JC: There has been a lot of work around connection management around
this version, the "accept" thread that is responsible for polling the
ldap/ldaps ports for connection attempts was introduced in a previous
version. This thread will fail to accept a new connection when the
number of existing connections hits a certain limit. However, when
this happens you should see this message in the error logs: "Not
listening for new connections - too many fds open", so IMHO I think
the error message you see is related to something else.
I have the 6 minute log when the event occurs, but I am not seeing "Not
listening" or "fds" in the logs.
JC: I failed to reproduce this issue locally with the same version and
file descriptor limit (8192) and 10k connections. So I am not aware of
anything else that might cause this error message.
How are you testing this ? Can you give me your load testing script??? I
have used the "ldclt" script, and I see it does things, but based on the
output I think its doing add/delete/modify/searches, but I cant tell how
many connects and disconnects. If I had a script, to emulate this, I can
see if I can get the developer or maybe I tweak their bonsai code.
Thanks so much,
Gary
On 10/9/24 09:24, James Chapman wrote:
On Wed, Oct 9, 2024 at 11:36 AM Joe Fletcher <jflet...@sscinc.com> wrote:
Just a thought: what are the open files limits set to on the system?
I’ve seen plenty of cases where increasing descriptor limits can
help in these instances.
*From:*Thierry Bordaz via 389-users
<389-users@lists.fedoraproject.org>
*Sent:* Wednesday, October 9, 2024 10:30 AM
*To:* Gary Waters <gwat...@caltech.edu>; General discussion list
for the 389 Directory server project.
<389-users@lists.fedoraproject.org>; Marc Sauton
<msau...@redhat.com>; James Chapman <jacha...@redhat.com>
*Cc:* gwaters-...@caltech.edu; Thierry Bordaz <tbor...@redhat.com>
*Subject:* [389-users] Re: Inconsistent Ldap connection issues
**** The e-mail below is from an external source. Please do not
open attachments or click links from an unknown or suspicious
origin. ****
Hi Gary,
My understanding is that a single client opens ~10K connections in
~6min, that is an average of 26 connections per second. It creates
a set of established connections that spike up to 961 parallel
connections. The problem being that from time to time the client
reports 'can not contact LDAP server' and while you are running
2.4 this problem did not occur in 1.4.3. Am I correct ?
My first guess is that Marc is correct and tuning of tcp param
should be the culprit. Now it does not explain why it occurs only
in 2.4 but may be you were running 1.4.3 on RHEL7 and are running
2.4 on RHEL8.
2.4 contains significant changes around that area. I do not recall
all commit in connection handling side. AFAIK what is "new" is a
dedicated listener thread (polling on ports 389/636/ldapi for new
connections) and a multiple polling threads (polling the
established connections)
My understanding is that your problem impacts the listener thread
as it is responsible to accept new connections and it is the new
problem you detect in 2.4. @james did I miss something ?
JC: There has been a lot of work around connection management around
this version, the "accept" thread that is responsible for polling the
ldap/ldaps ports for connection attempts was introduced in a previous
version. This thread will fail to accept a new connection when the
number of existing connections hits a certain limit. However, when
this happens you should see this message in the error logs: "Not
listening for new connections - too many fds open", so IMHO I think
the error message you see is related to something else.
If the culprit is not in TCP tuning, @james do you remember known
bugs that would limit the listener thread ?
JC: I failed to reproduce this issue locally with the same version and
file descriptor limit (8192) and 10k connections. So I am not aware of
anything else that might cause this error message.
best regards
thierry
On 10/8/24 7:36 PM, Gary Waters wrote:
Hi Thierry,
Ah yes of course. Here is 1 run of their web app load test, it
is 6 minutes long, and it should mostly be only the test it
self. I will start looking for
We encountered 2 "Can not contact ldap server" errors during
this run.
