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<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US">I’m pretty sure that ntp info indicates ntp is not working. reach=0 so no successful connections in many cycles.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US"><a href="https://www.linuxjournal.com/article/6812">https://www.linuxjournal.com/article/6812</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US">Gareth
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt">From:</span></b><span lang="EN-US" style="font-size:11.0pt"> slurm-users <slurm-users-bounces@lists.schedmd.com>
<b>On Behalf Of </b>Barbara Krašovec<br>
<b>Sent:</b> Wednesday, 28 October 2020 5:41 PM<br>
<b>To:</b> slurm-users@lists.schedmd.com<br>
<b>Subject:</b> Re: [slurm-users] [External] Munge thinks clocks aren't synced<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<pre><o:p> </o:p></pre>
<p>Rewound credential error means that credential appears to have been encoded by more than TTL seconds in the future (default munge TTL is 5 minutes). So the clock on the decoding host is slower than on the encoding host. You can try to run munge with a different
TTL (munge -t) just to verify if it is a time sync issue. Also check the time on the munge.key.<o:p></o:p></p>
<p>I don't think it's related to the new subnet.<o:p></o:p></p>
<p>Cheers,<o:p></o:p></p>
<p>Barbara<o:p></o:p></p>
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<p class="MsoNormal">On 10/27/20 9:58 PM, Gard Nelson wrote:<o:p></o:p></p>
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<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal"><span style="font-size:11.0pt">Thanks for your help, Prentice.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Sorry, yes – centos 7.5 installed on a fresh HDD. I rebooted and checked that chronyd is disabled. ntpd is running. The rest of the cluster uses centos 7.5 and ntp so it’s possible, although maybe not ideal.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">I’m running ntpq on the new compute node. It is looking to the slurm head node which is also set up as the ntp server. Here’s the output:</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Courier"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Courier">[root ~]# ntpq -p</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Courier"> remote refid st t when poll reach delay offset jitter</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Courier">==============================================================================</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Courier">HEADNODE_IP .XFAC. 16 u - 1024 0 0.000 0.000 0.000</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">It was a bit of a pain to get set up. The time difference was several hours so ntp would have taken ages to fix on its own. I have used ntpdate successfully on the existing compute nodes, but got a “no server
suitable for synchronization found” error here. ‘ntpd -gqx’ timed out. So in order to set the time, I had to point ntp to the default centos pool of ntp servers to set the time and then point it back to the headnode. After that, ‘ntpd -gqx’ ran smoothly and
I assume (based on the ntpq output) that it worked. Running ‘date’ on the new compute and existing head node simultaneously returns the same time to within ~1 sec rather than the 7:30 gap from the log file.
</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Not sure if it’s relevant to this problem, but the new compute node is on a different subnet connected to a different port than the existing compute nodes. This is the first time that I’ve set up a node on
a different subnet. I figured it be simple to point slurm to the new node, but I didn’t anticipate ntp and munge issues.</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Thanks,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Gard</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="color:black">From: </span></b><span style="color:black">slurm-users
<a href="mailto:slurm-users-bounces@lists.schedmd.com"><slurm-users-bounces@lists.schedmd.com></a> on behalf of Prentice Bisbal
<a href="mailto:pbisbal@pppl.gov"><pbisbal@pppl.gov></a><br>
<b>Reply-To: </b>Slurm User Community List <a href="mailto:slurm-users@lists.schedmd.com">
<slurm-users@lists.schedmd.com></a><br>
<b>Date: </b>Tuesday, October 27, 2020 at 12:22 PM<br>
<b>To: </b><a href="mailto:slurm-users@lists.schedmd.com">"slurm-users@lists.schedmd.com"</a>
<a href="mailto:slurm-users@lists.schedmd.com"><slurm-users@lists.schedmd.com></a><br>
<b>Subject: </b>Re: [slurm-users] [External] Munge thinks clocks aren't synced</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
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<p>You don't specify what OS or version you're using. If you're using RHEL 7 or a derivative, chrony is used by default over ntpd, so there could be some confusion between chronyd and ntpd. If you haven't done so already, I'd check to see which daemon is actually
running on your system. <o:p></o:p></p>
<p>Can you share the complete output of ntpq -p with us, and let us know what nodes the output is from? You might want to run 'ntpdate' before starting ntpd. If the clocks are too far off, either ntpd won't correct the time, or it will take a long time. ntpdate
immediately syncs up the time between servers. <o:p></o:p></p>
<p>I would make sure ntpdate is installed and enabled, then reboot both compute nodes. This will make sure that ntpdate is called at startup before ntpd, and will then make sure all start using the correct time.
<o:p></o:p></p>
<p>--<br>
Prentice<o:p></o:p></p>
<p> <o:p></o:p></p>
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<p class="MsoNormal">On 10/27/20 2:08 PM, Gard Nelson wrote:<o:p></o:p></p>
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<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal"><span style="font-size:11.0pt">Hi everyone,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">I’m adding a new node to an existing cluster. After installing slurm and the prereqs, I synced the clocks with ntpd. When I run ‘ntpq -p’, I get 0.0 for delay, offset and jitter. (the slurm head node is also
the ntp server) ‘date’ also gives me identical times for the head and compute nodes. However, when I start slurmd, I get a munge error about the clocks being out of sync. From the slurmctld log:</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">[2020-10-27T11:02:06.511] node NEW_NODE returned to service</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">[2020-10-27T11:02:07.265] error: Munge decode failed: Rewound credential</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">[2020-10-27T11:02:07.265] ENCODED: Tue Oct 27 11:09:45 2020</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">[2020-10-27T11:02:07.265] DECODED: Tue Oct 27 11:02:07 2020</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">[2020-10-27T11:02:07.265] error: Check for out of sync clocks</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">[2020-10-27T11:02:07.265] error: slurm_unpack_received_msg: MESSAGE_NODE_REGISTRATION_STATUS has authentication error: Rewound credential</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">[2020-10-27T11:02:07.265] error: slurm_unpack_received_msg: Protocol authentication error</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">[2020-10-27T11:02:07.275] error: slurm_receive_msg [HEAD_NODE_IP:PORT]: Unspecified error</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">I restarted ntp, munge and the slurm daemons on both nodes before this last error was generated. Any idea what’s going on here?</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt"> </span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Thanks,</span><o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Gard</span><o:p></o:p></p>
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</blockquote>
<pre>-- <o:p></o:p></pre>
<pre>Prentice Bisbal<o:p></o:p></pre>
<pre>Lead Software Engineer<o:p></o:p></pre>
<pre>Research Computing<o:p></o:p></pre>
<pre>Princeton Plasma Physics Laboratory<o:p></o:p></pre>
<pre><a href="https://urldefense.com/v3/__http:/www.pppl.gov__;!!LM3lv1w8qtQ!AUViCRtpIXKV37Z4WGp5j64ppClYVIuzUEXXvfoDHHD_tVjDVMA9b2gBHtaWUHsEPdvmkQ$">http://www.pppl.gov</a><o:p></o:p></pre>
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