There are 2 types of DB systems on virtual machines:
A 1-node VM DB system consists of one VM.
A 2-node VM DB system consists of two VMs clustered with RAC enabled.
Reference:
https://docs.cloud.oracle.com/en-us/iaas/Content/Database/Concepts/overview.htm Oracle Cloud Infrastructure offers single-node DB systems on either bare metal or virtual machines, and 2-node RAC DB systems on virtual machines. If you need to provision a DB system for development or testing purposes, then a special fast provisioning single-node virtual machine system is available.
You can manage these systems by using the Console, the API, the Oracle Cloud Infrastructure CLI, the Database CLI (DBCLI), Enterprise Manager, Enterprise Manager Express, or SQL Developer.