Sql-server – SQL 2017 Standard Availability Group

Does the Windows Failover Cluster for a multi-subnet SQL Server Availability Group require a static IP entry for each subnet?

The CNO will require an IP address for every subnet it could reside in.

I am running SQL Server 2012 on Windows Server 2012 Hyper V VMs in 2 separate subnets in the same domain. I understand that I will need an IP from each subnet when I create the listener for my AAG. What I am unclear on is the configuration of IPs on the underlying Windows Failover Cluster.

For the underlying WSFC you'll need at a minimum:

Node1 - IP Address for each unique subnet for each network interface

Node2 - IP Address for each unique subnet for each network interface

CNO - IP Address for each unique subnet

EX: 2 nodes, 2 subnets, 1 interface per node, subnets 192.168.1.1/24 and 192.168.2.1/24

Node1: 192.168.1.10

Node2: 192.168.2.10

CNO: 192.168.1.20, 192.168.2.20

Also, if the server hosting the secondary replica does require its own IP, does it also require its own unique cluster name (and can you explain why this is necessary)?

I'm not sure I understand this part of the question. All of the resources can only belong to a single cluster - there is no cluster inside of a cluster thing.

Edit - I looked at the link that you posted and I'm not sure why the author stated "•Cluster name for each node". My only guess is they meant each node needs a name and IP (for the node). Otherwise it's not a correct statement, the author should probably be contacted.

I think this is normal behavior as only one cluster IP will be up at one time. When trying to force the secondary or third IP up you should get the error message you stated.