This was an interesting little one that happened in my Azure Service while using Azure Connect to join my Role instances to my on-premise domain controller. Let me lay out the scenario..
Trying to apply some best practice to my environment I an using a regular domain user account in my Role configuration for Azure Connect (why would you ever embed a domain administrator account in a static configuration file ?!?!).
DomJoiner is simply a regular user, users can join machines to a domain.
Everything was working along perfectly fine until yesterday. I applied the Roles to my Virtual Network group in the Azure Portal and nothing happened. My machines did not reboot (domain join), they did not appear in the domain, nothing.
Finally I ran across a specific Azure Connect log file “integrator.log” found at %programfiles%\Windows Azure Connect\Endpoint\Logs
Within this log I could see the configuration being received, Azure Connect linking up and my error:
RRAS interface connected
DNS server configured on RRAS interface
NetJoinDomain failed with error code 8557. Target domain......
Oh, an error code, lets go trolling. Search was letting me down. All the error references were for Server 2000 Active Directory and I am using Server 2008 R2. Also, no references to the error and Azure. I can’t image I am the only one that has seen this.
I opened ADSIEDIT.msc, selected the properties of the correct naming context, then cleared the setting ms-DS-MachineAccountQuota.
This all happened because I am using the prudent practice of using a regular user account ( not a domain administrator) to join my Azure Role instances to my domain with Connect. But then most developers I know would only be using a Domain Administrator account and may never see this issue.