Re: NetBSD netboot with maximal cross-architecture sharing

[Chris Hanson <cmhanson%eschatologist.net@localhost>]

On May 10, 2020, at 4:55 PM, Jason Thorpe <thorpej%me.com@localhost> wrote:
> 
> On May 10, 2020, at 1:58 PM, Chris Hanson <cmhanson%eschatologist.net@localhost> wrote:
>> 
>> Are there any documented best practices for setting NetBSD up in this way? If I want to set up (say) NetBSD-current to netboot on several older systems with different architectures, I could naïvely just create a distinct root for each system, but I’d really like to share what I can (beyond home directories) since so much of the OS content will be the same.
> 
> /usr/share is named as such precisely because it's sharable across all platforms.

Sure, but is there *more* that can be shared across platforms?

Taking an example from my own network, I have both sun3 and hp300 hardware on which I can network-boot NetBSD. Is there a good way to set up sharing most of the m68k-architecture binaries while not sharing the sun3-platform and hp300-platform binaries?

I expect that with a bit of work I’ll be able to set up the following for netboot for a particular version of NetBSD:

- /home to be fully shared among all my systems running NetBSD
- /usr/share to be fully shared among all my systems running a particular version of NetBSD
- / to be entirely distinct per-system, mainly as a host for symbolic links, /etc content, /var content, and /tmp
- most of /bin, /sbin, /lib, /usr to be shared per-architecture (m68k, ppc, mips, etc.)
- kernel and modules to be shared per-platform (sun3, hp300, pmax, etc.) and not per-architecture

Am I on the right track here? Or does the fact that each platform is basically a world build make it risky to share per-architecture binaries too? And will the structure of the archives produced by a NetBSD build right now make doing the above difficult, enough so that I’d be better off just burning disk space on an install per system, with just shared /home and /usr/share?

  -- Chris