ESXi can be integrated with Active Directory. Active Directory provides authentication for all local services and for remote access through the vSphere Web Services SDK, vSphere Web Client, PowerCLI, and vSphere CLI.
You can configure Active Directory settings with the vSphere Web Client, as discussed in the vCenter Server and Host Management documentation, or use vicfg-autconfig.
vicfg-authconfig allows you to remotely configure Active Directory settings on ESXi hosts. You can list supported and active authentication mechanisms, list the current domain, and join or part from an Active Directory domain.