Can I put an OS installation onto a software RAID?
Unfortunately, no. One cannot boot off a software RAID0, RAID5, or span. A hardware controller is needed to do this.
You cannot start an OS off the software RAID for the array is not properly readable before the operating system is fully started up, and the operating system itself is on the array.
The only option is to start an OS using a software RAID 1, and even that is not that simple. To boot from a "second" disk of a software RAID1, you probably need to manually copy the master boot record first, because usually the master boot record is not copied automatically.