Add ESXi host to AD using authentication services

To add VMWare ESXi host to AD using authentication services use:

Browse to the host in the vSphere Web Client inventory.
Click the Manage tab and click Settings.
Under System, select Authentication Services.
Click Join Domain.
Enter a domain.
Enter the user name and password of a directory service user who has permissions to join the host to the domain, and click OK.
Click OK to close the Directory Services Configuration dialog box.

Note that for authentication to succeed, a group named "ESX Admins" (we cannot change the group name) should be created in AD.

Refer:

Anonymous