually since it doesn't
hurt and can be useful if you change your mind and want to use tmpfs.