Let me tell you a story about how people deploy, instead:
Most people put in a dns entry of "aruba-master", because when access points are new, they will get a dhcp address, and dhcp suffix. They will send "aruba-master.<dhcp suffix>" to the DNS server that the AP receives and try to resolve that to find the controller. It is a very easy way for APs to find the controller, no matter where they are located.
When APs contact the controller, it sends its AP-name and AP-group to the controller. In the AP-group configuration on the controller there is a profile called the "AP system profile" which can have an LMS as well as a Backup LMS ip. So when an AP contacts a controller using any method and sends its information, the controller will send back an LMS-IP and Backup LMS-ip if configured. If there is NO lms-ip or backup lms-ip configured, the AP will just stay on the first controller it finds. If there is an LMS-ip, the AP will be redirected to that controller after finding the initial controller. If there is also a backup lms-ip configured, the AP will fail over to the backup lms-ip, if contact is lost with the lms-ip controller.
When WLANs get larger, you get more controllers and you do not want APs to go to another country to find their local controller; you want them to find the local controller first. In that case, you put the DHCP option 43 and 60 into the DHCP scope that provides an ip address to the AP, so that you can make exceptions to the dns discovery for each local subnet. The DHCP options will override the DNS.
Last but not least, the local broadcast will override both, but it is pretty much only used when you have a single controller and your APs are in a single subnet that the controller already has an ip address in.
To make a long story short, most people start out with DNS. They then apply DHCP options if they need APs to find a local controller first.
You can also provsion APs, either using a console cable, or in the Configuration> Wireless> AP installation screen to hardcode their local controller so that there is no discovery process. Even when you hardocde the ip address for the APs master in this fashion, the AP can still be redirected if there is an entry in the AP system profile for LMS-IP or Backup LMS-ip.
If you are having problems please also see the discovery troubleshooting video in the knowledgebase here (login required): http://community.arubanetworks.com/t5/Community-Knowledge-Base/Aruba-Controller-and-AP-Troubleshooting-Part-1/ta-p/18988