On Wed, Mar 28, 2007 at 03:41:27PM -0700, Adam Megacz wrote:
> 
> Also, now that we are running libnss-ptdb, there is no longer any need

Aha, you installed it..

> to create entries in /etc/passwd.  I've removed the "megacz" user from
> deleuze:/etc/passwd, and everything still works fine (note: we should

Yes, sure. We wanted to use LDAP to pull 
user/group info from it (and later all other user-related data).
So the plan has always been to not need /etc/passwd except for
local admin accounts, which we want to work even in case when
afs/kerberos or ldap is down. 
admin accounts = local files, user accounts = ldap + krb+afs.
(look at /etc/nsswitch.conf - it's modified appropriately.)

The modifications I've made to the script were also along
the same lines.. all users and IDs would be synced between ldap/krb/openafs.
Regardless of libnss-ptdb, this is a nice thing to have. And since
ldap and openafs names are exactly the same (user, user.cgi, ..),
the output from 'ls' is completely believeable.

does nss-ptdb cache results? I am sure that nscd does cache
database information (that's its primary function, and I have also
verified that connections to ldap are not being made after
the first call).

So as long as names/uids match between ldap and openafs (which
we want to), maybe the approach without libnss-ptdb is smoother.

> use some other mechanism such as pam to restrict logins on deleuze).

Yes, we already use it. In the scheme where we use ldap and
pam_ldap module, I've enabled check_host_attr in pam config
files, so login is allowed to machines which are listed in
user's host: attribute. (So in general, each user would have
host: mire and host: abulafia (when we put it on peer1) in their
ldap entry). (This is one thing that I forgot to add into the
LDIF within create-user script - will add).

> In fact, I recommend we adopt a policy of never adding an entry to
> /etc/passwd on any of hcoop's machines if a corresponding AFS identity
> exists -- this runs the risk of them falling out of sync.

Yes, ah I see your point now. But I think it's hurting us in the
long run. Why not make a small script that compares ldap and
openafs names/uids and reports any problems.. running once
a day..

Somehow I see ldap as the natural place to centralise all
information. The fact that openafs keeps a separate user/id
database is unfortunate for all sites who have broader
infrastructure in mind. So we should look at openafs as just
"this thing" with a database that has to be kept in sync with ldap;
not as something that we want to use standalone.

What do you think?


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