I’m running Graylog and I have a primary domain controller and a failover, I was applying some upgrades to my primary domain controller, finished up and bought it back online, but Graylog would not let me log in to it, I had to log in as the local user so I think that might be a bug (I was able to access the DC from other services).
Also, would it be possible to have the ability to add a second AD server for authentication please?
As a general rule, I never specify the name of an actual domain controller for these types of applications. Instead I add a CNAME in DNS and list a couple of domain controllers. If one of the domain controllers has a problem, it’s easy to remove the CNAME pointing to it.
A quick and dirty alternative is to specify the root domain name of your forest or domain.