2 cant contact ldap server errors in this run
----------- Access Log Output ------------
Start of Logs: 08/Oct/2024:09:53:35.810833927
End of Logs: 08/Oct/2024:09:59:52.361830449
Processed Log Time: 0 Hours, 6 Minutes, 16.550998016 Seconds
Restarts: 1
Secure Protocol Versions:
- TLS1.2 128-bit AES-GCM (9833 connections)
Peak Concurrent Connections: 689
Total Operations: 86412
Total Results: 86412
Overall Performance: 100.0%
Total Connections: 9933 (26.38/sec) (1582.73/min)
- LDAP Connections: 9933 (26.38/sec) (1582.73/min)
- LDAPI Connections: 0 (0.00/sec) (0.00/min)
- LDAPS Connections: 0 (0.00/sec) (0.00/min)
- StartTLS Extended Ops: 9833 (26.11/sec) (1566.80/min)
Searches: 66647 (176.99/sec) (10619.60/min)
Modifications: 0 (0.00/sec) (0.00/min)
Adds: 0 (0.00/sec) (0.00/min)
Deletes: 0 (0.00/sec) (0.00/min)
Mod RDNs: 0 (0.00/sec) (0.00/min)
Compares: 0 (0.00/sec) (0.00/min)
Binds: 9932 (26.38/sec) (1582.57/min)
Average wtime (wait time): 0.001407368
Average optime (op time): 0.003186859
Average etime (elapsed time): 0.004591048
Multi-factor Authentications: 0
Proxied Auth Operations: 0
Persistent Searches: 0
Internal Operations: 0
Entry Operations: 0
Extended Operations: 9833
Abandoned Requests: 0
Smart Referrals Received: 0
VLV Operations: 0
VLV Unindexed Searches: 0
VLV Unindexed Components: 0
SORT Operations: 0
Entire Search Base Queries: 0
Paged Searches: 0
Unindexed Searches: 0
Unindexed Components: 0
Invalid Attribute Filters: 0
FDs Taken: 9933
FDs Returned: 9932
Highest FD Taken: 961
Broken Pipes: 0
Connections Reset By Peer: 0
Resource Unavailable: 0
Max BER Size Exceeded: 0
Binds: 9932
Unbinds: 9225
-----------------------------------
- LDAP v2 Binds: 0
- LDAP v3 Binds: 9932
- AUTOBINDs(LDAPI): 0
- SSL Client Binds: 0
- Failed SSL Client Binds: 0
- SASL Binds: 0
- Directory Manager Binds: 0
- Anonymous Binds: 99
================
After this run I bumped up these from 4096,
net.ipv4.tcp_max_syn_backlog = 6144
net.core.somaxconn = 6144
Yet we still get the ldap errors (this one and the start tls
request error previously mentioned.)
Should I bump up the
On 10/8/24 03:47, Thierry Bordaz wrote:
Hi Gary,
I meant that the access logs covered 5hours. It would be
helpful to capture/focus on the logs from the few minutes
before/after the time when the problem occurred. Then
check from those limited logs if there is a pattern or
unexpected events (long operation, no operation, abandon, ...)
best regards
thierry
On 10/7/24 7:37 PM, Gary Waters wrote:
Hi Thierry,
Ok I ll decrease the timeout to 15 seconds then.
Reducing the size of the logs will help.
Which log and how do I do this ?
Thanks Marc and Theirry!
-Gary
On 10/7/24 00:26, Thierry Bordaz wrote:
Hi,
Those slap_poll error means that the server was
unable to send back PDU to the client. It can
occur if the client sends a request and does not
read fast enough the results. The timeout is high
30s (30000), could it be that the problem is on
the client side (app) ?
I suggest that you focus on the timestamp when the
application reports a failure. Then look in the
access/error logs from 1-3min before and after the
time of the failure. Logconv from that limited
scope will be more helpful than a global one.
The pattern looks to be an app opens a connection,
switch to secure connection (start-tls), issue 6-8
SRCH then close. etime/wtime/optime looks fine but
as it is an average (over 1M op) it is not
helpful. Reducing the size of the logs will help.
I found interesting the abandon op as it is
possibly related to a performance issue.
best regards
thierry
On 10/4/24 11:54 PM, Gary Waters via 389-users wrote:
Hi Marc,
I have made nsslapd-listen-backlog-size to 512.
