We are using Ignition on Linux (CentOS 7) gateways in production with a Samba 4 AD domain (redundant DCs). We use the domain for authentication and roles management. It works just fine.
For setting up with LDAPS we had to import the AD domain root certificate into the Java trusted certs store, otherwise Ignition complained that it couldn’t verify the DC’s server certificates. On our CentOS 7 gateway servers it was sufficient to place the exported domain root cert into /etc/pki/ca-trust/source/anchors and run the update-ca-trust command (see man update-ca-trust).
Steffen