You want to use the Vhosts plugin:
in perlbal.conf
LOAD vhosts
LOAD Stats
CREATE POOL website_a_backends
SET nodefile = /etc/perlbal-website_A_webserver_ips.dat
CREATE SERVICE web_site_A_webservice
SET role = reverse_proxy
SET pool = website_a_backends
.....
ENABLE web_site_A_webservice
# This is what listens on your IP address and chooses the relevant
SERVICE for the domain
CREATE SERVICE public
SET listen = 0.0.0.0:80
SET role = selector
SET plugins = stats, vhosts
VHOST www.website-A.com = web_site_A_webservice
VHOST www.website-B.com = web_site_B_webservice
#.... list all your domains and the configs for them
VHOST * = default_webservice
ENABLE public
Hope that helps
Perlbal monitors your nodefiles, could you can have a script to update
those as required?
Leo