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Changing the IP for a CUCM cluster

June 18th, 2012 | Posted by Jaime Diez in Cisco

Lately I have had to change the network parameters for a CUCM cluster, this is not a day-to-day task, because of that I going to show you how to change it to avoid any major issue.

As a network parameter, it should be done during a time window out of business hours. As you would do with any other operation, verify the proper operation of the CUCM cluster before make any change, make a backup and have a rollback plan to use in case that something goes wrong.

You will find a guide from Cisco which is a good point to start and covers all the process but I like to have always my own documentation in addition to other, to have my own notes. It helps me to remember important details and issues that I have had, the purpose is to have the whole experience write down.

Let’s start the task, it is very important to follow this order to avoid any error. You will have to request a new license file re-issued  by Cisco to use it after the change. Start making all the changes on the publisher and after that with the subscribers.


Changes from CUCM Administration Web

  1. Go to System -> Server
  2. Change the IP address for each server
  3. The change is replicated to the subscribers, to ensure that, run you can check it one by one or running the following command from the CLI: run sql select name,nodeid from ProcessNode

Changes from CUCM CLI

  1. You have to change from the subscribers the mapping to the publisher IP. It can be done from the CUCM OS Administration or from the CLI running: set network cluster publisher ip ipaddress. This is a repetitive task for each subscriber, so you can use one of the scripts that I posted last week slightly modified.
  2. If you need to change the gateway run: set network gateway gatewayaddress. If you are working with subscribers in the same subnet, you can also use the script from the previous step for this one.
  3. Change the IP address for each node running the following command: set network ip eth0 ipaddress netmask. After issuing this command a restart is required.

If you change the IP address on the CLI before in the CUCM Administration, you will get the “Database Communication Error” which won’t allow you to log in on the system. If it happens, don’t panic, just configure again the exact old network parameters and follow the order explained in this blog post.

Troubleshooting tools

  • show network eth0 –  network configuration
  • show network cluster – state of the nodes in the cluster
  • show perf query class “Number of Replicates Created and State of Replication” – replication status, Replicate_State = 2 means that replication is good.
  • You can also see  the replication status in “Database Summary” from the RTMT tool.

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