(My best thought so far is having multiple hosts sharing a single /usr over NFS while having per-host root filesystems, but I've never actually seen that done. I've also thought about building a distro that kept its initramfs as root and just mounted everything else into it, but that's even further off the beaten path.)
HPC systems already have better systems for this sort of thing, e.g. Lmod which is modular.
I don’t think it’s a great idea to have /usr itself on NFS, given that things like /usr/bin/env is in most script shebangs and IMO should be stored locally. On some systems, many potential login shells are also stored in /usr/bin and not /bin.
Though part of me agrees that there are reliability concerns to keep in mind, the other part of me still thinks root on NFS is normal, at which point /usr seems rather minor in comparison:) I suspect some of this is cultural or a result of what you're used to.
- broken shell scripts that are hardcoded to "/bin/bash" rather than "/usr/bin/env bash" (this might work for a while, but what happens when they remove the symlink?)
- broken compiles because "/lib" and "/lib64" no longer exist, because of the lack of testing prior to making the change on behalf of users
- broken boots because initramfs (dracut/etc) isn't structured correctly after the change (see lack of testing).
I'm sure there's more but I'm not their personal testing infrastructure. I just want an OS that works without having to fight someone every 3 weeks because "everyone else is doing it, so we should too".
As to testing... yeah obviously this stuff should be thoroughly tested long before it hits users, but I was rather under the impression that it was tested extensively before getting to users. Again, if you've seen actual problems that made it past testing, feel free to point them out since that would greatly strengthen your criticism.
> I just want an OS that works without having to fight someone every 3 weeks because "everyone else is doing it, so we should too".
Are you super committed to Linux OSs? Because you might find the one of the BSDs or illumos more comfortable. Not that they never change (er, well, illumos might not), but at least it's not because of what anyone else does.
(And as an aside: Don't take this as an endorsement of merged usr; I actually prefer a separate /usr myself because I lean towards thinking that it's reasonable to have a read-only root and a rw /usr, or /usr on shared NFS, or any number of other "weird" systems... but I also culturally favor the BSDs, so take that as you will. I just think that if we're going to find fault, we should have the best evidence/arguments possible.)
