On Sat, Sep 25, 2010 at 12:11 AM, Steven Jenkins
<[email protected]> wrote:
> On Fri, Sep 24, 2010 at 1:28 PM, Phillip Moore
> <[email protected]> wrote:
>> I spent the morning working on this brain dump:
>> http://docs.openefs.org/efs-core-docs/DevGuide/Future/OpenAFS.html
>> Right now, there's a race on between the two sites that are trying to be the
>> first to bring up an EFS 3 domain, outside of my team (actually -- the first
>> other than me, personally, I think).
>> One of those sites wants to use EFS for OpenAFS environments, and there is
>> nothing I personally want more than to get work with OpenAFS again, so I'm
>> rooting for them :-P
>> Anyway, check out the doc if you have a few minutes.  It's FAR from
>> complete, and really just a brain dump, but it's touches on the bulk of the
>> issues we're going to have to figure out in order to make this work.
>> And make it work is precisely what I intend to do....
>
> I've put together some thoughts.  I'd be happy to provide a git diff
> of your doc if you prefer.  Otherwise, read on...
>
> Disclaimer: this was a brain-dump.  There is clearly more work/thinking that
> needs to occur.
>
> The 3 inter-related issues of EFS domains, Kerberos realms and uid/gid
> mappings across domains and realms is really about stitching those together.
> There are several projects in OpenAFS (or underway) that will probably
> help address this:
>
> - existing cross-(Kerberos)realm work in OpenAFS.  Currently,  there  is
> some limited cross-realm support (documentation is in the krb.conf and
> krb.excl man pages for OpenAFS).  By using that support, names from
> foreign realms can be treated as local.  Assuming all AFS ids are
> in sync across each cell, one can then configure each cell to trust the
> other cells (assuming that a cell maps to a Kerberos realm).
>
> That's a pretty unrealistic scenario.  It might be useful in some
> cases, but it won't be useful in the assumed more general case where
> the cells have not been centrally managed and thus AFS ids are not
> in sync across cells.
>
> - PTS extensions: c.f.,
>  https://datatracker.ietf.org/doc/draft-brashear-afs3-pts-extended-names/
> to provide a mechanism to map among AFS cells and Kerberos realms,
> as well as help with inconsistent uids in those cells & realms.
>
> Based on that, we should be able to view N realms as a logical whole
> (e.g., by first defining a 'canonical' mapping of uids, then building
> a mapping database.  Note that with the krb.excl file, we can exclude
> id's in certain realms, so a migration could conceivably happen in
> a controlled fashion).
>
> At a rough glance, these will get us very, very close.  Someone should
> touch base with Derrick and do some proof-of-concept mappings to verify
> this.  I don't know the status of that work -- Derrick mentioned today that
> he has some code, but it's not ready for anyone else to start playing with.
>
> - Various people who have played with using AD (or LDAP) as the
> backing store for PTS.  There are also other ways to solve this problem that
> have been discussed but aren't necessarily in the 'here's some code' stage.
> These projects may well play a part in a solution set to the cross-realm,
> cross-cell, inconsistent uid namespace problem.
>
> Misc notes:
>
> 1- We shouldn't require uid/gid consolidation to occur as a prequisite to
> adopting OpenEFS -- the organizational maturity bar for that is simply too
> high.
>
> 2- It's worth writing up a sample document describing how we want
> migration from your current multi-cell, multi-realm environment to EFS to
> occur.
>
> Creating mount points: more recent versions of OpenAFS (i.e., virtually
> anything that will be found in production) support dynamic mounting of
> volumes via a magic syntax (the exact syntax escapes me at the moment --
> I've not used it but only seen it mentioned a few times and was
> unable to locate the actual syntax)
>
> e.g.,
> /afs/example.org:user.wpmoore
>
> would be a path that would automagically mount the volume user.wpmoore.
>
> so the necessary fs mkmount could be done as follows:
>
> fs mkmount /afs/example.org:user.wpmoore/some/path some.volume
>
> without requiring any special pre and post mount hacking.
>

Found it after a bit more digging:

/afs/.:mount/example.org:user.wpmoore

i.e., I had neglected the /.:mount/

Steven
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