So, is reinstalling an option? I suggest to reinstall and complete the installation procedure from the cluster-admin UI as described in Installation — NS8 documentation.
The documentation is a work in progress. We strive to keep it up to date with new features and enhancements. Please read it carefully because some things has changed since Beta 1. If something is not clear, feel free to ask.
# The following lines are desirable for IPv4 capable hosts
# 127.0.1.1 is often used for the FQDN of the machine
127.0.1.1 thishost.example.org thishost <<<=================
192.168.1.10 foo.example.org foo
192.168.1.13 bar.example.org bar
220.127.116.11 master.debian.org master
root@ns8:~# cat /etc/hosts
# commented by set-fqdn #127.0.1.1 ns8.debian.toto-dev.org ns8 <<<=====
# The following lines are desirable for IPv6 capable hosts
::1 localhost ip6-localhost ip6-loopback
127.0.1.1 ns8.debian.toto-dev.org ns8 <<<=============================
When I entered the FQDN in the UI, it changed my entry in /etc/hosts to the right one.