Red Hat Linux 8.0 hangs as an LDAP client when LDAP server goes down

["Manuel Amador (Rudd-O)" <amadorm@usm.edu.ec>]

Hey, everyone!

I'm having this tough problem around.  We've set up successfully a 
network with Directory administrator, OpenLDAP, and a few servers posing 
as LDAP clients, for centralized authentication management.  This all 
goes well, if we don't notice that OpenLDAP is much slower than the 
local password database.

Now, when the LDAP server goes down, all the Red Hat 8.0 servers using 
it as authentication source hang.  Completely hang.  No log-ins 
possible, open root sessions malfunction (ps, ls, all commands hang).  I 
do know this is supposed to happen with the current state of the art in 
open source LDAP tools.  I suppose I can live with this, temporarily, 
but it really shouldn't happen (software should be smart, fail smartly 
and let the rest of the system go on).

What strikes me as very odd is that when the LDAP server comes back up, 
the clients do NOT return to a working state.  They all have to be 
power-cycled (a vulcan nerve pinch doesn't affect them).  This is what 
it's not acceptable.  We could deal with five minutes downtime in all 
our servers when the LDAP server has to go down for maintenance, but we 
simply can't deal with powercycling all Linux servers when the LDAP 
server goes down, or powering them down in a certain order.

Two questions:

1) Do any of you guys know of people enhancing NSS, PAM and others to 
make LDAP authentication run smoothly when the LDAP server fails 
(perhaps immediately returning instead of hanging forever and ever).  I 
know I could set up a backup server, and at some point we will do.  But 
the server should just chug along when the LDAP server fails (perhaps 
losing functionality for LDAP-stored users, but no more).

2) Why do all LDAP clients hang when the server goes down, and remain 
hung even after it has come up?

Thanks in advance.

    Manuel Amador
    Universidad Tecnica Federico Santa Maria
     Campus Guayaquil
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