OpenStack is a lot of open-source software instruments for building and managing distributed computing platforms. A great many people and organizations like Red Hat, Dell, and Rackspace have made OpenStack. They cooperate with the objective of making OpenStack the most robust and secure platform available. OpenStack competes with cloud stages, for example, Amazon Web Services and Microsoft Azure. Organizations us it to oversee both open and private veils of mist. OpenStack is an IaaS (framework as a help). The foundation makes it simple for designers to assemble administrations and applications on it. The OpenStack project was initially started by RackSpace in a joint effort with NASA in July 2010 where it increased a ton of consideration in a short period of time. NASA contributed their code from the Nebula cloud task to OpenStack compute, and RackSpace contributed the majority of code behind their cloud stage, explicitly Cloud File items. Technology giants like Intel and Dell grasped OpenStack following it began and now there are more than 140 organizations that help the OpenStack activity. Giants like IBM, AT&T, and HP all as of late declared they've joined OpenStack and Sony has moved a bit of its PlayStation administrations from AWS to OpenStack in Rackspace in the wake of experiencing a digital assault a year ago which made a significant blackout their administrations.

OpenStack Architecture

OpenStack has a client-server architecture that provides a REST API to the user through which requests to the server can be performed. All the file (Image data) operations are performed using a glance_store library, which is responsible for interaction with external storage back ends and (or) local filesystem(s). The glance_store library provides a uniform interface to access the backend stores.

Glance uses a central database (Glance DB) that is shared amongst all the components in the system and is SQL-based by default. Other types of database backends are somewhat supported and used by operators but are not extensively tested upstream.

Following components are present in the Glance architecture:

• A client - any application that makes use of a Glance server.
• REST API - Glance functionalities are exposed via REST.
• Database Abstraction Layer (DAL) - an application programming interface (API) that unifies the communication between Glance and databases.
• Glance Domain Controller - middleware that implements the main, Glance functionalities such as authorization, notifications, policies, database connections.

• Glance Store - used to organize interactions between Glance and various data stores.

• Registry Layer - optional layer that is used to organize secure communication between the domain and the DAL by using a separate service.

OpenStack Component

• Nova is the primary compute engine of OpenStack. Developers designed it to manage virtual machines on standard hardware. Nova is similar in function to EC2 from AWS and was one of the contributions from NASA when OpenStack got started. 

• Swift is the object storage system contributed by Rackspace. Swift is similar to S3 from Amazon in that it’s able to scale to massive sizes. Using a unique identifier, developers utilize Swift to decide where objects are stored. This allows the system to easily scale because developers don’t have to worry about the storage capacity on a single system. 

• Cinder is the block storage component of OpenStack. It works more like traditional storage in performance and architecture. 

• Keystone is the main tool for user authentication and role-based access controls. It acts as a central directory of all users and their respective permissions. Keystone supports traditional username and password logins as well. 

• Glance allows the user to spin up virtual machines by creating templates for them. It works with Cinder to store images it creates from templates, but it can also create its own images. 

• Horizon is the only graphical component of OpenStack. It’s basically a web-based tool that users and administrators use to access the other components. Many call it the dashboard of OpenStack. 

• Neutron manages all network associated with OpenStack clouds. It includes APIs that allow administrators to customize and deploy a variety of network types such as flat networks, VLANs, or VPNs. 

• Heat helps developers manage the infrastructure needed for a cloud service to run. It defines all the resources each application needs to run properly. 

• Ceilometer is the billing engine of OpenStack. It’s still evolving, but consider it the metering agent of OpenStack.