云计算第五章

Posted 2022-03-24 愚生浅末

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Cloud-Enabling Technology云使能技术

Broadband Networks and Internet Architecture 宽带和Internet架构

-All clouds must be connected to a network（Internet or LAN）

The potential of cloud platforms therefore generally grows in parallel with advancements in Internet connectivity and service quality.

云平台的潜力通常是与Internet的互联互通和服务质量同步提升的。

Internet Service Providers (ISPs) Internet服务提供者

-the Internet’s largest backbone（主干） networks

Established and deployed by ISPs
interconnected by core routers
routers connect world’s multinational （跨国的）networks.

-Decentralized provisioning and management model

ISPs freely deploy, operate, manage their networks
No centralized entity governs the Internet
ICANN-互联网名称与数字地址分配机构
Governmental and regulatory laws dictate the service provisioning conditions for organizations and ISPs both within and outside of national borders.

-The Internet’s topology 拓扑

The Internet’s topology has become a dynamic and complex aggregate（集合） of ISPs ，highly interconnected via its core protocols
Three hierarchical topology

-Three hierarchical topology（图5.2）
The core Tier 1

large-scale, international cloud providers
oversee interconnected global networks
connected to Tier 2’s large regional providers

ISPs of Tier 2

connect with Tier 1 providers
connect with local ISPs of Tier 3
Tier 3 local ISPs

-Cloud consumers and cloud providers can connect directly using a Tier 1 provider

-IT resources among paths

communication links of internet and ISP networks
routers of internet and ISP networks

-Two fundamental components used to construct the internetworking architecture

connectionless packet switching (datagram networks) 无连接分组交换
router-based interconnectivity基于路由器互联

Connectionless Packet Switching (Datagram Networks)

End-to-end (sender-receiver pair) 端到端

1.data flows are divided into packets of a limited size
2.received and processed through network switches and routers
3.queued and forwarded from one intermediary node to the next
4.Each packet carries the necessary location information,
5.processed and routed at every source, intermediary, and destination node.

Router-Based Interconnectivity

-Router

1.A router is a device that is connected to multiple networks through which it forwards packet
2.routers process and forward each packet individually
3.maintaining the network topology information
4.manage network traffic and gauge估计 the most efficient

hop（弹跳） for packet delivery

-Communication path that connects cloud consumer with cloud provider may involve multi-ISP network，multiple alternative network routes that are determined at runtime

-The basic mechanics of internetworking

Figure 5.3 Packets traveling through the Internet are directed by a router that arranges them into a message

-ISPs implement the Internet’s internetworking layer and interact with other network technologies：

1、Physical Network 物理网络
2、Transport Layer Protocol 传输层协议
3、Application Layer Protocol 应用层协议

Data Center Technology 数据中心

Data Center
-Grouping IT resources in close proximity （邻近）
-Power sharing
-Higher efficiency in shared IT resource usage
-Improved accessibility for IT personnel
Modern data centers
-specialized IT infrastructure used to house centralized IT resources, such as servers, databases, networking and telecommunication devices, and software systems
Data centers are typically comprised of the following technologies and components:

1.Virtualization虚拟化
2.Standardization and Modularity标准化和模块化
3.Automation 自动化
4.Remote Operation and Management远程操作和管理
5.High Availability高可用性
6.Security-Aware Design, Operation And Management
7.Facilities配套设施
8.Computing Hardware计算硬件
9.Storage Hardware存储硬件
10.Network Hardware网络硬件

Virtualization虚拟化

Data centers IT resources：physical and virtualized
Physical IT resource layer：
-the facility infrastructure that houses computing/networking systems and equipment, together with hardware systems and their operating systems
virtualization layer:
-comprised of operational and management tools of virtualization platforms
-abstract physical computing and networking IT resources as virtualized components

easier to allocate, operate, release, monitor, and control

hypervisor
虚拟机监视器
VIM
虚拟化基础设施管理

Figure 5.7 The common components of a data center working together to provide virtualized IT resources supported by physical IT resources.

Standardization and Modularity标准化和模块化

Data centers are built upon standardized commodity hardware and designed with modular architectures
-Aggregating multiple identical building blocks of facility infrastructure and equipment
-Support scalability, growth, hardware replacement
-Modularity and standardization reducing investment and operational costs
-Consolidated IT resources can serve different systems and be shared among different cloud consumers.

Automation 自动化

Data centers have specialized platforms
-Automate provisioning, configuration, patching（打补丁）, and monitoring without supervision（监管）
-Advances in data center management platforms and tools leverage（利用） autonomic computing technologies to enable self-configuration and self-recovery.

Remote Operation and Management远程操作和管理

Most of the operational and administrative tasks of IT resources in data centers are commanded through the network’s remote consoles and management systems.
Technical personnel are not required to visit the dedicated rooms that house servers, except to perform highly specific tasks, such as equipment handling and cabling or hardware-level installation and maintenance.