For the ioblocktimeout, I increased it because
of an error I was seeing:
[30/Sep/2024:16:26:55.987681019 -0700] - ERR -
slapd_poll - (743) - Timed out
[30/Sep/2024:16:34:49.646922635 -0700] - ERR -
slapd_poll - (568) - Timed out
Googling stated that I should increase the
ioblocktimeout. So I bumped it up from 20000
to 30000.
Since then, those slapd_poll timed out errors
have not occurred. Should I have changed
something else?
What should I increase these to?
net.core.somaxconn = 4096
net.ipv4.tcp_max_syn_backlog = 4096
Thanks so much for your help!
-Gary
On 10/4/24 11:55, Marc Sauton wrote:
tune up nsslapd-listen-backlog-size
and verify the net.core.somaxconn
and net.ipv4.tcp_max_syn_backlog are high
enough ( sysctl -a )
possibly tune down
the nsslapd-ioblocktimeout value
Thanks,
M.
On Fri, Oct 4, 2024 at 11:06 AM
gwaters-web--- via 389-users
<389-users@lists.fedoraproject.org> wrote:
Hello,
We are experiencing a new issue since
we upgraded from 389-ds-base from
1.4~ish to 2.0.15 on RHEL 8. I couldnt
figure how to fix it, so I
switched to RHEL9 and are on 2.4.5-9.
The issue is during a performance load
test of a web application. The
app logs into a website and does some
things that searches against ldap,
and does some transactions. This app
has been performing fine for years,
the app has changed so it could be
something there, but I am not sure
about that because of the percentage
of the traffic that is successful.
The errors for the web app are "Can't
contact Ldap Server" and sometimes
"Can't contact LDAP server. Start TLS
request accepted.Server willing to
negotiate SSL. (0xFFFF [-1])". Out of
the 128k connections below, these
errors will happen like 5 or 6 times,
so its wildly inconsistent and random.
I did a logconv analysis with 6 hours
of a day of testing, see below.
One thing that really stood out to me
was the peak concurrent
connections = 22.. That peak is so
low, I dont know how these errors are
happening.
I dont see any errors in the access
log ( grepping for err=1).
I looked for cache warnings/errors in
the access/errors logs, but didnt
find any. I dont see things like
unavailable connections in the access
logs.
Suggestions on what to change or look
for in the logs ?
Thanks,
Gary
information:
Machine Size: 16G of ram, 4 core AMD
(its an EC2.m5.large, gp3 disk type)
kernel:
Linux 5.14.0-427.35.1.el9_4.x86_64 #1
SMP PREEMPT_DYNAMIC
packages:
389-ds-base-libs-2.4.5-9.el9_4.x86_64
389-ds-base-2.4.5-9.el9_4.x86_64
single instance of dirsrv running
dirsrv modifcations from default:
nsslapd-logging-backend: dirsrv-log,syslog
nsslapd-maxdescriptors: 8192
nsslapd-listen-backlog-size: 256
nsslapd-allow-hashed-passwords: on
nsslapd-idletimeout: 30
nsslapd-ioblocktimeout: 30000
nsslapd-sizelimit: -1
nsslapd-auditlog-logging-enabled: off
nsslapd-lookthroughlimit: -1
dirsrv.systemd:
limitNOFILE=8192
>Total Log Lines Analszed: 2694287
>
>
>
> ---------- Access Log Output
------------
>
> Start of Logs:
26/Sep/2024:10:07:32.089983378
> End of Logs:
26/Sep/2024:15:54:29.895403688
>
> Processed Log Time: 5 Hours, 46
Minutes, 57.805426688 Seconds
>
> Restarts: 0
> Secure Protocol Versions:
> - TLS1.2 128-bit AES-GCM (123117
connections)
>
> Peak Concurrent Connections: 22
> Total Operations: 1097043
> Total Results: 1097044
> Overall Performance: 100.0%
>
