I recently set up helix-gitswarm on an AWS instance with RHEL7 and had the installer script fail on me. It claimed the distro was unknown.
The cause turned out to be a missing
lsb_release binary on the Red Hat machine: installing the
redhat-lsb-core package in yum added it and allowed the script to continue.
I also made sure to mount magnetic storage on
/var/opt before installing, so that the repository storage had plenty of room.
At the time of writing, RHEL7 is difficult to install helix-gitswarm on (at least compared to Ubuntu); I later found some documentation buried in the perforce site that suggested against using that platform.