Nexus 5K Unexpected Reboots / System Hang on show run — NX-OS 7.3(2)N1

[afikaLuke]

Hey all,

we’re currently facing a critical issue with one of our Cisco Nexus 5000 series switches in production (running NX-OS 7.3 N1). The switch randomly reboots or completely hangs during basic commands like show running-config. When issuing that command, sometimes the switch doesn’t respond at all and ends up rebooting itself without logging anything significant beforehand.

This has started happening frequently and causes serious disruptions in our environment.

We’ve checked:

• Power supplies — both are fine

• Temperature — no issues

• No signs of memory exhaustion or CPU spikes before the crash

• No recent firmware updates or configuration changes that we can trace it back to

We are running FEX (100) and using multiple port-channels for uplinks and FEX connectivity. Nothing unusual in the config — I’ve attached/redacted a relevant portion of the running config to this post (minus any sensitive info).

Our default route is via:

ip route 0.0.0.0/0 192.168.42.254

And the management VRF and interface is configured like this:

interface Vlan42
no shutdown
management
ip address 192.168.42.240/24

Boot image:

boot kickstart bootflash:/n5000-uk9-kickstart.7.3.2.N1.1.bin
boot system bootflash:/n5000-uk9.7.3.2.N1.1.bin

Is there a known issue with this specific NX-OS version that could lead to such unstable behavior? Would upgrading to a later 7.x release or switching to a more stable long-term release be advisable?

Appreciate any insight or TAC case pointers if someone experienced the same thing.

Thanks in advance.

[marce1000]

       >... Would upgrading to a later 7.x release or switching to a more stable long-term release be advisable?
       It certainly would , since it's difficult to determine the complex background for such a problem, I would
       always upgrade to the latest advisory release :  7.3(13)N1(1) 

       You can configure a syslog server on the Nexus for collecting logs; then sometimes last gasp logging
       could provide insights as to why the device is crashing

       As far as existing issues ; in the bug search tool, you can look for a model and affecting releases with issues.
       Doubt it will give anything useful; I made an attempt on it for your nexus : 
        https://bst.cloudapps.cisco.com/bugsearch?pf=prdNm&sb=afr&prdNam=Cisco%20Nexus%205596UP%20Switch&kw=*&bt=custV&rls=7.3(2)N1(1)
       You can tweak these parameters for further insights. But I don't expect too much from it.

                     Baseline action = upgrade to   7.3(13)N1(1) 

  M.

[afikaLuke]

Thanks a lot for the detailed answer, much appreciated!

One quick follow-up: since the Nexus 5596UP is already quite an old platform, where would I be able to download the 7.3(13)N1(1) NX-OS image?
I had a look in the usual places on the Cisco Software Download portal, but I’m not sure if it’s still publicly available or requires a special service contract.

Thanks again for the support!

[marce1000]

  @afikaLuke   FYI : https://software.cisco.com/download/home/283757883/type/282088129/release/7.3(13)N1(1)
                                        But you will always need a Service Contract for downloading software  .

  M.