How does InterSystems IRIS determine it's hostname for $System / $System.INetInfo.LocalHostName()?

We have a UNIX VM with an InterSystems IRIS instance which we cloned for testing purposes, and we have found that $System (which is used for self-identification in email notifications) is still showing the hostname of the original VM, rather than the hostname of the cloned VM.  This is coming from $System.INetInfo.LocalHostHame().

Does anyone know what you need to change on a UNIX clone in order for it to display the appropriate new host name in $System?