Is one Bitcoin node has One wallet only?
As of v 0.14.x, Bitcoin Core supports only one wallet.  You can't create more than one.

You can sort of achieve this by having multiple wallet files and choosing which one you rename to wallet.dat.  You have to restart Bitcoin Core to change between them.  It's error-prone and not an officially supported feature.  You can read more about it at Bitcoin-qt multiple wallets and transferring between?