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.
The terms are being confused sadly which is causing an issue. There's WCFS (Windows Clustering Foundation Services) which FCI (Failover Cluster Instance) runs on and requires shared disks. An AlwaysOn AG can also run on WCFS but it uses non shared storage and provides live read only replicas.
In other words A FCI is a shared storage architecture and you fail over from node to node. FCI doesn't in any way provide a 'read only' solution out of the box. Usually you will do mirroring+snapshot/log shipping or something else if you only have FCI. Right now what you are doing is simply adding another failover node, not an AlwaysOn AG.
This is what you are looking for (from the link). Note the multi node cluster with shared storage and the non shared storage AG:
Right now this is what you're doing. You're simply adding a 3rd node to the shared storage cluster:
This guide works well if you already have a FCI and want to add AG to it. Just look for how to install an AG. I would go through the steps for you but there's a lot of steps and you're better off going with an actual guide with screenshots and such. Do you have somewhere to test this in? Have you tried an Azure instance to test with if not? I would not recommend doing this live to prod. Here is some good documentation from Microsoft. Are you also sure that your code is AG compliant?
If you use MSDTC or cross db transactions you could create a serious problem.
Now the bigger question is are you the person who will be supporting this and is this prod? It seems like it's important because you're utilizing both FCI and AGs. I would highly suggest you research FCI and AGs in depth before deploying to prod. There are tons of resources out there. I would highly recommend not attempting to push this through on prod with the current understanding. You might set yourself up for major failure and your HA solution can bring you down.
Best Answer
The RSAT tool was updated with the general availability of Windows Server 2016. By going to the same link as the preview RSAT, https://www.microsoft.com/en-us/download/details.aspx?id=45520, you can update your workstation with the new version.