On Thu, Aug 13, 2009 at 4:23 AM, Brian Ruthven - Sun
UK<[email protected]> wrote:
>
> Once it's in that state, can you run the following please:
>
> # truss -Tgetpid -p <PID>
> # pstack <PID>
> # pfiles <PID>
> # prun <PID>
>
> The truss command will stop the process on a getpid call (confirm the S
> column has a 'T' in it with "/usr/bin/ps -opid,s,comm -p <PID>"), and then
> the pstack and pfiles will snapshot a point we're interested in. The prun
> will put the process back in the state it was in so you can kill / svcadm
> restart it.
>
>
> I found bug 5060500 which describes a possible cause of this. However, the
> fix for 6537549 added the signal(SIGPIPE SIG_IGN) to nscd, so this explains
> why the process doesn't die any more.
>
> Both bugs can be seen here:
> http://bugs.opensolaris.org/bugdatabase/view_bug.do?bug_id=5060500
> http://bugs.opensolaris.org/bugdatabase/view_bug.do?bug_id=6537549

Perhaps related to this, I've had times where a misbehaving load
balancer in front of LDAP servers causes the lookup through nscd to
fail entirely rather than trying any additonal configured LDAP
servers.  By fail entirely, I mean that getpw*() fails, causing ssh(1)
to say "You do not exist, go away!"  After several tries, it seems to
grab the next LDAP server.  I would expect that if one LDAP server
isn't able to respond to queries properly that nscd would try the next
one before returning a result or error to the caller.

When I used ldapsearch I found that the load balancer was sending a
TCP RST while ldapsearch was waiting for a response to the bind
request.  Packet traces show that in the successul ldapsearch session,
the TCP session is concluded in an orderly manner by the client
sending a packet with FIN set. In contrast, the unsuccessful
ldapsearch session shows the load balancer sends a packet with RST
set.

If anyone is interested in more detail, let me know.  I think that I
might be able to reproduce this today.

-- 
Mike Gerdts
http://mgerdts.blogspot.com/
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