Why does the small business need cloud?

1. Saving cost for IT infrastructure
2. Quick installation and deployment
3. High performance expedition
4. Fault tolerance and disaster recovery ability
5. Fast internet access ability

OpenStack Basic Concept – 2

There are some important concepts about infrastructure layout in OpenStack.

Regions:  invented by AWS. Region is based on the geography location. It is more like a physical datacentre. Regions are isolated between each other. But regions can share the keystone and dashboard. Users can choose a close region to deploy their application. Region is also considered in DR plan.

Availability Zone(AZ): AZ is the division in a Region. Usually when the hardware is deployed,  separated infrastructure such as power supply, air-conditioning or network connections. It provides some kind of redundancy capacity. AZ is visable to the user and end user need to select an AZ when they create an instance.

Cell: cell is used in OpenStack for scaling and expanding.  In large scale of OpenStack deployment, DB and AMQP will be the bottleneck, in that case, cell can be introduced, each cell can own the DB and AMQP.

Host Aggregate:  a bounch of computing nodes and usually these nodes have same character such as SSD disk, same OS. Host Aggregation is used by OpenStack internally (manually by scheduler). Host Aggregate usually won’t be visible to End users

OpenStack Component Introduction

OpenStack sub projects and components

OpenStack is actually bunch of sub projects including:

·      

Nova:  Nova is the OpenStack main project related with computing resource management, itself contains component such as Nova-API, Nova-filter, Nova-computer, Nova-volume etc.

Keystone: Keystone is an OpenStack project that provides Identity, Token, Catalog and Policy services for use specifically by projects in the OpenStack family.

Horizon: The OpenStack Dashboard (Horizon) provides a baseline user interface for managing OpenStack services." Dashborad is a Django APP.

Glance: The Glance project provides services for discovering, registering, and retrieving virtual machine images.

Quantum/Neutron: are the OpenStack network related projects and the most difficult component at the moment.

Swift: Swift is a multi-tenant, highly scalable and durable object storage system that was designed to store large amounts of unstructured data at low cost via a RESTful HTTP API.

OpenStack Basic Concepts - I

This Blog introduces some of very basic concept in OpenStack.

Tenant:  Tenant was previously called Project in Nova.  It is the unit when user requires the resource from OpenStack. Or in another word, it is more resource related. For tenant, we can specify the ‘quota’ such as the Number of volumes,size of all volumes,Number of instances each tenant can own.

User:  a user is an ID with dedicate username, password, email info etc. it is the authentication object for a service in openstack.

A user must belong to a tenant or multiple tenants. If no tenant is assigned, OpenStack will use a tenant with the same ID as the user.

Role:  role is the combination of privileges. It is not compulsorily required in OpenStack but very useful in management. Administrator can create role and assign it to user.

Service: A service provides one or more endpoints through which users can access resources and perform operations. The service is provided via REST API. Service can be thought as ‘type’ of endpoint.

End Point: A network-accessible address, usually described by a URL, where a service may be accessed. It is the specific service can be used by OpenStack User.