Reading Notes-Chapter 2 Introduction to Virtualization

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Introduction to Virtualization

• Virtualization Definition
  • IBM: virtualization is the logical representation of resources and is not subject to physical constraints.
  • Common virtualization types
    • Infrastructure Virtualization
      • Network Virtualization
      • Storage Virtualization
    • System virtualization (VM)
    • Software Virtualization (Java)
• Server Virtualization
  • Basic Concepts
    • Server virtualization applies system virtualization technology to servers and virtualizes a server into several servers.
    • It was first used by IBM in the mainframe. VMWare introduced it to x86pingtai in 1990s.
      
    • Widely used
      • Citrix xen
      • IBM powervm and zvm
        • The power Vm and zvm correspond to the pseries and Z Series servers. These servers are designed to test how to virtualize multiple servers.
      • Microsoft Virtual PC, virtualserver, and hyper-V
      • VMware's VMware Server, VMWare Workstation, vmwareplayer, and VMWare ESX Server
  • Typical implementation
    • Host Virtualization
      • Virtual Machine monitor is an application running on the host operating system.
    • Native Virtualization
      • The virtualization platform runs directly on the hardware.
  • Key features
    • Multiple instances
      • One physical server can run multiple virtual servers and support multiple customer Operating Systems
    • Isolation
      • One virtual machine is completely isolated from other virtual machines
    • Encapsulation
      • A complete virtual machine environment represents a single external entity
    • High Performance
      • The overhead of the Virtual Machine monitor must be controlled within the tolerable range.
  • Core Technologies
    • CPU Virtualization
      • Pure software Virtualization
        • Full Virtualization
          • Binary Code dynamic translation technology
          • Virtual Machine monitors "cheat" virtual machines at critical times, making the customer's operating system think they are running in a real physical environment
          • Advantage: code conversion is completed dynamically without the need to modify the customer's Operating System
        • Semi-Virtualization
          • The virtual machine executes privileged commands by modifying the customer's operating system.
          • The customer's operating system guides him to take the initiative to cooperate with the Virtual Machine monitor in a virtualized environment
          • Call the virtualization platform as needed to execute sensitive commands.
          • The customer's operating system and virtualization platform must be compatible
      • Hardware-aided Virtualization
        • The CPU supporting virtualization technology adds a new instruction set and processor running mode to complete functions related to CPU virtualization.
        • Intel: Intel vt
        • AMD: AMD-V
    • Memory Virtualization
      • Memory is the device with the most frequent access to virtual machines, which is equally important to CPU virtualization.
      • Implementation Method
        • Shadow page table method
          • VMware Workstation
          • VMware ESX Server
          • KVM
        • Page Table Writing Method
          • Xen
    • Device and I/O Virtualization
    • Live migration)
  • Performance Analysis
    • Performance Analysis on resource utilization by Application
      • CPU intensive)
      • Memory-intensive (Memory Intensive)
      • Input/Output-intensive (I/O intensive)
      • Lab results
        • CPU-intensive less than 5%
        • Memory-intensive less than 5%
        • I/O-intensive
    • Evaluate the service quality
      • Throughput
      • Response time
    • Conclusion
      • First, server virtualization will introduce certain system overhead, but will continue to decrease.
      • Second, there are some differences between various implementation technologies of server virtualization.
      • Third, the mainframe server virtualization technology has obvious advantages over the X86 server virtualization technology
      • Fourth, it is necessary to conduct actual test and Optimization for its application before it can be launched.
  • Technical advantages
    • Reduce operation costs
      • This frees the system administrator from a lot of heavy management work related to physical servers, operating systems, middleware, and compatibility issues.
    • Improve application compatibility
    • Accelerate Application Deployment
      • Virtual machines that directly deploy encapsulated operating systems and applications
    • Improve Service Availability
      • Service Availability refers to the ability of services to run continuously and reliably.
      • Because the virtual machine is a single logical file, it facilitates backup and migration.
    • Improve resource utilization
      • It can be said that the original multiple servers are integrated into one physical server to improve usage.
    • Dynamic Resource Scheduling
      • With the capability of real-time migration, each virtual machine can be freely moved in the pool
      • Allows you to instantly adjust VM resources.
    • Reduce energy consumption
      • Disabling servers with low utilization is the most intuitive way to save energy and reduce emissions
      • This provides the possibility of Unbinding physical servers.
• Other Virtualization Technologies
  • Network Virtualization
    • Virtual LAN
    • Virtual Private Network
    • Recently, multiple virtual network devices can run on the same network device, such as firewalls, VoIP, and mobile services.
  • Storage Virtualization
    • Raid
    • NAS
    • San
  • Desktop virtualization
  • Application Virtualization
    • Solve the Problem of program dependency on the Operating System
    • Abstracts application dependencies on underlying systems and hardware to eliminate coupling between applications and operating systems and hardware.