commonly deployed as virtualized IT environments that include:

Virtual Firewall(虛擬防火墻) – An IT resource that actively filters (過濾)network traffic to and from the isolated network while controlling its interactions with the Internet.
可以主動過濾被隔離網路的網路流量，并控制其與Internet的互動
Virtual Network (虛擬網路) – Usually acquired（形成） through VLANs, this IT resource isolates the network environment within the data center infrastructure.
用來隔離資料中心基礎設施內的網路環境

Virtual Server 虛擬服務器

A virtual server is a form of virtualization software that emulates a physical server.
虛擬服務器是一種模擬物理服務器的虛擬化軟體，
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 Storage Device 云存盤設備

The cloud storage device mechanism
represents storage devices that are designed specifically for cloud-based provisioning.
云存盤機制是指專門為基于云配置所設計的存盤設備

1.Instances of these devices can be virtualized
可以被虛擬化
2.Cloud storage devices can be exposed for remote access via cloud storage services.通過云存盤服務可以遠程訪問云存盤設備
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 云存盤等級
  -Network Storage Interfaces 網路存盤介面
  -Object Storage Interfaces 物件存盤介面
  -Database Storage Interfaces 資料庫存盤介面

Cloud Storage Levels 云存盤等級

Cloud storage device mechanisms provide common logical units of data storage:常見的資料存盤邏輯單元

.Files (檔案)– Collections of data are grouped into files that are located in folders.
2.Blocks(塊) – 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(資料集) – Sets of data are organized into a table-based, delimited, or record format.
4.Objects(物件) – Data and its associated metadata(元資料) 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
每個資料存盤等級通常都與某種型別的技術介面相關聯，這個技術介面不僅與特定的云存盤設備對應，還與顯示其API的云存盤服務對應，

Network Storage Interfaces 網路存盤介面

Legacy(傳統) 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) --用于網路設備間檔案共享
3.network file system (NFS)-- for file and network storage.網路上與他人共享目錄和檔案

Object Storage Interfaces 物件存盤介面

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.
  通常可以通過以HTTP為主要協議的REST或者基于Web服務的云服務來訪問

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

Database Storage Interfaces 資料庫存盤介面

Cloud storage device mechanisms based on database storage interfaces typically support a query language in addition to basic storage operations.
除了支持基本存盤操作外，通常還支持查詢語言

1. Storage management is carried out using ①a standard API or ②an administrative user-interface.
   通過標準API或管理用戶介面來實作存盤管理

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

Relational Data Storage 關系資料存盤
Non-Relational Data Storage 非關系資料存盤

1.Relational Data Storage 關系資料存盤

• Relational databases (or relational storage devices) rely on tables to organize similar data into rows and columns.
  關系資料庫依靠表格，將相似的資料組織為行列形式

• Working with relational storage commonly involves the use of the industry standard Structured Query Language (SQL).
  通常也要用到工業標準結構化查詢語言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.
  可以以許多可用的商業資料庫產品為基礎

• Challenges with cloud-based relational databases commonly pertain to scaling and performance.
  基于云的關系資料庫的挑戰主要來自擴展和性能

2.Non-Relational Data Storage 非關系資料存盤

• 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 (資料規范).

The primary motivation for using non-relational storage is to avoid the potential complexity（復雜性）and processing overhead(負擔) 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(專有的) and therefore can severely limit data portability（可移植性）.

Cloud Usage Monitor 云使用監控

• 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 監控代理
Resource Agent 資源代理
Polling Agent 輪詢代理

Monitoring Agent 監控代理

• 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 .

一個中間的事件驅動程式，它作為服務代理駐留在已有通信路徑上，對資料流進行透明的監控和分析，

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

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 資源代理

• A resource agent is a processing module that collects usage data by having event-driven interactions with specialized resource software.
  資源代理是一種處理模塊，通過與專門的資源軟體進行事件驅動的互動來收集使用資料，

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.
它在資源軟體級上，監控預定義的且可觀測事件的使用指標，比如：啟動、暫停、恢復和垂直擴展，

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 輪詢代理

• A polling agent is a processing module that collects cloud service usage data by polling IT resources.
  一種處理模塊，通過輪詢IT資源來收集云服務使用資料，

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監控IT資源狀態，比如正常運行時間與停機時間，

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 資源復制

• 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.

被定義為對同一個IT資源創建多個實體，通常在需要加強IT資源的可用性和性能時執行，

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

Ready-Made Environment 已就緒環境

• 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.
  已就緒環境機制是PaaS云交付模型的定義組件,它表示的是預定義的基于云的平臺，該平臺由一組已安裝的IT資源組成，可以被云用戶使用和定制，

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

• Typical ready-made environments include pre-installed IT resources, such as databases, middleware, development tools, and governance tools.
  典型的已就緒環境包括預安裝的IT資源，如資料庫、中間件、開發工具和管理工具，

• A ready-made environment is generally equipped with a complete software development kit (SDK)
  已就緒環境通常配備一套完整的軟體開發工具包，

• Middleware is available for multitenant platforms to support the development and deployment of Web applications.
  中間件用于多租戶平臺，支持開發和部署Web應用程式，

summry

• Logical Network Perimeter 邏輯網路邊界
• Virtual Server 虛擬服務器
• Cloud Storage Device 云存盤設備
• Cloud Usage Monitor 云使用監控
• Resource Replication 資源復制
• Ready-Made Environment 已就緒環境
• Cloud Storage Levels 云存盤等級
• Network Storage Interfaces 網路存盤介面
• Object Storage Interfaces 物件存盤介面
• Database Storage Interfaces資料庫存盤介面
• Monitoring Agent 監控代理
• Resource Agent 資源代理
• Polling Agent 輪詢代理

個人博客本文地址：https://kohler19.gitee.io/2022/03/31/cloud-computing5/

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