DDNS is a project that lets you host a Dynamic DNS Service, similar to DynDNS/NO-IP, on your own servers.
You have to own a domain where your Registrar allows you to add NS-Records for Subdomains, as this is handled by DDNS.
You should have a server running continously. Go, Redis and PowerDNS have to be supported by the running OS.
Redis is used as the data store with features like automatic expiration of hosts ...
PowerDNS is the DNS server software used by DDNS to handle the DNS requests for your subdomain. DDNS provides a suitable backend software for PowerDNS.