Exchange 2013 DAG CreateCluster() Failed Error

So far I have encountered the following problem in two completely separate Exchange 2013 Preview environments when creating a Database Availability Group [DAG].

Started by creating a simple DAG without any problems, only specifying its IP address and letting Exchange decide which server to use as the Witness Server. However, whenever I tried to add any of the mailbox servers to this DAG, I would get the following error:

 

Note the "CreateCluster() failed with 0x5. Error: Access is denied" part of the error message.

If we look at the dagtask log mentioned in the error above, we will see all the tasks Exchange performs when adding a server to the DAG and where it failed:

[2012-10-26T18:23:18] ClusterSetupProgressCallback( eSetupPhase = ClusterSetupPhaseConfigureClusterAccount, ePhaseType = ClusterSetupPhaseStart, ePhaseSeverity = ClusterSetupPhaseInformational, dwPercentComplete = 94, szObjectName = DAG1 in organizational unit CN=Computers,DC=letsexchange,DC=com, dwStatus = 0x0 )

[2012-10-26T18:23:18] ClusterSetupProgressCallback( eSetupPhase = ClusterSetupPhaseConfigureClusterAccount, ePhaseType = ClusterSetupPhaseEnd, ePhaseSeverity = ClusterSetupPhaseFatal, dwPercentComplete = 94, szObjectName = DAG1 in organizational unit CN=Computers,DC=letsexchange,DC=com, dwStatus = 0x5 )

When dwStatus is 0x0, it means “success” but 0x5 means “access denied” just like the error we received in the Shell.

After some troubleshooting, I found out that the DAG’s Cluster Name Object [CNO] wasn’t created properly! There were two problems with the CNO:

1. The Exchange Trusted Subsystem universal security group didn’t have Full Access permissions to it;

2. The CNO was enabled in Active Directory:

After assigning full control to DAG1 AD object to the Exchange Trusted Subsystem and then disabling it, everything worked just fine:

 
For more information: Pre-stage the Cluster Network Object for a Database Availability Group

Hope this helps!