Ran into this bug today. Went to a pair of Nexus 5500s to debug a vPC link and noticed the timestamps were off. I thought that was odd. I tried show ntp peer-status and received no output in return, which I thought was even more odd. I poked at NTP for a while and decided it had to be a bug. I found the bug in the release notes and it was fixed in 5.2(1)N1(6). Here’s the Cisco bug report:

Symptom:
Nexus 5k acting as an NTP Client can’t sync with any NTP server(s).
when issuing a “show ntp peer-status” or a “show ntp peers” it does not display any of the servers/peers configured.

Conditions:
Nexus 5500/5000 running 5.2(1)N1(5).

Workaround:
Proactive workaround to prevent from this issue is none.
Reactive workaround to recover this issue is below. However, after reloading system, same issue may happen again.

#conf t
#clock protocol none
#clock protocol ntp
#copy run start


Fun. At least it can be fixed without reloading, which is a good thing in a data center switch.

FIN