They are single node from a HA pair stand point, but you can build a cluster of multiple nodes.
During setup on the first node you should see this prompt:
Do you intend for this node to be used as a single node cluster? {yes, no} [no]:
If you pick No, then you will also see this message:
Private cluster network ports [e0a,e0b].
Cluster port MTU values will be set to 1500.
Cluster interface IP addresses will be automatically generated.
Do you want to use these defaults? {yes, no} [yes]:
Typically you will want to pick yes. This will auto create cluster lifs and auto assign them IPs in the 169.254.x.x range.
You can join more nodes later easily, since the cluster networking is ready to go. Just no HA, no storage failover, etc since the disks are isolated to their home node only.
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