Convert Subscriber to Publisher

Unanswered Question
Aug 25th, 2009

Hi,

I have a CUCM 7.x Cluster with one Publisher and two Subscriber. My question is:

Are there any way to convert a CUCM Subscriber to a CUCM Publisher?

How I can convert it? If I have a disaster and my Publisher is down how I can convert one subscriber to publisher and now I have the availability to add new device or make any changes?

Thanks!

Fran

I have this problem too.
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KonradStepniewski Tue, 08/25/2009 - 02:49

As far as i know only way to do it is to reinstall new server with Publisher role. There is no option to convert Sub to Pub.

rob.huffman Tue, 08/25/2009 - 05:15

Hi Fran,

There is no way to have two actual Publishers or to promote a Sub to Pub at this time. But in the newer CUCM versions there is an extra measure of redundancy. Here is the background (there is no way to do this on any CCM version until 6.x)

The configuration database is stored on a publisher server, and a read-only copy is replicated to the subscriber members of the cluster. Changes made on the publisher are communicated to the subscriber databases, ensuring that the configuration is consistent across the members of the cluster, as well as facilitating spatial redundancy of the database.

The publisher server is the only server that has read and write access to the configuration database. When configuration changes are made, other members of the cluster have a read-only copy of the database.

From this CCM SRND;

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/4x/42clproc.html

This changes with the release of CCM 6.x;

In prior versions of Cisco Unified Communications Manager, subscriber servers in the cluster use the publisher database for READ/WRITE access, and only use the local database for READ access when the publisher database cannot be reached. With Cisco Unified Communications Manager Release 6.0, subscriber servers in the cluster READ the local database. DB WRITES happens in both the local database as well as the publisher database, depending on the type of data. DBMS (IDS) replication is used to synchronize the databases on the nodes of the cluster. When recovering from a failover conditions such as loss of WAN connectivity for extended period of time, the Cisco Unified Communications Manager databases need to be synchronized with any changes that may have been made during the outage. This process happens automatically when database connectivity gets restored. This process may take longer over low bandwidth and/or higher delay links.

Database modifications for CallProcessing

User Facing features can be made on subscribers. These include updates for:

Call Forward All (CFA)

Message Waiting Indication (MWI)

Privacy Enable/Disable

Do Not Disturb Enable/Disable (DND)

Extension Mobility Login (EM)

Monitor (for future use, currently no updates at the user level)

Hunt Group Logout

Device Mobility

CTI CAPF status for end users and application users

Credential hacking and authentication

From this 6.x SRND;

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/6x/callpros.pdf

Redundant TFTP Servers are supported and recommended :)

From this CCM SRND;

The TFTP service can be enabled on any server in the cluster. However, in a cluster with more than1250 users, other services might be impacted by configuration changes that can cause the TFTP service to regenerate configuration files. Therefore, Cisco recommends that you dedicate a specific server to the TFTP service in a cluster with more than 1250 users, with Extension Mobility, or with other features that cause configuration changes.

The TFTP server is used by phones and MGCP gateways to obtain configuration information. There is no restriction on the number of servers that can have TFTP service enabled, however Cisco recommends deploying 2 TFTP servers for a large cluster, thus providing redundancy for TFTP service.

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/4x/42clproc.html#wp1051169

Hope this helps!

Rob

Francisco Lucen... Tue, 08/25/2009 - 06:40

Thanks Rob! Great answer!

But on this moment I have up only a CUCM Subscriber 7.1.2 and CUCM Publisher is not alive.

If I understand right... CUCM Subscriber can write to his database and after replicate the changes made to Publisher database but..... Why I cannot add a new H323 Gateway on my CUCM Subscriber? I try to add it but I get this error "Add failed. No INSERT permission."

Do you have any ideas?

Thanks!

rob.huffman Tue, 08/25/2009 - 07:24

Hi Fran,

You are most welcome my friend! Sadly, only these "user facing" changes can be made if the Publisher is "off-line"

User Facing features can be made on subscribers. These include updates for:

Call Forward All (CFA)

Message Waiting Indication (MWI)

Privacy Enable/Disable

Do Not Disturb Enable/Disable (DND)

Extension Mobility Login (EM)

Monitor (for future use, currently no updates at the user level)

Hunt Group Logout

Device Mobility

CTI CAPF status for end users and application users

Credential hacking and authentication

This is why you can't add a Gateway/Phone/CTI-RP etc.

Sorry man!

Rob

Francisco Lucen... Tue, 08/25/2009 - 07:43

Hi Rob,

Thanks my friend!

I think that this is a deficient fact of the cluster service.

If I have a disaster on my Publisher and it's not alive, I'll have to wait until reinstall Publisher server to add any device on any Subscriber.

Thanks for all!

Fran

rob.huffman Tue, 08/25/2009 - 07:55

Hi Fran,

This "abiltiy" to promote a Sub to Pub has been on the "feature request" list for some time now. I wouldn't be surprised to see this functionality in an upcoming CUCM release :)

Cheers!

Rob

Francisco Lucen... Tue, 08/25/2009 - 08:51

Hi Rob,

Ok then I'll review the upcoming CUCM release to find this "feature request".

Regards!

Fran.

ayokunles Tue, 06/18/2013 - 06:23

Just asking, is the feature out yet as I really need to do this like yesterday.

I run a CUCM 7.1

Yes, you can sort of do this, but not at CUCM 7.1.

I've just done a DRS restore of an 8.5 Publisher, and was able to point the restore process at a subscriber database. Worked great. I'm not 100% certain when this feature was added, but I'm pretty certain it was one of the 8.x releases and not in 7.x.

Barry Hesk

Intrinsic Network Solutions

aedamasceno Tue, 06/18/2013 - 06:55

Hello! I don't know if there is a way to do that, but what I know is that you can reinstall the Publisher and try to restore the latest backup. When you restore it, it will see that one of your Subscriber servers is up and it will give you an option to restore the backup using the DB on that Subscriber.

- If you are using UCS, use the same OVA you used before. If you don't, it will create another hash for the license MAC and you will have to rehost the license file.

- If you are using MCS, don't worry with the step above, but make sure you use the same MAC you used for licensing.

- After the whole backup is restored, check the DB replication status. It will be most likely not synchronized.

- use "utils dbreplication stop" in all Subscribers

- then use "utils dbreplication stop" in Publisher and when it is done "utils dbreplication reset all"

- wait and be patient...

I was able to recover from a MAJOR failure in a 7 server cluster. One little subscriber (the warrior subscriber) held the whole system for a few hours while we recovered the other 5 subscribers and the Publisher.

I hope this helps.

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