The one thing I'd want to know first is, why do I need High Availability and what does High Availability mean (e.g. what's the SLA)? Based on those requirements you can come up with the right architecture for Tableau Server.
I read all the documentation on Tableau Server for Scalability and High Availability.
When Configuring the Tableau server for scalability, I configure the Worker Nodes 1 and Workers Nodes 2 and made the active repository to be on Worker Node1 and Passive Repository to be on Worker Node 2.
Now I want to configure the backup primary and the question arises in my mind that do we need to mention the backup primary (Computer Name or IP address) along with Primary while installing the worker nodes.