Cloud computing-from basic to application architecture series-virtualization Concept

ArticleDirectory

• Opening
• Summary
• Outline
• Concept of Virtualization
• Virtualization Classification
• Server Virtualization
• Summary
• Follow-up

 

Opening

In the previous article, we talked about the development history of cloud computing and, of course, a future trend of the IT Information Industry. Just as our Internet applications are booming, there are currently some rich clients in RIA.

The rapid development of the application, including the future promotion of open-source software and HTML5, is undoubtedly to provide better services for users. Of course, the proposal of cloud computing is also on the shoulders of our predecessors.

Some technologies are a new IT mode that provides better services for users or enterprises. Therefore, we can say that cloud computing brings about a change in the IT industry landscape. Therefore, what we hold about cloud computing

Attitude may not say it is not an option, but we must be able to put me in our own enterprise informatization decisions, it can be listed as one of the important strategies for future enterprise development.

This article will introduce the underlying core technology virtualization concepts of the emerging concept of cloud computing from one of the core technologies of cloud computing. At least we should know the concept of cloud computing.

Romantic terms: what technologies are used at the underlying implementation level, what needs are used, and how such concepts are promoted. A detailed introduction to the concept of cloud computing, we are already in the first article

Mentioned above, so we only need to know that virtualization is one of the core technologies for cloud computing.

Summary

The emergence of virtualization technology is also a trend and inevitable phenomenon in the development of computer technology. It plays an important role in the development of computer technology. virtualization technology was launched as early as 1950s.

It has been suggested that the first time virtualization technology was applied to commercial applications in the 1960s S, and the first company in the business was IBM.

I have always been a leader in virtualization technology. Now there are too many places to use virtualization technology. For example, whether it is the virtual memory of the operating system, the virtual machine or the current service

Virtual Machine or PC virtualization are inseparable from virtualization technology. With the widespread use of virtualization technology, it brings new management and deployment methods for data centers and Application Deployment. virtualization technology

It improves efficient and convenient management and resource utilization. virtualization technology has become an important enterprise strategy for many business giants.

This article will elaborate on the following aspects.

1. Concepts of Virtualization

2. Common Types of Virtualization

3. Virtualization

Outline

1. Opening

2. Summary

3. Outline

4. Concepts of Virtualization

5. common types of Virtualization

6. Evolution of Virtualization Technology

7. Server Virtualization

8. Summary

9. Follow-up

10. References

Concept of Virtualization

The concept of virtualization is relative to actual resources. Simply put, virtualization is to simulate the full state of running in the real environment to a virtualized environment.

We know that there are two types of computer resources: hardware resources and software resources.

Virtualization Technology Applies virtualization technology to computer resources. Therefore, it can be applied to both hardware and software. Generally, the structure of computer hardware and software resources may be as follows:

Condition:

The above figure shows a set of virtualized computer resources, which basically covers virtualized resources.

If you have read the computer operating system teaching materials, you should know the memory virtualization technology in the operating system.

How can this be understood? I think we can use the virtualization technology to explain it. The idea of virtual memory in the operating system is that the operating system does not use the memory in a certain area of the hard disk.

Status data Io to the hard disk, wait forProgramWhen the data to be used is not in the memory, I/O operations are performed to Io the applied data into the memory. Even if our memory is small

However, we can run a program with a large amount of data because we didn't load all the data in the memory at a time, which is similar to the delay loading of our applications.

However, different ideas cannot be confused. Next we will briefly describe the process.

 

Here, some memory space in the memory is released and provided to the program to be run. The specific Io data in the hard disk is switched according to some policies. I will not describe this topic in detail here.

For details, please refer to the relevant materials.

Let's take a look at the conceptual definition of virtualization.

1. Wikipedia's description of Virtualization

Virtualization is a way to abstract computer resources. By virtualizing computer resources, we can access virtualized resources in the form of virtualized access to material resources.

Source. In addition, such abstract resources will not be affected by factors such as resource allocation, region, and implementation.

2. Information technology Glossary

Virtualization is the virtual version of some things, such as the operating system, computer system, cup, memory, hard disk, Server Load balancer, and router.

3. IBM virtualization Definition

Virtualization is the logical representation of resources and is not subject to physical restrictions.

Through the above summary, it is not difficult to find the commonalities between them.

A. virtualization objects are various types of resources.

B. the virtualized logical resources hide some detailed maintenance.

C. Users can use some or all of the functions in the real environment in the virtual environment.

Virtualization Classification

There are a variety of virtualized resources. We have also provided the analysis based on hardware and software, which is generally in the form of a combination of hardware and software. Next we will classify the data based on Virtualization.

Let's take a simple analysis of the specific roles and functions of different types of virtualization resources for each type of virtualization. Let's take a look at the overall structure of virtualized resources.

At the beginning of this article, we split the virtualized hardware and software resources. Next we will classify the split results and describe them from the following types. Let's take a look at the infrastructure.

CATEGORY content.

1. Infrastructure Virtualization

Among these virtualized resources, I think the most common virtualization practice is-according to the virtual machine provided by VMware Workstation, we perform a logical operation by virtualizing the Virtual Machine

As a system and a virtualized operating system, we can use a virtualized operating system like a normal operating system. This virtualized Operating System is an independent operating system, we

You need to reinstall the corresponding software for the Virtual Operating System,

We usually consider data files, network resources, and storage resources as infrastructure virtualization. Network virtualization refers to integrating hardware and software resources in the network for users.

