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Question about add NTP on CUCM 6.1.3

deniwtonm80
Level 1
Level 1

Hello All,

I´ll pretend to configure the NTP in one of my clusters and some people told me about some problems in this case.

What is the possibility to have a problem when i add a NTP server on a cluster? Anybody know about th DB problems like corrupted information or something like this?

It´s really necessary to restart all nodes in my cluster?  By the way, we use the CUCM 6.1.3.1000-16 . The cluster have 1 publisher, 2 subscribers and 1 TFTP server.

Thanks for the help.

Regards

3 Replies 3

Rob Huffman
Hall of Fame
Hall of Fame

Hi Deniwton,

A Cluster-wide reboot is required when adding or changing NTP servers

Here is the bug you were referencing;

CSCsk70971 Bug Details Bug #4 of 14 | < Previous | Next >

publisher NTP down if configured NTP down or unreliable
Symptom:
The subscriber CUCMs NTP will not sync to the publisher when the external NTP server is unreachable.

Other symptoms include failing database replication or failure to setup database replication. 
15 minutes clock variation on any replication reset will prevent replication setup.

Conditions:
The external NTP server configured on the publisher is unreachable and the cluster has been rebooted. This can also be triggered if there is intermittent connectivity to the publisher. Fluctuation in round trip time to the publisher can also cause this.

Workaround:
Restore connectivity to an external NTP source. Stabilize IP connectivity between publisher and all subscribers in the cluster. Stabilize the round trip time between publisher and all subscribers.
StatusStatus
Fixed             

Severity Severity
3 - moderate

Last Modified Last Modified
In Last Year        

Product Product
Cisco Unified Communications Manager (CallManager)         

Technology Technology


1st Found-In 1st Found-in
5.1(3)
6.1(2)
6.1(3)
7.0(1)
7.0(2)
7.1(2)
6.1(0.9901.388)
6.1(3.1000.9)       
           
Fixed-In Fixed-in
7.1(1.39000.105)
7.1(1.39000.107)
6.1(3.9901.85)
7.1(1.39000.109)
6.1(3.9901.86)
7.1(1.39000.110)
6.1(3.9901.88)
7.1(1.39000.114)
6.1(3.9901.91)
7.1(2.30010.4)
8.0(0.38000.271)
7.1(2.38000.14)
8.0(0.38000.272)
7.1(2.30010.5)
7.1(2.38000.15)
7.1(2.30010.7)
7.1(2.38000.18)
8.0(0.38000.278)
7.1(2.38000.54)
6.1(3.9999.1)
7.1(2.10000.16)
6.1(4.1000.10)
7.1(3.10000.11)
8.0(1.10000.40)

Cheers!

Rob

Hi Rob,

Thanks for your help. I´ll talk with the costumer and i´ll post the results.

Regards!

AFAIK, I have never had to reboot the cluster when adding / deleting NTP server on a server in the cluster. I would be interested to see if there's any documentation mentioning the same.

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.

The defect Rob has mentioned in pretty severe - I would suggest upgrading the servers to a later version (6.1.5 preferrably) if possible, to avoid running into known, severe defects.

Also, keep in mind that Windows NTP servers are not supported with Linux CCM servers

http://tools.cisco.com/Support/BugToolKit/search/getBugDetails.do?method=fetchBugDetails&bugId=CSCte17541

- Sriram

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