Feasible Concept? Booting to local RAM Filesystem

[Richard]

I'd like some help to validate a general concept for PXE... am I heading down a feasible path here?

My goal is to have a system boot quickly via iPXE, run independently (local file system), and run entirely from RAM. The application is for burn-in testing of new systems. We need full access to the local disks to beat them up, swap them out, etc. A small-ish memory footprint would be nice-to-have because we also need to exercise RAM.

I've found processes for installing to local disk via PXE, and PXE-booting diskless workstations from an NFS share. This fellow seems to be the closest, apparently installing CentOS from an ISO to a RAM filesystem:
http://blog.braastad.org/?p=160
Now, I understand that PXE booting an ISO takes like 2x the RAM due to initrd, and doing a kickstart install vs. copy would seem like a much slower boot process. But, maybe his approach is the best option?

Is it conceptually feasible to combine some of these concepts? E.g., the NFS-based approach, adding in a copy-to-ramfs step and booting it locally? I'm wondering how the RAM filesystem would survive the boot, with a new kernel taking over.

FWIW, here's Redhat's approach for NFS-based booting:
https://access.redhat.com/site/documenta...stems.html

The appeal of their "diskless" approach is that I expect the boot time to be faster than a kickstart installation. And it'll be very easy for others to make changes to the source filesystem after I get it working (i.e., no ISO rebuilds). The drawback is this has an ongoing dependency on the NFS server, so I'd like to move the filesystem into local RAM. (The NFS server itself will be a test node at points, so won't always be online.)

Is it conceptually possible to PXE boot from NFS, copy the filesystem, and "remount" the root at the RAMdisk instead? Or PXE boot to an interim OS, create/populate the RAM filesystem, then boot the CentOS6 kernel from within it?

Thanks,
Richard