After most tests, when identity_upcall is set to NONE, it looks like only ACL
using secondary groups are not satisfied.
If secondary groups are properly defined on clients, accesses are granted as
expected.
Aurélien
Le 09/01/2019 14:31, « lustre-discuss au nom de Degremont, Aurelien »
<lustre-discuss-boun...@lists.lustre.org au nom de degre...@amazon.com> a écrit
:
Hi Daniel!
The secondary group thing was ok to me. I got this idea even if there is
some weird results during my tests. Looks like you can overwrite MDT checks if
user and group is properly defined on client node. Cache effects?
ACL is really the thing I was interested in. Who is validating the ACLs?
MDT, client or both? Do you think ACL could be properly applied if user/groups
are only defined on client side and identity_upcall is disabled on MDT side?
Thanks
Aurélien
Le 09/01/2019 12:22, « lustre-discuss au nom de Daniel Kobras »
<lustre-discuss-boun...@lists.lustre.org au nom de kob...@puzzle-itc.de> a
écrit :
Hi Aurélien!
Am 09.01.19 um 11:48 schrieb Degremont, Aurelien:
> When disabling identity_upcall on a MDT, you get this message in
system
> logs:
>
> lustre-MDT0000: disable "identity_upcall" with ACL enabled maybe
cause
> unexpected "EACCESS"
>
> I’m trying to understand what could be a scenario that shows this
problem?
> What is the implication, or rather, how identity_upcall works?
Without an identity_upcall, all Lustre users effectively lose their
secondary group memberships. These are not passed in the RPCs, but
evaluated on the MDS instead. The default l_getidentity receives a
numeric uid, queries NSS to obtain the corresponding account's list of
gids, and passes the list back to the kernel. As a test scenario, just
try to access a file or directory from an account that only has access
permissions via one of its secondardy groups. (The log message is a bit
misleading--you don't actually need to use ACLs, ordinary group
permissions are sufficient.)
Kind regards,
Daniel
--
Daniel Kobras
Principal Architect
Puzzle ITC Deutschland
+49 7071 14316 0
www.puzzle-itc.de
--
Puzzle ITC Deutschland GmbH
Sitz der Gesellschaft: Jurastr. 27/1, 72072
Tübingen
Eingetragen am Amtsgericht Stuttgart HRB 765802
Geschäftsführer:
Lukas Kallies, Daniel Kobras, Mark Pröhl
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