RANCID for Cisco Nexus 5K - Be careful with CSCts72635. [EXPLAINED]

Today I’ve added a couple of Nexus 5K switches to RANCID. Doing so I remembered potential issue with older Nexus software version and decided to make a quick note.

It’s related to Cisco bug CSCts72635 that causes Nexus 5K with software older than 5.1(3)N1(1) to reboot after issuing “show version” command after 10240 times. Remember, RANCID executes this command every time to grab software version.

Here are bug details:

Conditions:If callhome is configured and sending alerts (like temperature alarms), the bios_daemon can be triggered in this process. The problem is that bios_daemon opens a file descriptor and it does not close.

“show version” is another way to trigger this.

The problem will occur after 10240 callhome alerts or instances of running “show version”

Known Fixed Releases: 5.1(3)N1(1)

Original post about it is here.

Good luck!

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