I'm setting up new SDN Managers and trying to understand how the failover works but the instructions provided from IR and Microsoft do not explain how the listener knows to failover. How is this setup? Is there an option is the listener install for this? Are there commands to apply to the Manager to flag one as Primary and Secondary?
Instructions from Micorsoft:
Deploying Skype for Business SDN Interface with primary and secondary failover
To overcome server failures in a single SDN Manager deployment, the SDN Interface can take a second SDN Manager as a failover alternate for all the connected Dialog Listeners. When a disconnected Dialog Listener attempts to deliver messages to the primary SDN Manager, a failover protection algorithm will switch to the alternative SDN Manager to ensure that the SDN Interface provides continuous service when server failures occur. In this case, the alternate SDN Manager becomes the new primary service provider. Call states are lost during the failover transition, because state is kept in memory on the primary SDN Manager. This may cause inconsistent or incomplete message reporting delivered to
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subscribers until the new active SDN Manager can establish a consistent view of the ongoing media streams.
Note
In the event of fail over, the secondary computer is promoted to the new primary node. Restoring the second node will automatically make it the secondary node, and the new primary node will stay in place until it fails over.
