Updating NTP server on Call Manager

[s.shen]

Hello, I'm looking to update our NTP server on our call manager. I've read instructions on how to add it and they say to restart the NTP service. Should this be done when no one is using the system? I'm worried it might affect network connectivity.

utils ntp server add x.x.x.x

utils ntp restart

After completing this do I need to do any other configurations either in CLI or on the web interface to get this working?

We are getting the errors below which caused me to look into the issue.

WARNING: NTP server unreachable (on the login page of CUCM web interface)

admin:utils diagnose test

Log file: platform/log/diag2.log

Starting diagnostic test(s)
===========================
test - disk_space : Passed (available: 1579 MB, used: 12577 MB)
skip - disk_files : This module must be run directly and off hours
test - service_manager : Passed
test - tomcat : Passed
test - tomcat_deadlocks : Passed
test - tomcat_keystore : Passed
test - tomcat_connectors : Passed
test - tomcat_threads : Passed
test - tomcat_memory : Passed
test - tomcat_sessions : Passed
skip - tomcat_heapdump : This module must be run directly and off hours
test - validate_network : Error, intra-cluster communication is broken, unabl e to connect to [172.17.2.36] Error, intra-cluster c ommunication is broken, unable to connect to [172.17.4.36]
test - raid : Passed
test - system_info : Passed (Collected system information in diagnostic log)
test - ntp_reachability : Failed
The host 172.17.2.1 is not reachable, or it's NTP service is down.

admin:utils ntp status
ntpd (pid 12214) is running...

remote refid st t when poll reach delay offset jitter
==============================================================================
172.17.2.1 .INIT. 16 u 4 1024 0 3.030 -0.044 0.000

I'm wondering why it's point to 172.17.2.1 when that isn't our actual NTP server (172.17.2.1 device is configured to point to the actual NTP server, but I don't see why our call manager shouldn't be pointed to it directly).

Thanks for any help, much appreciated!

[Dennis Mink]

 it will need to be set up as an NTP server, if its a cisco switch/router depending on what device it is (ntp master off the top of my head)

also can you ping the 172.17.2.1 from cucm?

[s.shen]

Hi, thank you. Yes I can ping that address from CUCM, it is directly connected I believe. After looking at 17.17.2.1 NTP configurations it is pointing to our actual NTP server 172.16.1.1 (using an example IP). Is it possible that somehow 17.17.2.1 was forwarding that NTP information to CUCM? I am not sure why we all of a sudden got this NTP warning though so no changes have been made. How would you recommend I proceed?

[Jaime Valencia]

CUCM doesn't randomly choose an NTP, someone configured CUCM to use that IP as the NTP. CUCM validates the NTP is working in order for it to be configured, it won't accept a bogus IP that doesn't provide NTP.

The change is quite easy, you can do it via CLI and be done in less than 5 minutes.

[s.shen]

Thank you, I guess where I'm getting confused is why is why is this error coming up all of a sudden when no changes have been made. Would you recommend pointing CUCM to our actual NTP server? Do you know if there would be any network interference when changing NTP servers?

[Jaime Valencia]

You need to use a reliable NTP, if the one you're pointing to is not reliable, then point to the real NTP.

No network services will be affected by adding/removing/restarting NTP.

[Justin Ferello]

Jaime,

Doesn't changing the NTP nullify your licensing too?  He will have to request new licenses, right?

[Jaime Valencia]

Only for 8.x and below where we used a licensing MAC.

NTP has no relationship with licensing for releases that use ELM/PLM/Smart Licensing 

[Justin Ferello]

That's odd, we had to update the NTP in our 10.0 or 10.5 deployment and it invalidated our licenses...

[Jaime Valencia]

See this bug.

PLM should warn if license request attempted with dynamic MAC address

CSCul66335

I changed the NTP for my 10.5 and 11.5 in January and I had to do absolutely nothing related to my licenses because of the change.

[Justin Ferello]

Jaime,
Thanks for the bug. Good to know! I guess since our PLM and Pub are on the same box/host that changing the NTP must have changed the MAC of the Ethernet interface?
Is it still best practice to static assign the MAC for the PLM interface? Is there a certain number that people use?

[Jaime Valencia]

I'm using a co-res PLM in my lab, so, no, changing the NTP does NOT change the VM MAC address.

PLM install guide has the static MAC note.

https://pubs.vmware.com/vsphere-4-esx-vcenter/index.jsp?topic=/com.vmware.vsphere.server_configclassic.doc_41/esx_server_config/advanced_networking/c_setting_up_mac_addresses.html

[telus-cvms]

Is there any documentation in regards with that ? 

I.e. What changes will require a licence rehost for any Cisco UC apps ?

NTP? 

Certificate ? 

I tried to search for an official doc and wasn't able to. 

Thx in advance.