I have resolved half of the problem by specifying the DNS servers using the neutron subnet-update command to override the default DNS servers but I an unable to figure out how to set the search parameter and domain.

Example:

search openstacklocal
nameserver 10.128.0.25
nameserver 10.128.0.26

How do I make it look like:

domain mydomain.com
nameserver 10.128.0.25
nameserver 10.128.0.26
search subdomain.mydomain.com subdomain.mydomain.com

Changing on the network node, update in the "dhcp_agent.ini" file

dhcp_domain = mydomain.com

Results in

search mydomain.com
nameserver 10.128.0.25
nameserver 10.128.0.26

I'm still missing the domain parameter as well as multiple search domains