Configure NTP server without reboot

[gohlex8848]

Hi Guys,

Is it possible that we configure NTP server on CUCM Pub without rebooting all

the nodes in cluster?

can we like using the the util ntp restart command on CLI to restart the NTP service?

and also for the phone, once we have NTP configured, if we don't reboot the cluster,

do we need to reset/restart the phones or it will get sync with the new timing automatically?

Thanks

Alex

[dijohn]

I have never had to reboot the cluster when adding / deleting  NTP server on a server in the cluster.

You  can SSH to each server and run 'utils ntp status'. The * beside the NTP  server is the one the server is trying to sync to. The output also  shows if the server in synchronized / unsynchronized with the NTP  server.

By  architecture, the Pub is the only server that can be configured with an  external NTP. Any sub in the cluster will sync to the Pub's time, by  design. This is to ensure that all servers have the same time, for  replication to work fine on the cluster.

Please refer http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a0080b2cd0e.shtml .

All SCCP phones will automatically get the time, either at reboot using the StationTimeDateRequest Message in SCCP. This happens once in 24hrs or usually everytime the phone goes offhook and makes a call.

PS: Dont forget to rate the post if its helpful

[gohlex8848]

Hi Dijohn,

Thanks for the reply, so basically what you mean is the "utils ntp restart"

command is not even needed?

Good info on the SCCP phone time update, didn't know it will update without the need of cucm reboot or phone reset.

Alex

[gohlex8848]

Oops, double post

[dijohn]

go ahead add the new NTP Server

try utils ntp status

if that doesn't work try utils ntp restart

but .. ntp usually takes time to synchronize. Give it time.

[gohlex8848]

Hi Dijohn,

Thanks again for the reply, I will give it a try once I got the approval.

But in the case of offset is huge, like 10minutes different with NTP server

will CUCM still sync? Or it will refuse to sync and use local clock instead?

Alex

[dijohn]

IMHO,

Be patient after you configured NTP. It might take hours to synchonize based on the time difference between publisher and NTP source. This works as designed. This is to comply with IETF RFC.

FYI , For any Reliable NTP server, 10 minutes difference between them is unacceptable

[dijohn]

Your action plan in this regard should be

-- Add the NTP Server

-- utils ntp status --->Check Sync status

-- Wait for a while

-- then restart using utils ntp restart

-- Give it some more time

-- utils ntp status

-- LAST resort REBOOT

[gohlex8848]

Hi Dijohn,

Really appreciates your reply, is very helpful of you.

Last question though, because the CUCM is not using any NTP

for the time being, is the offset of CUCM time with NTP time matter?

I remember I read somewhere that we need to set the time of CUCM

as close as NTP time before we add NTP server? Otherwise if offset is huge

the sync will failed?

Corretly me if I'm wrong.

Thanks again Dijohn.

Regards,

Alex

[dijohn · Accepted solution]

Yes.! Make the time on the CUCM and the NTP Server match. This will save

some time in sync. This is the oldest trick in NTP

HTH

PS:Rate the posts if they are helpful. Mark the thread as ANSWERED if we

have answered all your queries

[gohlex8848]

Glad. Thanks dijohn!

[Haitham Hasan Abdel Mohde]

Hi Guys,

From OS Admin guide:

"After deleting, modifying, or adding the NTP server, you must restart all other nodes in the cluster for the changes to take affect."

it may work, but follow the OS guide for guaranteed results

B.R./Haitham

If you find this helpful, Please Rate

[gohlex8848]

Thanks Haitham for the suggestion, I understand that as per Cisco suggestion we should reboot all nodes in the cluster,

however I'm looking for alternative. Currently the cluster is serving quite number of sites, so was trying to avoid bringing

downtime on this.

Cheers