Hello, and thank you for using Cisco Support Forums. From what i understood, the first time you set up ACI the APIC discovered the switches. Then the APIC was erased and the APIC cannot discover the switches. This is because the switches still have a configuration on them from the first time they were registered to the APIC and ACI Fabric.
On the switches, the appropriate command to erase the configuration is setup-clean-config.sh <image.bin>. It is suggested you first look at boot flash and copy the ACI image name to then insert as an argument into that command. Also, I suggest you setup boot variables first with the setup-bootvars.sh <image.bin> command. In summary:
- setup bootvariables with: setup-bootvars.sh <aci-n9000.bin>
- erase config with: setup-clean-config.sh <aci-n9000.bin>
When the switches reload they should return to the (none)# prompt, at which point the APIC should discover its directly connected leaf and the discovery and registration process can proceed from there. I hope this helps, have a nice day
