Turnspit, in general it would be possible with a Linux High Availability setup where one system is in a hot-standby mode and takes over the main IP when the other node fails. However, you would have to keep the settings of the two Omada Controllers in sync.

What's also possible is a manual take-over of the EAPs by a second Omada Controller running on another server if both servers are in the same subnet as the EAPs. But with this soultion there will be a downtime until the EAPs have been manually adopted in the second controller.

AFAIK, Omada Controller itself has no automatic fail-over function at this time.