The following servers in the Windows Failover Cluster are not in Active Directory: <server name>. This is usually the result of an incomplete membership change (add or remove) of the database availability group.
I ran into this error recently while trying to remove two Exchange 2010 members from a database availability group (DAG).
The error stated that a member of the DAG, a server named EXC3, did not exist in Active Directory. This was odd because queries to the Exchange 2010 management tools only returned two Exchange servers–EXC1 and EXC2.
We further confirmed that there was no computer account for EXC3 in Active Directory Users and Computers. We did however, see remanents of EXC3 in ADSI Edit.
Talking with our customer we discovered that there had been a third Exchange server, named EXC3, that had crashed and was never recovered.
Fix–The following servers in the Windows Failover Cluster are not in Active Directory
To verify the status of all nodes in your database availability group, open PowerShell and import the Windows Failover Clustering cmdlets with Import-Module.
C:\> Import-Module FailoverClusters
Next, run the Get-ClusterNode cmdlet. This will retrieve the status of all our nodes.
In the example above, we can see EXC1 and EXC2 are operational, whereas EXC3 is offline.
Because EXC3 no longer exists (and the fact we plan to collapse the entire DAG anyway) we can forcibly evict the failed node. To do this issue the following command.
C:\> Get-ClusterNode -Name "EXC3" | Remove-ClusterNode
Are you sure you want to evict node EXC3
[Y] Yes [N] No [S] Suspend [?] Help (default is "Y"): Y
You will be prompted to confirm. Press enter to accept the default action of “Yes”.
If we repeat the first Get-ClusterNode command we will only have the two operation cluster nodes remaining.
With no more failed nodes we can remove the two operational nodes using either the Exchange 2010 management console or PowerShell.
Have you run into this error while add or removing members to a DAG? What did you do to fix it? Drop a comment below or join the conversation on Twitter