Nexus Switch - Power supply not recognized

Power supply shown as ‘None’

One of my customers change the power cable at one of his Nexus 93180yc-fx3 switches. After that, the Switch started alerting that the power supply was down. The fact that the power supply was down was shown on the Nexus Switch.

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nexus# show environment power 
Power Supply:
Voltage: 12 Volts
Power                      Actual             Actual        Total
Supply    Model            Output             Input        Capacity     Status
                           (Watts )           (Watts )     (Watts )
-------  ----------  ---------------  ------  ----------  --------------------
1        NXA-PAC-650W-PE       120 W              135 W       650 W      Ok
2        NXA-PAC-650W-PE         0 W                0 W         0 W    None

The strange part was that the power supply itself was still powered up (green led), and everything looked good physically. So this was a software issue.

This Incident happened on NX-OS Version 10.2.5, which is currently (7th of July, 2023) the recommended release for this platform.

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nexus# show ver
Cisco Nexus Operating System (NX-OS) Software
TAC support: http://www.cisco.com/tac
Copyright (C) 2002-2023, Cisco and/or its affiliates.
All rights reserved.
The copyrights to certain works contained in this software are
owned by other third parties and used and distributed under their own
licenses, such as open source. This software is provided "as is," and unless
otherwise stated, there is no warranty, express or implied, including but not
limited to warranties of merchantability and fitness for a particular purpose.
Certain components of this software are licensed under
the GNU General Public License (GPL) version 2.0 or
GNU General Public License (GPL) version 3.0  or the GNU
Lesser General Public License (LGPL) Version 2.1 or
Lesser General Public License (LGPL) Version 2.0.
A copy of each such license is available at
http://www.opensource.org/licenses/gpl-2.0.php and
http://opensource.org/licenses/gpl-3.0.html and
http://www.opensource.org/licenses/lgpl-2.1.php and
http://www.gnu.org/licenses/old-licenses/library.txt.

Software
  BIOS: version 01.08
  NXOS: version 10.2(5) [Maintenance Release]
  BIOS compile time:  05/06/2022
  NXOS image file is: bootflash:///nxos64-cs.10.2.5.M.bin
  NXOS compile time:  3/10/2023 12:00:00 [03/03/2023 13:00:11]

Hardware
  cisco Nexus9000 C93180YC-FX3 Chassis
  Intel(R) Xeon(R) CPU D-1526 @ 1.80GHz with 16322576 kB of memory.
  Processor Board ID SERIAL
  Device name: nexus
  bootflash:  115805708 kB

Kernel uptime is 49 day(s), 22 hour(s), 18 minute(s), 42 second(s)

Last reset at 609732 usecs after Thu May 18 10:23:06 2023
  Reason: Reset due to upgrade
  System version: 9.3(9)
  Service:

plugin
  Core Plugin, Ethernet Plugin

Active Package(s):

Log msg: %PLATFORM-4-PFM_PS_RED_MODE_CHG

Besides the alerting regarding the power state itself, the Switch also produced endless log messages regarding the power redundancy configuration.

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2023 Jul  7 08:37:25 nexus %PLATFORM-4-PFM_PS_RED_MODE_CHG: Power redundancy configured mode changed to ps-redu
ndant (message repeated 62 times)
2023 Jul  7 08:38:25 nexus %PLATFORM-4-PFM_PS_RED_MODE_CHG: Power redundancy configured mode changed to ps-redu
ndant (message repeated 60 times)
2023 Jul  7 08:39:27 nexus %PLATFORM-4-PFM_PS_RED_MODE_CHG: Power redundancy configured mode changed to ps-redu
ndant (message repeated 62 times)
2023 Jul  7 08:40:28 nexus %PLATFORM-4-PFM_PS_RED_MODE_CHG: Power redundancy configured mode changed to ps-redu
ndant (message repeated 61 times)
2023 Jul  7 08:41:29 nexus %PLATFORM-4-PFM_PS_RED_MODE_CHG: Power redundancy configured mode changed to ps-redu
ndant (message repeated 61 times)
2023 Jul  7 08:42:30 nexus %PLATFORM-4-PFM_PS_RED_MODE_CHG: Power redundancy configured mode changed to ps-redu
ndant (message repeated 61 times)
2023 Jul  7 08:43:03 nexus %PLATFORM-4-PFM_PS_RED_MODE_CHG: Power redundancy configured mode changed to ps-redu
ndant (message repeated 32 times)

These messages were shown, even though the Switch itself had the power redundancy configured adequately, as shown in the output below.

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nexus# show run all | i "power red"
power redundancy-mode ps-redundant

I couldn’t find a bug in the bug tool from Cisco, but it was pretty obvious that something is off here.

How to fix the power supply shown as ‘None’?

The solution to this issue is easy but also annoying. You have to reseat the Power Supply (Remove & Replug). Everything was back to regular operation after we did that at the Nexus Switch of the Customer.

Logs during the reseat of the Power Supply.

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2023 Jul 11 14:11:49 nexus %PLATFORM-2-PS_REMOVE: Power supply 2 removed (Serial number SERIAL)
2023 Jul 11 14:11:49 nexus %PLATFORM-2-PS_CAPACITY_CHANGE: Power supply PS2 changed its capacity. possibly due to On/Off or power cable removal/insertion (Serial number SERIAL)
2023 Jul 11 14:11:49 nexus %PLATFORM-4-PFM_PS_RED_MODE_CHG: Power redundancy configured mode changed to ps-redundant
2023 Jul 11 14:11:58 nexus %PLATFORM-4-PFM_PS_RED_MODE_CHG: Power redundancy configured mode changed to ps-redundant (message repeated 1 time)
2023 Jul 11 14:11:58 nexus %PLATFORM-5-PS_STATUS: PowerSupply 2 current-status is PS_SHUT
2023 Jul 11 14:11:58 nexus %PLATFORM-2-PS_FAIL: Power supply 2 failed or shut down (Serial number SERIAL)
2023 Jul 11 14:11:58 nexus %PLATFORM-4-PFM_PS_RED_MODE_CHG: Power redundancy configured mode changed to ps-redundant
2023 Jul 11 14:12:02 nexus %PLATFORM-4-PFM_PS_RED_MODE_CHG: Power redundancy configured mode changed to ps-redundant (message repeated 2 times)
2023 Jul 11 14:12:02 nexus %PLATFORM-5-PS_FOUND: Power supply 2 found (Serial number SERIAL)
2023 Jul 11 14:12:02 nexus %PLATFORM-2-PS_OK: Power supply 2 ok (Serial number SERIAL)
2023 Jul 11 14:12:02 nexus %PLATFORM-5-PS_STATUS: PowerSupply 2 current-status is PS_OK
2023 Jul 11 14:12:02 nexus %PLATFORM-2-PS_FANOK: Fan in Power supply 2 ok
2023 Jul 11 14:12:02 nexus %PLATFORM-2-PS_CAPACITY_CHANGE: Power supply PS2 changed its capacity. possibly due to On/Off or power cable removal/insertion (Serial number SERIAL)
2023 Jul 11 14:12:02 nexus %PLATFORM-4-PFM_PS_RED_MODE_CHG: Power redundancy configured mode changed to ps-redundant
2023 Jul 11 14:12:02 nexus %PLATFORM-2-PS_RED_MODE_RESTORED: Power redundancy operational mode changed to configured mode