- You need to make a VIP beween the two MDs and then add the two other two MDs to the VRRP.
- Your discovery method, DNS, dhcp option 43 should point to that VIP.
- When APs discover a cluster, the list of nodes are pushed to the APs flash and upon reboot the APs no longer, discover using DNS, or DHCP or multicast: they attempt to connect to the list of nodes in their flash.
- There is no need to put an LMS-IP into the ap-group, because the AP is assigned a controller by the cluster leader when it connects to one of the nodes in the nodelist.
- LMS-ip is only necessary if you have more than one cluster and there is a chance that your APs will initially discover the wrong cluster and will need to be redirected to the correct one, OR you need to enter a backup-lms for redundancy to a second cluster (overkill).
If you have 2000 APs to migrate, I suggest you contract a VAR or work with your Aruba SE to get information on how to proceed, because there are many ways to configure things suboptimally.