NTP problem on Nexus 7000

[e-chuah]

Hi,  I have a N7010 running 5.2(1). There are 3 VDCs - Default, Core and OTV VDCs.  I am not using CFS to distribute NTP.. I am able to ping the NTP server using the mgmt interface as source address Other Catalsyt switches is able to sync with the NTP server.  On the default VDC, i try to configure NTP using the command  feature ntp ntp server 1.1.1.1 use-vrf management prefer ntp server 1.1.1.2 use-vrf management ntp source-interface mgmt0  However, i cannot see any ntp peer using "sh ntp peer", "sh ntp status" also shows nothing.  I try to configure clock protocol on the default vdc to use NTP, but it doesn't help.  Am i missing something ?  Rgds Eng Wee

[Prashanth Krishnappa · Accepted solution]

You can configure NTP only in one VDC and the same clock source will be used for other VDCs. Looks like your NTP

server is reachable in default vRF. If this is the case make sure you do not have "clock protocol ntp vdc x" in default VDC where x is non-default VDC

[e-chuah]

Hi Prkrishn,  THanks for the reply. You are correct. Manage to get it working by some trial and error.  The N7K configuration guide should have explained this more clearly.  Rgds Eng Wee

[andrew.schaefer]

How did you get this to work?  I tried completely turning off the ntp feature on the default vdc so I could set it up on our production VDC.  It still doesn't show any ntp peer servers or respond to requests.

[e-chuah]

Hi Andrew,  configure the below in the default vdc, the "clock protocol ntp vdc x" command is needed only at the default vdc  "clock protocol ntp vdc 1" "ntp server x.x.x.x prefer use-vrf management" "ntp server x.x.x.x use-vrf management" "ntp source-interface  mgmt0"  THis works for me.  Hope it helps. Eng Wee

[andrew.schaefer]

I was able to get the NTP server working in the default vdc, but it won't serve NTP to other clients from the second vdc.  Did you just use the default vdc or a secondary one?

[Oleksandr Nesterov]

Hi Andrew

"clock protocol ntp vdc x" - simply tells to n7k chassis in which vdc he will run ntp client and will receive ntp data.

Only ONE VDC can do that - by default it's 1st vdc .

Then you need to check whether in your vdc ntp feature is not disabled (you can run "feature ntp").

Then enter ntp server configuration (source interface etc) and don't forget stratum.

After that try to configure any ntp client to sync with your server.

HTH

Alex

[andrew.schaefer]

Alex,

The "clock protocol ntp vdc x" command was exactly what I needed.  It is working beautifully from the 2nd vdc now.  Thanks again!!!

ANdrew