> Total Connections: 128646
(6.18/sec) (370.78/min)
> - LDAP Connections: 128646
(6.18/sec) (370.78/min)
> - LDAPI Connections: 0
(0.00/sec) (0.00/min)
> - LDAPS Connections: 0
(0.00/sec) (0.00/min)
> - StartTLS Extended Ops:
123116 (5.91/sec) (354.84/min)
>
> Searches: 845279 (40.60/sec)
(2436.22/min)
> Modifications: 0
(0.00/sec) (0.00/min)
> Adds: 0 (0.00/sec)
(0.00/min)
> Deletes: 0 (0.00/sec)
(0.00/min)
> Mod RDNs: 0 (0.00/sec)
(0.00/min)
> Compares: 0 (0.00/sec)
(0.00/min)
> Binds: 128647 (6.18/sec)
(370.78/min)
>
> Average wtime (wait time): 0.001560856
> Average optime (op time): 0.003310453
> Average etime (elapsed time):
0.004868040
>
> Multi-factor Authentications: 0
> Proxied Auth Operations: 0
> Persistent Searches: 0
> Internal Operations: 0
> Entry Operations: 0
> Extended Operations: 123116
> Abandoned Requests: 1
> Smart Referrals Received: 0
>
> VLV Operations: 0
> VLV Unindexed Searches: 0
> VLV Unindexed Components: 0
> SORT Operations: 0
>
> Entire Search Base Queries: 0
> Paged Searches: 0
> Unindexed Searches: 0
> Unindexed Components: 0
> Invalid Attribute Filters: 0
> FDs Taken: 128646
> FDs Returned: 129318
> Highest FD Taken: 968
>
> Broken Pipes: 0
> Connections Reset By Peer: 0
> Resource Unavailable: 0
> Max BER Size Exceeded: 0
>
> Binds: 128647
> Unbinds: 119206
> -------------------------------------
> - LDAP v2 Binds: 0
> - LDAP v3 Binds: 128647
> - AUTOBINDs(LDAPI): 0
> - SSL Client Binds: 0
> - Failed SSL Client Binds: 0
> - SASL Binds: 0
> - Dir
--
_______________________________________________
389-users mailing list --
389-users@lists.fedoraproject.org
To unsubscribe send an email to
389-users-le...@lists.fedoraproject.org
Fedora Code of Conduct:
https://docs.fedoraproject.org/en-US/project/code-of-conduct/
<https://urldefense.com/v3/__https:/docs.fedoraproject.org/en-US/project/code-of-conduct/__;!!JE2nyJ8!1qCobdltMGmX_XrFdPGoEKXfZdGVOi6A5VWjbWtmSJ7AwkqY-PydSmvJfs-4UYWfupW5of5u87v7mBMWQCBDEiq_mj_I$>
List Guidelines:
https://fedoraproject.org/wiki/Mailing_list_guidelines
<https://urldefense.com/v3/__https:/fedoraproject.org/wiki/Mailing_list_guidelines__;!!JE2nyJ8!1qCobdltMGmX_XrFdPGoEKXfZdGVOi6A5VWjbWtmSJ7AwkqY-PydSmvJfs-4UYWfupW5of5u87v7mBMWQCBDEsTfSxSj$>
List Archives:
https://lists.fedoraproject.org/archives/list/389-users@lists.fedoraproject.org
<https://urldefense.com/v3/__https:/lists.fedoraproject.org/archives/list/389-users@lists.fedoraproject.org__;!!JE2nyJ8!1qCobdltMGmX_XrFdPGoEKXfZdGVOi6A5VWjbWtmSJ7AwkqY-PydSmvJfs-4UYWfupW5of5u87v7mBMWQCBDEslJO53N$>
Do not reply to spam, report it:
https://pagure.io/fedora-infrastructure/new_issue
<https://urldefense.com/v3/__https:/pagure.io/fedora-infrastructure/new_issue__;!!JE2nyJ8!1qCobdltMGmX_XrFdPGoEKXfZdGVOi6A5VWjbWtmSJ7AwkqY-PydSmvJfs-4UYWfupW5of5u87v7mBMWQCBDEvlOa8tQ$>
--
_______________________________________________
389-users mailing list -- 389-users@lists.fedoraproject.org
To unsubscribe send an email to 389-users-le...@lists.fedoraproject.org
Fedora Code of Conduct:
https://docs.fedoraproject.org/en-US/project/code-of-conduct/
List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
List Archives:
https://lists.fedoraproject.org/archives/list/389-users@lists.fedoraproject.org
Do not reply to spam, report it:
https://pagure.io/fedora-infrastructure/new_issue