Provides virtualization network connection technology. For Network virtualization technology, we can divide it into LAN virtualization and Wan virtualization. Lan virtualization is to virtualize multiple networks in the LAN into one

A logical network, or a LAN, is divided into multiple subnets to provide network resource utilization. A typical example of Wan virtualization is VPN, by Using VPN technology, I

They can remotely access the company's internal network resources, just like access within the company. At the same time, such technology ensures the security and privacy of external network connections.

Storage-based virtualization technology refers to providing an abstract logical view for physical devices. Users can access integrated resources through this view. A typical example of this technology is a disk array.

Technology (RAID) This technology combines multiple physical hard disks into a disk array and combines them into a high fault tolerance and high-performance storage space with inexpensive devices.

Ii. Operating System Virtualization

I think most of our IT colleagues may not fully understand the virtualization technology before we fully understand it. We have a lot of knowledge about the operating system.

Virtualization is virtualization, memory Virtualization in the operating system, and printer virtualization. System virtualization achieves the separation of the operating system and physical devices. For example, we can

We know that a computer cannot run multiple physical operating systems at the same time when installing a Linux operating system on a Windows operating system. However, with the virtualization technology, we can

I think you have the most profound understanding.

By using virtual machines to create multiple operating system instances, we can run multiple system instances in the computer to run multiple system instances simultaneously.

Virtual machines, we need to provide virtual resources for the Virtual Machine runtime environment.

We can see that the running devices under the virtual machine are provided to the Virtual Machine runtime environment by allocating the corresponding computer resources from the physical resources of the computer.

When using an operating system instance in a virtual machine, it is as convenient as our physical operating system.

In addition, through the virtualized operating system, if we install some of our applications on the virtual machine, we can restore the mirror by creating snapshots and Machine images.

For example, the virtual machine instance is restored from the snapshot. Generally, it takes only a few minutes to restore an instance. In this way, we can quickly restore an operating system or save

Unnecessary waste of time by application.

Iii. Software Virtualization

In addition to the two virtualization types mentioned above, there is also a virtualization technology of the application type. By using the software virtualization technology, we can achieve decoupling between the software and the operating system,

Provide a virtual runtime environment for the software. For example, in the following scenario, we now develop an application. We deploy the corresponding components on the virtualized server. When the user accesses the relevant application

In sequence, we use the virtualization server to push components to the virtual environment of the client to complete the application. When the customer closes the software, the customer's changes and data are sent back to the virtual service.

In this way, the user can not only be limited to a single client, but also use their own applications on different terminals.

A typical software virtualization technology is represented by Java virtual machines.Programming LanguageCompiled into an intermediate language. The Java Virtual Machine interprets the intermediate language as a specific platform.

The executable binary machine code achieves a compilation and runs everywhere, but of course this is the goal and there may be some details to deal.

I will not give other examples here, so we can look at the simple process of implementing application virtualization.

Server Virtualization

Server virtualization technology. In the previous article, we talked about the concept of server virtualization and analyzed three core technologies of server virtualization: cup, memory, device, and Io. This section

This article describes the advantages and features of these three aspects.

1. CPU

CPU virtualization technology abstracts physical CPUs into virtual CPUs. We know that physical CPUs can only process one command at any time. We also know that time-sharing CPUs pass through CPU

The execution time to respond to multiple commands, and continuously switch and execute different commands. We used a centralized server model early on, that is, a central server with multiple customers.

At the user end, each client accesses the CPU in the server to respond to their own commands. At this time, when the customer is using a computer, they do not feel that they are using a centralized server.

The use of a separate PC, at this time, we can say that the internal has actually had the concept of virtualization.

The following problems may occur during the process of CPU virtualization. Sometimes, if we execute commands like interrupt or memory management in the virtual machine,

We actually want to access physical resources, so how can we handle such problems, we can only monitor such operations through the Virtual Machine monitor. Then execute the corresponding processing.

Under the X86 architecture, there are two methods for CPU Virtualization: full virtualization and semi-virtualization. Let's introduce the principles of these two types of virtualization.

Full Virtualization: we monitor user operations through the Virtual Machine monitor. When a user executes some special commands, the Virtual Machine monitor dynamically converts these commands

The same sequence of commands that can be completed by machines. In general, full virtualization uses a binary dynamic translation mechanism. Through this mechanism, the customer feels that his system is running in the real physical environment.

.

Semi-Virtualization: enables a virtual machine to execute special commands in a real physical environment through a super call. Semi-virtualization requires the customer's operating system to be compatible with the Virtual Machine. Otherwise, if

The virtual machine cannot control the physical operating system, so the super call operation cannot be completed.

As long as the virtualization technology is adopted, it will cause performance loss. With the development of the Virtual Machine technology, the current CPU manufacturers absolutely represent intel and AMD have already integrated hardware-assisted virtualization technology

The CPU, Intel's intel-VT, AMD-V, through the CPU Hardware auxiliary technology, is to provide a collection of virtualization operations related commands, these sets of commands to help complete the preceding

Problems solved in virtualization and semi-virtualization.

2. Memory and device, Io

This section will not be described in this chapter. Basically, it is similar to the virtualization application described in the computer operating system. I will not detail it here.

Summary

This chapter describes the concepts related to virtualization, introduces the categories of virtualization resources and several types of virtualization, and analyzes the advantages of virtualization. Through virtualization technology, we provide

Resource Utilization improves system performance. With the continuous development of hardware and software, virtualization technology will play an increasingly important role in the IT industry.

The only difference is the deeper understanding, the more confident the future IT development direction.

Follow-up

In the next article, we will start to talk about the virtualization technology. I hope that after reading the content in this chapter, if you have any comments and suggestions, please come up with me. When I write the next article, I will try it in time.

Improvement. Thank you for your comments. Due to your limited personal level, please give more advice on errors or deficiencies.