High Availability 高可用性

Since any form of data center outage significantly impacts business continuity for the organizations that use their services
data centers are designed to operate with increasingly higher levels of redundancy to sustain（维持） availability.
-Data centers usually have redundant, uninterruptable power supplies, cabling, and environmental control subsystems in anticipation of system failure, along with communication links and clustered hardware for load balancing.

Security-Aware Design, Operation And Management安全感知设计、操作和管理

Since centralized structures that store and process business data
Requirements for security （thorough & comprehensive ）彻底和全面
-physical and logical access controls
-data recovery strategies

Facilities 配套设施

Data center facilities are custom-designed locations outfitted (配置)with specialized computing, storage, and network equipment
E.g.These facilities have several functional layout areas, as
well as various power supplies, cabling, and environmental
control stations that regulate heating, ventilation, air
conditioning, fire protection, and other related subsystems.

Computing Hardware 计算硬件

Much of the heavy processing in data centers is often executed by standardized commodity servers that have substantial（强大的） computing power and storage capacity.
computing hardware technologies :
-standardized racks机架 with interconnects for power, network, and internal cooling
-Support for different hardware processing architectures
-Hundreds of a power-efficient multi-core CPU architecture in unit of standardized racks
-Redundant and hot-swappable components
Computing architectures计算架构
-blade server technologies刀片服务器技术

Storage Hardware 存储硬件

Storage systems involve technologies:
-Hard Disk Arrays硬盘阵列
-I/O Caching高速缓存
-Hot-Swappable Hard Disks热插拔硬盘
-Storage Virtualization 存储虚拟化
-Fast Data Replication Mechanisms快速数据复制机制

Snapshotting快照
volume cloning卷克隆

Storage systems encompass tertiary redundancies
-direct-attached storage (DAS)直接附加存储
-Storage Area Network (SAN)存储区域网络
-Network-Attached Storage (NAS) 网络附加存储

Network Hardware 网络硬件

Five network subsystems
-Carrier and External Networks Interconnection运营商和外网互联
-Web-Tier Load Balancing and Acceleration web层均衡负载和加速
-LAN Fabric LAN光网络
-SAN Fabric SAN光网络
-NAS Gateways NAS网关

Virtualization Technology 虚拟化技术

Virtualization is the process of converting a physical IT resource into a virtual IT resource
Most types of IT resources can be virtualized
-Servers, Storage, Network, Power
Virtualization software create new virtual server
-allocation of physical IT resources
-install operating system(guest operating systems)

Unaware of the virtualization process

Host or physical host 主机或物理主机
-Virtualization software runs on a physical server
virtual machine management虚拟机管理器
-Virtualization software runs on a physical server called a host or physical host, whose underlying hardware is made accessible by the virtualization software.
-virtual machine manager or a virtual machine monitor or hypervisor 虚拟机监控器
Hardware Independence 硬件无关性
Server Consolidation 服务器整合
Resource Replication 资源复制
Operating System-Based Virtualization基于操作系统虚拟化
Hardware-Based Virtualization基于硬件虚拟化
Virtualization Management 虚拟化管理

Hardware Independence 硬件无关性

Software-hardware dependencies （原因）
-In a non-virtualized environment, the operating system is configured for specific hardware models and requires reconfiguration if these IT resources need to be modified
Virtualization → hardware independence(结果)
-translates IT hardware into emulated and standardized software-based copies.
-virtual servers can easily be moved to another virtualization host, automatically resolving multiple hardware-software incompatibility issues.
As a result, cloning and manipulating（控制） virtual IT resources is much easier than duplicating(复制) physical hardware.

Server Consolidation 服务器整合

Coordination function of virtualization software
-multiple virtual servers to be simultaneously created in the same virtualization host
server consolidation服务器整合
-Virtualization technology enables different virtual servers to share one physical server
-increase hardware utilization, load balancing, and optimization of available IT resources
-This fundamental capability directly supports common cloud features, such as on-demand usage, resource pooling, elasticity, scalability, and resiliency

Resource Replication 资源复制

Virtual servers are created as virtual disk images
-contain binary file copies of hard disk content
-These virtual disk images are accessible to the host’s operating system

Simple file operations, such as copy, move, paste, back up
virtual server
This ease of manipulation and replication is one of the most salient（突出的）features of virtualization technology

Operating System-Based Virtualization 基于操作系统虚拟化

host operating system宿主操作系统
-the installation of virtualization software in a pre-existing operating system
-Host OS can support hardware devices
-OS virtualization can rectify(解决) hardware compatibility issues
Virtualization enabled Hardware independence
-Hardware IT resources to be more flexibly used
-Virtualization software translates hardware IT resources into virtualized IT resources compatible with operating systems

