OpenStack contains collections of services that work together to manage the virtual machine create, read, update, and delete (CRUD) operations. Each service can expose its resources to be consumed by external requests. For example, the nova service is responsible for spawning the virtual machine and acts as a hypervisor layer (though it's not a hypervisor itself, it can control other hypervisors, like KVM and vSphere). Another service is glance, responsible for hosting the instance images in either an ISO or qcow2 format. The neutron service is responsible for providing networking services to spawned instances and ensures that the instances located on different tenants (projects) are isolated from each other, while instances on the same tenants can reach each others through an overlays network (VxLAN or GRE).
In order to access the...