9800 WLCs in HA

Hi everyone!

I configured 2 9800 WLCs in HA that were supposed to be on the same racku nit but unfortunately people on site change the location of WLC-2 to a "redundancy" site on the same location. Now the 2 WLCs are on the same LAN but not on the same rack unit, as they were connected each other in the redundancy port.

Now as it's not an option to to have HA by SSO, what can be a solution to redundancy?

I thought since APs can have a primary a secondary controller, maybe leave both controllers with the same config with different IP addresses, in that way APs should look for WLC-2 when WLC gets down, right? Is this SSO? What configuration I should have in the second WLC?

Both controllers are on same LAN but far from each other. Thanks for the help!