All new things are not out of nowhere, there is this life and past lives. Cloud computing is a product of IT technologies as they evolve. To understand cloud computing, we need to be aware of the development of the IT system architecture. See the next
Development of IT system architecture so far can be divided into three stages:
1, on a physical machine architecture this stage, deploy and run applications on a physical machine. For example, on a business to ERP system, if small, you can find three physical machines are deployed Web servers, application servers and database servers. If a larger scale, a variety of server cluster architecture can be used, but each cluster member still deployed directly on a physical machine. I've seen early customers are of this architecture, a set of application server, usually very low system resource usage, up to 20% are good.
2, virtualization architecture determines the physical server computing power is growing, the development of virtualization technology greatly improves the physical server resource utilization. This phase, to run several virtual machines on physical machines, applications deployed directly to a virtual machine. The benefits of virtualization is also reflected in reducing the number of physical machines to manage, while saving maintenance costs.
3, cloud computing infrastructure virtualization improved resource utilization single physical machine, with the application virtualization technology, IT environment, there are a growing number of virtual machines, then new demand arises: how IT environment virtual machine unified and efficient management. There is a demand supply, cloud computing boarded the stage of history.
Two, OpenStack Introduction
1. What is cloud computing: Cloud computing is a pay-per-usage model that supplies available, convenient, on-demand network access, can be configured into the shared pool of computing resources (including resources networks, servers, storage, applications, services)
2, several levels of cloud computing services included:
• SaaS (software aS a service): the online software as a service.
• Paas (Platform as a Service) : the platform as a service.
• Iaas (Infrastructure as a Service) : the hardware as a service.
3, OpenStack: by Rackspace and NASA to develop cloud computing platform, is an open source IaaS (infrastructure and services) cloud computing platform, so anyone can own to build and deliver cloud computing services, semi-annual, with written in Python
4, Opens tack history
5、OpenStack社区与链接
社区： www.openstack.org, wiki.openstack.org
邮件列表： http://wiki.openstack.org/MailingLists#General_List http://wiki.openstack.org/MailingLists#Development_List http://wiki.openstack.org/MailingLists#Operators
如何贡献代码： http://wiki.openstack.org/HowToContribute
源代码管理 ：http://wiki.openstack.org/GerritWorkflow
文档 ：http://docs.openstack.org
三、openstack架构及优势
OpenStack为私有云和公有云提供可扩展的弹性的云计算服务，这种服务云必须是简单部署并且扩展性强。
1、模块松耦合
2、组件配置较为灵活
3、二次开发容易
四、openstack构成组件
OpenStack共享服务组件：
数据库服务（ Database Service ）：MairaDB 及 MongoDB
消息传输（Message Queues）：RabbitMQ
缓存（cache）： Memcached 时间（time sync）：NTP
存储（storge provider）：ceph、GFS、LVM、ISICI等
高可用及负载均衡：pacemaker、HAproxy、keepalive、lvs等
OpenStack核心组件：
身份服务（ Identity Service ）：Keystone
计算（ Compute ）： Nova
镜像服务（ Image Service ）： Glance
网络 & 地址管理（ Network ）： Neutron
对象存储（ Object Storage ）： Swift
块存储 (Block Storage) ： Cinder
UI 界面 (Dashboard) ： Horizon
测量 (Metering) ： Ceilometer
部署编排 (Orchestration) ： Heat