Hi, In a four node ISE setup (two PSN, and two MnT), which of them do I connect to from DNAC for integration? Do I need to enable pxGrid on all nodes? What cert requirements are necessary on the ISE side?
I assume the PAN roles are also on your MnT nodes? If so then pxgrid is probably best enabled on the PSN nodes. Bear in mind that normally pxgrid would be dedicated PSNs (that are not also performing dot1x/tacacs authentication).....it would depend on the current load of your PSN.
Here is a reference guide for ISE and DNAC integration.
As per Cisco documentation, you should integrate DNAC with ISE PAN primary node in a distributed deployment.
as already meantioned for the beginning it is enough to add the Primary PAN. Make sure Port TCP/443 is opened between DNAC and ISE for PxGrid.
ISE and DNAC will automatically exchange certificates.
If primary PAN is successfully added you can see all 4 ISE Nodes in the Design section.
If you furthermore want external Authentification for DNAC Web-Login, soyou can login i.e. with your Domain User Account, you also want to add your PSNs under "Authentication and Policy Servers".
Here is a great Guide for TACACs+ (but will also work for RADIUS, if you ignore the TACACs+ specific options).