Hardware-Based Virtualization基于硬件虚拟化

Hypervisor虚拟机管理程序
-Virtualization software directly install to physical host hardware bypass the host operating system
-A hypervisor has a simple user-interface, establish a virtualization management layer
-Hardware-based virtualization more efficient

enables multiple virtual servers to interact with the same hardware platform

Device drivers and system services are optimized for the provisioning of virtual servers

hardware-based virtualization concerns compatibility with hardware devices
-meaning all of the associated device drivers and support software need to be compatible with the hypervisor

Virtualization Management虚拟化管理

Virtualized IT resource management is often supported by virtualization infrastructure management (VIM) tools
-collectively manage virtual IT resources
-rely on a centralized management module
-runs on a dedicated computer

Web Technology Web技术

Web technology is generally used as both the implementation medium and the management interface for cloud services.

Basic Web Technology 基本web技术

Web Applications web应用

Basic Web Technology

Basic Web Technology
-WWW is a system of interlinked IT resources that are accessed through the Internet.
Web components
-Web browser client and Web server
3 fundamental elements of Web technology architecture :
-Uniform Resource Locator (URL)-logical network location
统一资源定位符
-Hypertext Transfer Protocol (HTTP)-communications protocol
超文本传输协议
-Markup Languages (HTML, XML)-Markup languages
标记语言
Web resources are represented as hypermedia 超媒体

Web Applications

Web application: A distributed application that uses Web-based technologies (and generally relies on Web browsers for the presentation of user-interfaces)
-A distributed application that uses Web-based technologies, be found in all kinds of cloud-based environments.
Web applications basic three-tier model

presentation layer--first tier, user-interface 表示层

application layer--middle tier, application logic 应用层

data layer--third tier, persistent data stores数据层

PaaS environments enable cloud consumers to develop and deploy Web applications, typical PaaS offerings have separate instances of the Web server, application server, and data storage server environments

Multitenant Technology 多租户技术

Multitenant application: Multiple users (tenants) to access the same application logic simultaneously
-Each tenant has its own view of the application remaining unaware of other tenants that are using the same application
-Do not access to data and configuration information that is not their own
Tenants individually customize application features:

User Interface用户界面

Business Process业务流程

Data Model 数据模型

Access Control访问控制

Support share of various artifacts（构件） by multiple users and maintaining security levels that segregate（隔离） individual tenant operational environments.
Common characteristics of multitenant applications :

Usage Isolation 使用隔离

Data Security 数据安全

Recovery 可恢复

Application Upgrades 应用升级

Scalability 可扩展性

Metered Usage 使用计量

Data Tier Isolation数据层隔离

Service Technology 服务技术

Service technology is keystone foundation of cloud computing that formed the basis of the “as-a-service” cloud delivery models.

Web Services Web服务

REST Services REST服务

Service Agents 服务代理

Service Middleware 服务中间件

Web Services

First generation Web service technologies

Web Service Description Language (WSDL)
web 服务描述语言

XML Schema Definition Language (XML Schema)
XML模式描述语言

Simple Object Access Protocol(SOAP)
简单对象访问协议

Universal Description, Discovery, and Integration (UDDI)
统一描述、发现和集成

Second-generation Web service technologies
commonly referred to as WS-*

Figure 5.12. An overview of how first-generation Web service technologies commonly relate to each other.

REST Services REST 服务

REST services are designed according to a set of constraints that shape the service architecture to emulate the properties of the WWW, resulting in service implementations that rely on the use of core Web technologies
The six REST design constraints:

Client-Server 客户端-服务器

Stateless 无状态

Cache 缓存

Interface/Uniform Contract 接口/统一合约

Layered System 层次化系统

Code-On-Demand 按需编码

Each design constraint is described in detail at www.whatisrest.com.

Service Agents 服务代理

Service agents are event-driven programs designed to intercept（拦截） messages at runtime.
-active service agent 主动服务代理

Active service agents perform an action upon intercepting and reading the contents of a message.

making changes to the message contents (most commonly message header data and less commonly the body content) or changes to the message path itself.
-passive service agent 被动服务代理

do not change message contents

they read the message and may then capture certain parts of its contents for monitoring, logging, or reporting purposes

Cloud-based environments rely heavily on system-level and custom service agents to perform runtime monitoring and measuring

Service Middleware 服务中间件

middleware platforms is the large market under the umbrella of service technology
messaging-oriented middleware (MOM) platforms → sophisticated（复杂的） service middleware platforms
two types of middleware platforms

enterprise service bus (ESB) 企业服务总线

orchestration platform 业务流程平台

Both forms of service middleware can be deployed and operated within cloud-based environments

summary

↻ Broadband Networks and Internet Architecture宽带和Internet架构
↻ Data Center Technology数据中心
↻ Virtualization Technology虚拟化技术
↻ Web Technology Web 服务
↻ Multitenant Technology多租户技术
↻ Service Technology服务技术