Slave does not automatically authenticate when master is down

Question

We are running MFA in a dual server master-slave configuration. When the master MFA server is down the slave does not automatically take over. You have to open the GUI and promote the slave server to master to get it working again. I expected the slave to
authenticate without administrator intervention. Is this by design? We are running latest version 6.3.1.1. 
In this thread
https://social.msdn.microsoft.com/Forums/sqlserver/en-US/86efa99d-361c-4f83-bfba-fd75b4505590/azure-mfa-server-replication-and-failover?forum=windowsazureactiveauthentication
someone mentions the same problem. The reply goes as follows:
"Regardless of the UI, if an authentication request is sent to the slave, it will process it"
If the master server is offline, it does not.
it is also mentioned that
"One option for HA is to point at one MFA Server as a primary authentication target and another as
a backup authentication target"
Where? I cannot find this option anywhere in the MFA interface. Thanks in advance.

Answer 1

Hi Sadiqh,
thanks for your reply! I had already dug through the link you gave me. For your information: we are using MFA to secure a sharepoint site via IIS. I understand about the 'no updates without the master' thing but in the link it is also said:
"A slave can process authentication whether the master is up or not"
It can, but you have to promote it to master manually. It does not process authentication requests from remote users on its own.
"The slave will only do work when the master is offline"
What work? It appears to not include authentication request from remote users. At least, not automatically. You have to promote it to master first.
Finally, it is being said:
"The on-premises Azure MFA Servers don’t do any kind of failover on its own"
So, if I am understanding this right you WILL HAVE to promote the slave server to master manually when the master is offline. I am wondering if I can use the MFA API to write a custom script which checks if the master server is offline or not and promote
to master if needed. If so, I would expect this functionality to be already there with MFA itself. What's the purpose of an MFA cluster if it requires manual user intervention for failover?
Edit: I am now looking into the powershell module obtainable at http://azure.microsoft.com/en-us/downloads/ but
none of the commandlets seem to support managing the multi factor auth providers via powershell.
Also, the Azure AD module obtainable at https://msdn.microsoft.com/en-us/library/azure/jj151815.aspx seems to be focused at user administration and no support
for Multi-Factor Auth providers.
Also, the command line tool obtainable athttp://azure.microsoft.com/en-us/documentation/articles/xplat-cli/ also does not seem to have support for managing multi factor auth providers.
Any ideas/suggestions?