云计算第七章

Cloud Infrastructure Mechanisms云基础设施机制

The following cloud infrastructure mechanisms are described in this chapter:
--Logical Network Perimeter 逻辑网络边界
--Virtual Server 虚拟服务器
--Cloud Storage Device 云存储设备
--Cloud Usage Monitor 云使用监控
--Resource Replication 资源复制
--Ready-Made Environment 已就绪环境
they should be viewed as core components that are common to cloud platforms.

Logical Network Perimeter 逻辑网络边界

Defined as the isolation of ①a network environment from the rest of a communications network, ②the logical network perimeter establishes a virtual network boundary that can encompass and ③isolate a group of related cloud-based IT resources that may be physically distributed

逻辑网络边界被定义为将一个网络环境与通信网络的其他部分隔离开来。（逻辑网络是指一个单独的网络或一个子网）
成一个虚拟网络边界,包含并隔离了一组相关的基于云的IT资源（物理上可能是分布式的）

This mechanism can be implemented to:

1.isolate IT resources in a cloud from non-authorized users
与非授权用户隔离
2.isolate IT resources in a cloud from non-users
与非用户隔离
3.isolate IT resources in a cloud from cloud consumers
与云用户隔离
4.control the bandwidth that is available to isolated IT resources
控制被隔离IT资源的可用带宽（从通讯路径角度）

Logical network perimeters are typically established via network devices that supply and control the connectivity of a data center
通常由提供和控制数据中心连接的网络设备来建立。

commonly deployed as virtualized IT environments that include:

Virtual Firewall(虚拟防火墙) – An IT resource that actively filters (过滤)network traffic to and from the isolated network while controlling its interactions with the Internet.
可以主动过滤被隔离网络的网络流量，并控制其与Internet的交互
Virtual Network (虚拟网络) – Usually acquired（形成） through VLANs, this IT resource isolates the network environment within the data center infrastructure.
用来隔离数据中心基础设施内的网络环境

the boundary of a logical network perimeter a virtual firewall a virtual network
Virtual Server 虚拟服务器

A virtual server is a form of virtualization software that emulates a physical server.
虚拟服务器是一种模拟物理服务器的虚拟化软件。
As a commodity mechanism, the virtual server represents the most foundational building block of cloud environments. Each virtual server can host numerous IT resources, cloud-based solutions, and various other cloud computing mechanisms.
The number of instances a given physical server can share is limited by its capacity.
Cloud consumers that install or lease virtual servers can customize their environments independently from other cloud consumers. 云用户可以定制自己的环境 Virtual servers are created via the physical servers’ hypervisors and a central VIM.
Cloud Storage Device 云存储设备

The cloud storage device mechanism
represents storage devices that are designed specifically for cloud-based provisioning.
云存储机制是指专门为基于云配置所设计的存储设备

1.Instances of these devices can be virtualized
可以被虚拟化
2.Cloud storage devices can be exposed for remote access via cloud storage services.通过云存储服务可以远程访问云存储设备
3.A primary concern related to cloud storage is the security, integrity, and confidentiality of data
4.LANs provide locally stored data with network reliability and latency levels that are superior to those of WANs.

Cloud storage device mechanisms provide common logical units of data storage, such as:
-Cloud Storage Levels 云存储等级
-Network Storage Interfaces 网络存储接口
-Object Storage Interfaces 对象存储接口
-Database Storage Interfaces 数据库存储接口

Cloud Storage Levels 云存储等级

Cloud storage device mechanisms provide common logical units of data storage:常见的数据存储逻辑单元

.Files (文件)– Collections of data are grouped into files that are located in folders.
2.Blocks(块) – The lowest level of storage and the closest to the hardware, a block is the smallest unit of data that is still individually accessible.
3.Datasets(数据集) – Sets of data are organized into a table-based, delimited, or record format.
4.Objects(对象) – Data and its associated metadata(元数据) are organized as Web-based resources.

Each of these data storage levels is commonly associated with a certain type of technical interface which corresponds to a particular type of cloud storage device and cloud storage service used to expose its API
每个数据存储等级通常都与某种类型的技术接口相关联，这个技术接口不仅与特定的云存储设备对应，还与显示其API的云存储服务对应。
Different cloud service consumers utilize different technologies to interface with virtualized cloud storage devices.
Network Storage Interfaces 网络存储接口

Legacy(传统) network storage most commonly falls under the category of network storage interfaces. It includes storage devices in compliance（遵守）with industry standard protocols.

1.SCSI -- storage blocks and the server message block (SMB),
2.common Internet file system (CIFS) --用于网络设备间文件共享
3.network file system (NFS)-- for file and network storage.网络上与他人共享目录和文件

Object Storage Interfaces 对象存储接口

object storage---Various types of data can be referenced and stored as① Web resources. which is ②based on technologies that can support a range of data and media types.

Object Storage Interfaces can is typically be accessed via REST or Web service-based cloud services using HTTP as the prime protocol.
通常可以通过以HTTP为主要协议的REST或者基于Web服务的云服务来访问

The Storage Networking Industry Association’s Cloud Data Management Interface (SNIA’s CDMI) supports the use of object storage interfaces.

