- When booting an instance, its sanitized 'hostname' attribute is now used to
populate the 'dns_name' attribute of the Neutron ports the instance is
This functionality enables the Neutron internal DNS service to know the
ports by the instance's hostname. As a consequence, commands like
'hostname -f' will work as expected when executed in the instance.
When a port's network has a non-blank 'dns_domain' attribute, the port's
'dns_name' combined with the network's 'dns_domain' will be published by
Neutron in an external DNS as a service like Designate. As a consequence,
the instance's hostname is published in the external DNS as a service.
This functionality is added to Nova when the 'DNS Integration' extension
is enabled in Neutron.
The publication of 'dns_name' and 'dns_domain' combinations to an external
DNS as a service additionally requires the configuration of the appropriate
driver in Neutron.
When the 'Port Binding' extension is also enabled in Neutron, the
publication of a 'dns_name' and 'dns_domain' combination to the external
DNS as a service will require one additional update operation when Nova
allocates the port during the instance boot. This may have a noticeable
impact on the performance of the boot process.