Site Specific ACL Bits/chown: Was: [OpenAFS-devel] posix chown again

[Matt Benjamin]

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Hi List,

After out-of-band communication about the fate of Michael's build-time
configurable chown feature, I'd like to re-open the discussion, with a
view to addressing more directly the topic of site specific
customization of OpenAFS.

I find myself leaning to the view that this (ACL mods) is an area in
which, historically, there has been site-specific customization, and
collaterally, to the view that the cause of OpenAFS is helped more by
easing the workload on site administrators who might want this or
similar features, than it is harmed by the introduction of subtle
differences in ACL behavior within different cells.

The primary objection to the build-time configurable version
of this patch appears to have been Simon's opinion, shared by at least
Derrick:

> AFS should be a single, standard system, not some arcane combination
> that differs according to the particular configure options which were
> selected by each site. Users should be able to expect a consistent
> experience across multiple AFS sites, especially for items which they
> interact directly with such as ACLs.

and (earlier, but amplifying):

> Please, please, please don't make this configurable. From a user
> experience point of view it's horrific. Having the ACL bit which
> controls this behaviour differ between cells (and even between
> fileservers) will confuse any user who moves between sites, or even who
> reads a different site's documentation when trying to come to grips with
> AFS. It spectacularly violates the principle of least surprise.

Although I follow this reasoning, I'd at least tender the possibility
that the following reasoning is at least equally plausible, disregarding
for the moment the current scarcity of ACL bits:

1. it is in fact reasonable for different access control policies to be
applied in clearly distinct administrative domains (the definition of an
AFS cell);  Viewed in that way, it seems quite illogical to invoke "the
principle of least surprise" as an argument against site-specific ACL
behavior

2. insisting on ACL uniformity across sites is a neologism (some large
sites have historically wanted and created local policy in this area, so
the conservative position would appear to be, to continue to support it)

3. OpenAFS has an interest in making life easier for site administrators
where possible--removing the need for one site-local patch and test
cycle may seem like modest savings, but removing the need for several
could easily sum up to significantly reduced cost administrative cost

Again, I don't have very strong feelings about the feature per se, but I
would like to find ways to be more flexible with regard to site specific
customization in matters of administrative policy, and to sites'
perceived special needs, rather than less.

Sorry to belabor this,

Matt


- --

Matt Benjamin

The Linux Box
206 South Fifth Ave. Suite 150
Ann Arbor, MI  48104

http://linuxbox.com

tel. 734-761-4689
fax. 734-769-8938
cel. 734-216-5309

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