Controller redundancy

[Lawrence Desmarais]

Hi @All 

I've got controller with dual port, who acts like an unmanaged switch, they are visible if they are in access mode. they want to connect each port of my controller to two different switches c9300-24t on the same vlan. I have to use RSTP. 
All I've got so far is flapping or flooding. 
Is it possible?
What kind of configuration do i need to make it work?

I've tried a lot of configuration 
regards, 

[MHM Cisco World]

run bdpuguard in Port of Both SW 
if the Controller by chance forward the BPDU then the port will go to err-disable and then you will know that you can not connect it to both SW 
if NO and you only see mac flapping then it OK (not optimal but it oK)

MHM

[Lawrence Desmarais]

When my ports are flapping, I lose the connection with my controller. Which is not ok.

[MHM Cisco World]

what is SW you have Nexus ?

MHM 

[Lawrence Desmarais]

My VLAN is composed of Catalyst C9300-24t and C9300-48t.

[MHM Cisco World]

The PO from controller to both SW impossible.

The SW need to be stack to config PO.

Can you ask controller team if then can config one link primary and other as backup.

Thanks 

MHM

[Lawrence Desmarais]

is it possible to use Eterchannel for the same application? The conception team want to connect many controller who mesh it out into many switches.