You need Pearl and SSH for Repository Role.
HW needs to be compatible with Intel (no Power/Sparc/ARM)
You can choose whatever linux distribution you like.
I suggest to use SLES or RHEL because of Support of Linux itself.
Most customer choose their standard Linux distribution, because of patch management/monitoring and admin training.
If you install it on a Hardware Box, check also HCL of Linux Distribution. (Disk and Network I/O is key, so you need stable and good drivers for your Hardware).