Openstack is a set of components that when put together provide the functionality of a private Cloud.
Openstack is composed of several services that can be deployed independently and together provide a set of functionalities. Those services are mostly written in Python and communicate either via HTTP APIs or RabbitMQ queues. Persistence of data is achieved using a MySQL database. High availability is usually achieved by using Pacemaker to manage services.
Due to its maximalist approach, Openstack has a lot of components to provide a wide range of services. The main components are the following:
- Keystone: an identity service, provides authentication and authorization, enabling multi-tenancy in Openstack clouds.
- Glance: the image service responsible for managing cloud images for VMs.
- Nova: the compute engine of Openstack, responsible for creating, scheduling and overall managing of VMs.
- Neutron: an network service that allows for defining networks to provide connectivity between workloads withing the Openstack cloud.
- Cinder: the block storage service, responsible for provisioning and managing persistent block devices.
- Swift: a S3 compatible Object Storage service.
It’s worth noting that these services are usually higher level abstractions around lower level components such as OVN, libvirt and storage providers such as Ceph and Linstor.
The project has been around for more than a decade, but development is very slow and it does not have a very good perspective for the future.