Database Communication Error in CUCM 7

First time I ran into this issue was back when I was changing the IP addresses of my CUCM Pub and Sub to match the IPX workbooks. While building the VMs, I did not realize and assigned the home network IP subnet 192.168.x.x to these servers. When I changed the IPs, all hell broke lose and I started seeing this error.

That was a couple of months ago and after giving up I went ahead and redid the VMs. Well I had to change IPs again to move from IPX to INE topology and made sure that I did everything right.

Here is the correct order in which you SHOULD change IP addresses of both Publisher and Subscriber.

Change Server IP addresses on Publisher

  • Go to System > Server and click “Find”.
  • You will see the IP addresses of both Publisher and Subscriber.
  • Change them to the new IP addresses and save.

Change Server IP addresses on Subscriber

  • Go to System > Server and click “Find”.
  • You will see the IP addresses of both Publisher and Subscriber.
  • Change them to the new IP addresses and save.

Change the IP address of Publisher using CLI/SSH

  • Login to SSH and use “set network ip eth0 IP ADDRESS” to enter the new IP address.
  • System will not reboot.
  • If going to a different subnet, change the default gateway using “set network gateway” command.
  • At this point you are doen with the Publisher and you should shut it down using “utils system shutdown”.

Change the IP address of Subscriber using CLI/SSH

  • Login to SSH and use “set network ip eth0 IP ADDRESS” to enter the new IP address.
  • System will not reboot.
  • If going to a different subnet, change the default gateway using “set network gateway” command.
  • At this point you are doen with the Subscriber and you should shut it down using “utils system shutdown”.

Bring up the Servers

  • Power on the Publisher and wait until you can login to the admin page.
  • Power on the Subscriber and wait until you can login to the admin page.

If you follow this process step by step, you shouldnt really get into any issues. But just in case you did not follow the steps you can troubleshoot using the following steps.

  • Use “show network cluster” command to make sure that both Publisher and Subscriber have the same IP addresses.
  • Use “show network ip eth0″ to make sure that the ip address and gateway are correct.
  • Go to System > Cisco Unified CM and make sure that both Publisher and Subscriber are present and show the correct IP and Hostname.

In my case the error “Database Communication Error” was showing up when I was trying to login to the Subscriber Admin page.  I made sure I followed the steps on the Subscriber and after a reboot everything was fine. Problem occurs when the Subscriber is not able to reach the Publisher so make sure you follow the steps in the correct order.

About CCIETalk

An Experienced Unified Communications Engineer Specializing in Cisco, Riverbed, VMware and Relevant Technologies. CCIE Voice, CCNA, CCDA, CCNP, CCDP, CCIP, RCSA.

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