Ubuntu + AD; Failed to join domain: failed to set machine spn: Constraint violation
I know this post is old but I just ran into the same problem and here is what I found. If you are trying to add a computer to the domain but you are not using a "domain admin" account. The delegated account rights need to include at least the following:
-This object and all descendants
•Create Computer objects
•Delete Computer objects
-Descendant Computer objects
•Read all properties
•Write all properties
•Validated write to DNS host name
•Validated write to service principal
Hope that helps!
I also ran in to the same issue winbindd simply would not start. The entry was already in /etc/hosts but I needed to change /etc/nsswitch.conf and changed to order so that 'files' came first.
hosts: mdns4_minimal files nis dns mdns4 myhostname
hosts: files mdns4_minimal nis dns mdns4 myhostname