Oracle OpenStack for Oracle Linux uses groups to define the role a node has in an OpenStack deployment and the OpenStack services it runs. The default groups are compute, control, database, network, and storage. A node can belong to more than one group and can run multiple OpenStack services.
The minimum supported deployment of OpenStack contains at least three nodes:
Two controller nodes, each node belongs to the control, database, network and storage groups.
One or more nodes belonging to the compute group.
Single-node deployments (sometimes referred to as all-in-one deployments) are not supported.
As your scaling and performance requirements change, you can increase the number of nodes and move groups on to separate nodes to spread the workload. However, you should note the following "rules" for deployment:
The nodes in the compute group must not be assigned to the control group.
The control group must contain at least two nodes.
The number of nodes in the database group must always be a multiple of two.
Each group must contain at least two nodes to enable high availability.