PVE Cluster question

Hello,

I'd just like to know if a pve cluster pools physical hardware resources such that VMs pull from that central pool, and not from any particular server?

For example, in a cluster with 2 nodes, each with 10GB of RAM, is it possible to create a VM with 15GB of RAM?

I've read the wiki article on the PVE cluster and couldn't quite figure this out.

Thanks.