According to this link. If you add the same hostname cisco-capwap-controller.domain.com the AP will resolve all of them and continue with normal join proces like it does with multiple controllers with DHCP option 43. So the comment below is slightly inaccurate according to this. I am doing a test right now I will post the results.
a quote from the link that Scott sent:
When an AP receives an IP address and DNS information from a DHCP server, it contacts the DNS to resolve CISCO-LWAPP-CONTROLLER.localdomain. When the DNS sends a list of controller IP addresses, the AP sends discovery requests to the controllers.
The AP will attempt to resolve the DNS name CISCO-LWAPP-CONTROLLER.localdomain. When the AP is able to resolve this name to one or more IP addresses, the AP sends a unicast LWAPP Discovery Message to the resolved IP address(es). Each WLC that receives the LWAPP Discovery Request Message replies with a unicast LWAPP Discovery Response to the AP.
I just finished my test. I had one DHCP pool with a seperate dns sufix and forward lookup zone on Microsoft DNS.
I created 2 hosts cisco-capwap-controler with different IP addresses. A host reccord.
I pointed 4 capwaps to this DNS. And they load ballanced 2 on each controller. So for me it is proved that the capwap gets knowledge of both controllers and continues normal join process where it joines the least loaded WLC.
It doesn´t show on the AP console what Controller it resloves. Just says (OK) I wonder how that can be seen. Perhaps some debugs on the WLC´s at the same time or to a packet capture on the CAPwap switchport. But I am happy for now.
Do your sites utilize different DNS suffixes? When the AP looks for CISCO-CAPWAP-CONTROLLER it will append whatever DNS suffix was assigned to it during DHCP assignment. So for the main site you could have DHCP return division1.domain which then gets translated as CISCO-CAPWAP-CONTROLLER.division1.domain. The next site would return division2.domain, etc.
Is there a reason why you are using DNS over DHCP? Merely curious, most all sites I've ever worked with have gone the DHCP route, only time looking at DNS was when they were using Infoblox and had issues getting the DHCP options going.
Transferring Crash file from standby: Login to the Active WLC in HA.
From CLI: (Cisco Controller) >transfer upload datatype crash (Cisco
Controller) >transfer upload filename (Cisco
Controller) >transfer upload mode tftp (Cisco Controller) >transfer
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