Wireless Access

My customer network environment has 2 units of core switch running  HA in Active-Active mode. When 2 units of Aruba Controller connect to core switch, the Aruba controller should run HA in Active-Active or Active-Passive mode?

If in Active-Active mode it need 2 set of license, right? For example 2 set of AP and PEF license for both controller?

It is dependant on the type of controllers you are running, the design of the network and the requirements of your customer. My initial thoughts would be how does the routing work if you have an active/active core? If the controllers are capable of supporting Centralized Licensing then you will not need duplicate licenses.

http://www.arubanetworks.com/techdocs/ArubaOS_63_Web_Help/Content/ArubaFrameStyles/New_Licenses/Multi__Network.htm

Also need to be mindful of where APs will terminate. If it's 6.x deployment and all APs are in the same RF domain, then recommendation is to have APs terminate to one controller, with the other providing backup functionality.

If it's a 8.x deployment then consider clustering where both controllers can be used in an active-active configuration and provide redundancy as well.

Core switch will do the routing. That 2 units of core switch (HA) will run as virtual switch. 

For a start my customer environment only can support AOS 6.5 for Aruba 7205 controller because has AP105 on the network and have make sure it stable after migrate from Aruba 3400 (AOS 6.4). Then confirm is stable then upgrade again to AOS 8.x

When upgrade from AOS 6.5 to AOS 8.x does it still able to configure as Active-Active?

ArubaOS 8.0 is completely different.  The configuration is completely wiped when you upgrade, so you will have to redesign anyway.