Database Storage Interfaces 数据库存储接口

Cloud storage device mechanisms based on database storage interfaces typically support a query language in addition to basic storage operations.
除了支持基本存储操作外，通常还支持查询语言

Storage management is carried out using ①a standard API or ②an administrative user-interface.
通过标准API或管理用户接口来实现存储管理

This classification of storage interface is divided into two main categories according to storage structure:

Relational Data Storage 关系数据存储
Non-Relational Data Storage 非关系数据存储

1.Relational Data Storage 关系数据存储

Relational databases (or relational storage devices) rely on tables to organize similar data into rows and columns.
关系数据库依靠表格，将相似的数据组织为行列形式

Working with relational storage commonly involves the use of the industry standard Structured Query Language (SQL).
通常也要用到工业标准结构化查询语言SQL

A cloud storage device mechanism implemented using relational data storage could be based on any number of commercially available database products, such as IBM DB2, Oracle Database, Microsoft SQL Server, and MySQL.
可以以许多可用的商业数据库产品为基础

Challenges with cloud-based relational databases commonly pertain to scaling and performance.
基于云的关系数据库的挑战主要来自扩展和性能

2.Non-Relational Data Storage 非关系数据存储

Non-relational storage (also commonly referred to as NoSQL storage)

it establishes a “looser” structure for stored data with less emphasis on defining relationships and realizing data normalization (数据规范).

The primary motivation for using non-relational storage is to avoid the potential complexity（复杂性）and processing overhead(负担) that can be imposed by relational databases.

non-relational storage can be more horizontally scalable than relational storage.

However, many non-relational storage mechanisms are proprietary(专有的) and therefore can severely limit data portability（可移植性）.

Cloud Usage Monitor 云使用监控

The cloud usage monitor mechanism is a lightweight and autonomous（自治的）software program responsible for collecting and processing IT resource usage data.

Three common agent-based implementation formats:

Monitoring Agent 监控代理
Resource Agent 资源代理
Polling Agent 轮询代理

Monitoring Agent 监控代理

A monitoring agent is an intermediary, event-driven program that exists as a service agent and resides along existing communication paths to transparently monitor and analyze dataflows .

一个中间的事件驱动程序，它作为服务代理驻留在已有通信路径上，对数据流进行透明的监控和分析。

This type of cloud usage monitor is commonly used to measure network traffic and message metrics(指标)

A cloud service consumer sends a request message to a cloud service (1).
The monitoring agent intercepts the message to collect relevant usage data (2) before allowing it to continue to the cloud service (3a). The monitoring agent stores the collected usage data in a log database (3b). The cloud service replies with a response message (4) that is sent back to the cloud service consumer without being intercepted by the monitoring agent (5).

Resource Agent 资源代理

A resource agent is a processing module that collects usage data by having event-driven interactions with specialized resource software.
资源代理是一种处理模块，通过与专门的资源软件进行事件驱动的交互来收集使用数据。

This module is used to monitor usage metrics based on pre-defined, observable events at the resource software level, such as initiating, suspending, resuming, and vertical scaling.
它在资源软件级上，监控预定义的且可观测事件的使用指标，比如：启动、暂停、恢复和垂直扩展。

The resource agent is actively monitoring a virtual server and detects an increase in usage (1). The resource agent receives a notification from the underlying resource management program that the virtual server is being scaled up and stores the collected usage data in a log database, as per its monitoring metrics (2).

Polling Agent 轮询代理

A polling agent is a processing module that collects cloud service usage data by polling IT resources.
一种处理模块，通过轮询IT资源来收集云服务使用数据。

This type of cloud service monitor is commonly used to periodically monitor IT resource status, such as uptime and downtime .
它通常被用于周期性地监控IT资源状态，比如正常运行时间与停机时间。

A polling agent monitors the status of a cloud service hosted by a virtual server by sending periodic polling request messages and receiving polling response messages that report usage status “A” after a number of polling cycles, until it receives a usage status of “B” (1), upon which the polling agent records the new usage status in the log database (2).

Resource Replication 资源复制

Defined as the creation of multiple instances of the same IT resource, resource replication is typically performed when an IT resource’s availability and performance need to be enhanced.

被定义为对同一个IT资源创建多个实例。通常在需要加强IT资源的可用性和性能时执行。

Virtualization technology is used to implement the resource replication mechanism to replicate(复制 ) cloud-based IT resources .

The hypervisor replicates several instances of a virtual server, using a stored virtual server image.
Ready-Made Environment 已就绪环境

The ready-made environment mechanism is a defining component of the ①PaaS cloud delivery model that represents a ②pre-defined, cloud-based platform comprised of a set of already installed IT resources, ready to ③be used and customized by a cloud consumer.
已就绪环境机制是PaaS云交付模型的定义组件,它表示的是预定义的基于云的平台，该平台由一组已安装的IT资源组成，可以被云用户使用和定制。

These environments are utilized by cloud consumers to remotely develop and deploy their own services and applications within a cloud.

A cloud consumer accesses a ready-made environment hosted on a virtual server.

Typical ready-made environments include pre-installed IT resources, such as databases, middleware, development tools, and governance tools.
典型的已就绪环境包括预安装的IT资源，如数据库、中间件、开发工具和管理工具。

A ready-made environment is generally equipped with a complete software development kit (SDK)
已就绪环境通常配备一套完整的软件开发工具包。

Middleware is available for multitenant platforms to support the development and deployment of Web applications.
中间件用于多租户平台，支持开发和部署Web应用程序。

summry

Logical Network Perimeter 逻辑网络边界

Virtual Server 虚拟服务器

Cloud Storage Device 云存储设备

Cloud Usage Monitor 云使用监控

Resource Replication 资源复制

Ready-Made Environment 已就绪环境

Cloud Storage Levels 云存储等级

Network Storage Interfaces 网络存储接口

Object Storage Interfaces 对象存储接口

Database Storage Interfaces数据库存储接口

Monitoring Agent 监控代理

Resource Agent 资源代理

Polling Agent 轮询代理

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