adding 2 subscribers in an existing cucm cluster impact?

[monasir]

We are going to add 2 cucm subscribers in an existing cucm cluster  ( v 10.5.1 )
Is there something that  i need to take care of besides of doing this action after hours?

Because i've understood that if you add a subscriber to an cluster all the  active phones will have a reset.

What about firmware etc?

[Rajan]

Hi,

No issues if you plan the following properly:

- this new subscriber wont be used for registering endpoints until you add it in the callmanager group 

- Add the subscriber in system --> Server first and then start installing

- Once the subscriber is up and the DB replication is fine, point the new sub in ccm group as needed and then reset the endpoints using them so that they will register in the configured order

Thanks,

Rajan

[Aman Soi]

Do check for NTP synchronization from CUCM PUB before starting installation of Subs.

regds,

aman

[Deepak Rawat · Accepted solution]

Because i've understood that if you add a subscriber to an cluster all the  active phones will have a reset.

Your understanding is correct since starting version 8.6 if you add a new subscriber to the cluster, phones will reset and below explains the same

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCub12922/?reffering_site=dumpcr

https://supportforums.cisco.com/document/12563121/clarity-bug-cscub12922-adding-new-subscriber-causes-device-reset

As you have plans to do this in after hours, then you do not need to worry. Secondly regarding the FW, Device packs etc if you have uploaded them to the existing CM servers then you will need to do it manually for the new servers that you are planning to add into the cluster as well. If the existing CM servers do not have any thing uploaded to them in terms of FW, DP, images etc then no need.

Regards

Deepak