Explore OpenStack's Core Services: From Nova to Ceilometer

OpenStack Core Component Functions

Nova

Nova provides compute services, managing the lifecycle of instances (virtual machines or containers). It offers a RESTful API, abstracts underlying hypervisors (e.g., KVM, Xen), and supports horizontal scaling by adding hardware resources.

Neutron

Neutron delivers networking services, allowing creation of virtual network topologies, managing ports, and providing tenant‑isolated networks. Its plug‑in architecture supports various back‑ends (e.g., OpenVSwitch, Linux Bridge) and offers a REST API for integration.

Keystone

Keystone provides identity services, handling authentication, authorization, and management of users, tenants, and roles. It maintains a service catalog for all OpenStack services and supports multiple authentication mechanisms, with a default MySQL‑backed implementation.

Glance

Glance manages virtual machine image registration and retrieval. It supports role‑based access control, multiple image formats (RAW, QCOW2), and various storage back‑ends (Amazon S3, OpenStack Swift, local file systems). It also provides APIs for image upload and metadata handling.

Horizon

Horizon is the web‑based dashboard for OpenStack, enabling users to manage virtually all resources through a graphical interface.

Cinder

Cinder offers block storage services similar to Amazon EBS, providing on‑demand, scalable storage volumes. Originally part of Nova, it was split into its own project and supports multiple back‑ends, allowing volumes to be scheduled to different storage nodes.

Swift

Swift provides reliable object storage by replicating data across multiple nodes, ensuring durability and fault tolerance. It supports S3 compatibility and can scale by adding storage devices, offering a highly available storage solution.

Heat

Heat is the orchestration service that uses templates to define and deploy complex resource stacks (e.g., an Apache HA cluster). It follows a model similar to AWS CloudFormation, enabling automated provisioning of OpenStack resources.

Ceilometer

Ceilometer, introduced in the G release, provides telemetry services by collecting usage data from all OpenStack components across nodes, supporting billing, monitoring, and optimization.