If you are planning to deploy HCL Sametime Community service in a cluster or HA architecture, setting a Community ID is a must.
Ideally, this should be an FQDN used for accessing the Community servers, something which is easy to remember, and your users can relate to. So, think ahead and use a name that can be used to access the service externally and internally, I would never use the hostname of the Sametime Community server, in most cases, this is hard to remember and can’t be used to access the service over the internet. A “nice” and simple DNS alias like “chat.company.com” is generally the best way to go.
This is especially important when setting up an HA environment, in this case, you also must make sure that the FQDN used, points to the Load Balancer. The consequences for not doing this, in a HA environment, can be catastrophic. In an event of the failover, the Sametime Embedded or Connect client may recognize the server failing over to, as a member of a different community. This would result, among other issues, in not displaying the user’s Sametime contact list.
The Community ID can be set via “sametime.ini” and the process is quite simple, as described in the official product documentation.