Dynamic update of virtual hosting domains

[Stephane Bortzmeyer]

On Tue, Jan 29, 2008 at 11:37:40AM +0100,
 Peter Rabbitson <rabbit+list at rabbit.us> wrote 
 a message of 29 lines which said:

> www	cname @
...
> Sometimes I need to change <IP of web server> automatically, however enabling 
> dynamic updates on all (currently 9) virtual host domains seems ugly. I know I 
> can use the DNAME RR, but from my googling it seems that it is not favored in 
> todays infrastructure. Is there a way to organize things in such a manner, so 
> that the A record can point to a single place which can be then dynamically 
> updated?

Why not deciding that www.dynamic-domain.example.org is the canonical
name for your Web servers? In each zone, you put an alias:

www CNAME www.dynamic-domain.example.org. 

and you just update dynamic-domain.example.org.