Chrissy LeMaire ran into a trust issue one one node of a cluster:
You know what’s scary as hell? When one node of an important cluster loses its trust relationship with the domain and you see the error “the trust relationship between this workstation and the primary domain failed”. That happened to me late last year with one of my SQL Server 2008 R2 nodes. The scary part was that I just didn’t know what to expect. The fix could be simple, or it could require a node rebuild.
Trust no one.