May I know what are the procedures to set one database on active, another on standby?

What I wish to accomplish:

Both server 1 & 2 have Network Load Balancer installed, and a common NLB IP address.Node1 & 2 are also linked with a seperate subnet that allows Node1 &2 to communicate each other for synchronization. Node 2 will synchronize database data from Node1. If Node 1 is down, it will failover to Node2 Database, and Node 2 will be the active database and Node 1 will synchronize with Node 2.

If Node 1 is suddenly up, then Node 1 will be the active database, and Node 2 will synchronize back with Node 1 again.

Does it auto-synchronize or do I need to run scripts in order for synchronization?