system_domain-name.xml.in

<?xml version="1.0"?>
<interfaceDefinition>
  <node name="system">
    <children>
      <leafNode name="domain-name" owner="${vyos_conf_scripts_dir}/system_host-name.py">
        <properties>
          <help>System domain name</help>
          <constraint>
            <validator name="fqdn"/>
          </constraint>
        </properties>
      </leafNode>
    </children>
  </node>
</interfaceDefinition>