Did you know you can use systemd to turn on tmpfs for /tmp ???
I had no clue that was possible, always did it through fstab - but
systemctl is-enabled tmp.mount
That will tell you if systemd has configured /tmp to mount as tmpfs (default in CentOS 7 is no)
systemctl enable tmp.mount
That, as you can probably guess, tells systemd to mount /tmp as tmpfs next time the system boots.
-=-
Just thought I would pass it along in case others may benefit.
For me, I only need /tmp as tmpfs on my Bitcoin box - and then only when generating private keys for cold storage, SSDs are often not very good at securely deleting files. So I use tmpfs for /tmp and generate the private keys for cold storage to a file in /tmp and then print it from there (for storage in safe deposit box) - so that the private keys can't be recovered from the SSD.
Yes, booting off a CD to generate and then print works too, but that's bothersome.
Anyway just in case anyone else needs /tmp as tmpfs for anything, thought I'd pass the tip along.