Sql-server – Active/active SQL Server Clustering in Installation Center (setup.exe)

You want to choose "Add node to a SQL Server failover cluster". When creating a Failover Cluster Instance (FCI), you will always do one initial cluster installation for the instance, then add nodes to that installation.

Keep in mind that Active/Active and Active/Passive as descriptors is very misleading. By it's very nature, each SQL Instance you install can only be active on a single node at any one time. To leverage multiple physical nodes at the same time, you will need to install multiple named FCIs to your cluster.

For example, let's assume a two node cluster. If we install a single named FCI to this, our layout would look like this:

NODE1:  CLSTSQL01\SQLServer01 (Active)
NODE2: 

This would be the result of you performing one "New SQL Server Failover Cluster installation" with the additional node additions for each node in your cluster. Now let's add a second instance to it so we can utilize each node. For this, we would install a second FCI to the cluster and end up with something like this:

NODE1:  CLSTSQL01\SQLServer01 (Active)
NODE2:  CLSTSQL02\SQLServer02 (Active)

Now, keep in mind that in a failover situation, on either node, the SQL instances could end up on the same node. For example, if NODE1 failed:

NODE1: <<DEAD>>
NODE2: CLSTSQL01\SQLServer01, CLSTSQL02\SQLServer02 (Active)

This is the basics of how you would arrange your instances. You will need to monitor your cluster if you want to make sure your instances are properly balanced across your nodes.