cmapi write the hostname in columnstore.xml
with
socket.gethostbyaddr(hostaddr)[0] or socket.gethostbyaddr(node)[0]

Both routine will get the hostname from
/etc/hosts

For validations, cmapi read hostname from columnstore.xml and compare it with
socket.gethostname()

socket.gethostname() returns the host shortname of the current computer.

If in /etc/hosts is only the long names was saved, the comparisation fails,
because the string of the host long name and the host short name are not identical.