Virtualisation and Related Concepts in Cloud Computing.pdf
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This ppt explains an important concept of virtualization and related concepts in cloud computing.
Virtualisation and Related Concepts in Cloud Computing.pdf
- 1. VIRTUALISATION IN CLOUD COMPUTING by Amol S. Gaikwad Lecturer Government Polytechnic Gadchiroli Maharashtra
- 2. Learning Outcomes Explain characteristics of Cloud computing Compare Cloud deployment models on the given services Explain the given service offered by identified Cloud service model Explain components of Cloud computing architecture
- 3. Virtualization Virtualization - virtual word means something which is not real, not actual, not physical Virtualization is technology in which physical resources are made available as virtual resources Cloud computing uses virtualization technology to create virtual servers, virtual storage, virtual network and virtual applications Virtual server is created from physical server using virtualization software Many virtual servers can be created on a single physical server
- 4. Virtualization Reference Model Virtualization tool Virtualization layer Host means physical resources Database server storage Physical server application used by guest Physical resources Application 1 Virtual image Application 2 Fig : Virtualisation reference model
- 5. Virtualization reference model Virtualization model consist of host or physical (actual) resources in the first layer, virtualization tool in second layer and applications, virtual image and guest in third layer as shown in figure Physical machine can be virtualized as virtual machine like application-1, application-2 and virtual image as shown in figure Each virtual machine has its own operating system, system software and and applications System software are those software which controls computer hardware and other applications. Application software are those software which perform some particular task
- 6. Virtualization reference model Virtual machines are managed by virtual machine manager software Virtual machine has many virtual hardware tools which are added at the time of creating virtual machine (VM)
- 7. Virtualization Advantages of virtualization - Device connected to the network can access any network application over any network - It separates workload of one application from another application which improves security - Virtualization of an application allows users to be comfortable with different versions of the operating system - Multiple instances of application can run on multiples machines at a same time (concurrency) - It optimizes the use of single system - It improves reliability or availability of an application through repetition (redundancy)
- 8. Virtualization Disadvantages of virtualization - Managing virtualized environment is complex and very difficult task than managing physical environment - Virtualized environment uses hypervisor, if it is attacked it can affect all the virtual machines running on that host. - If virtual machines are not properly configured it can cause unauthorized access - If there is large demand then virtualized server can impact other VMs running on same machine (bottleneck) - Scalability (expansion) depends on available physical (actual) infrastructure
- 9. Virtualization Disadvantages of virtualization - Virtualization can reduce costs in the long time but the initial (starting) setup costs for storage and servers can be higher than a common setup - Data is hosted (stored) on third party resource which put's our data in vulnerable condition, any hacker can attack the data - When working on cloud, organizations required skill IT staff. If the IT staff is not skilled then organization have to provide training to them which increases cost for the company
- 11. Server/Compute Virtualization Server/compute virtualization in cloud computing means creating virtual edition of actual device or resources such as - server, storage device, network or operating system Server virtualization hides the actual resources from users, it hides physical resources such as physical server, operating system, processor details etc. Server manager with the help of application software separates one physical server and attaches it to remote virtual resources Each virtual server has its own operating system, and is virtual server is rebooted separately from other servers Server virtualization saves space by combining many servers into a single server Server virtualization removes server limit, helps in data retrieval, server management and server accessibility
- 12. Server/Compute Virtualization VIM (Virtualization Infrastructure Management ) Load Balancer Live migration program (if required) Physical Server Virtualization tool Virtual Servers A B C Fig : Server/Compute Virtualization
- 13. Server/Compute Virtualization Some time dynamic migration is started due to many reasons such as load balancing, energy saving etc. Load balancer software keep tracks of various requirements and resources allotted to user
- 14. Server/Compute Virtualization It is a method of abstracting or concealing (hiding) physical hardware from the operating system. Various OS can run at a same time one or more physical machines It divides the resources into one or more parts (environment) for execution Example of virtualization - partitioning of hard disk Virtualized resources can interact with user as a single logical resources It helps us to work on various platforms In cloud environment there is load balancer that monitor various hardware tools and to provide improved and consistent service to cloud users Server virtualization strategies - virtual machine model, paravirtual machine model and virtualization supported by OS
- 15. Server/Compute Virtualization A virtual machine (VM) is a computing system like a physical (actual) machine which controls an application and operating system (OS) An OS which runs on virtual machine is called as guest operating system Virtualization layer acts as an interface between virtual machine (VM) and hardware This virtualization layer is also called as hypervisor, it provides hardware resources to various virtual machines With cloud computing and virtualization we can enhance consistency by removing a particular point of failure Virtual Machine (VM)
- 16. Virtual Machine (VM) Only one OS runs on a single virtual machine Every virtual machine is independent (autonomous) and runs its own applications Various components of virtual machine are as below :- Virtual central processing unit (vCPU) - one or more vCPUs in VM and it can be increased / decreased according to our needs Virtual random access memory (vRAM) - It is quantity of memory given to VM, we can change it according to our needs Virtual disk - It saves OS, application, data, files etc of a VM. Every VM should have at least one virtual disl
- 17. Virtual Machine (VM) Virtual network adaptor (vNIC) - It connects virtual machine with physical machine and one virtual machine with another virtual machine on same or different computers.It works like a physical (actual) NIC card. Virtual SCSI (Small Computer System Interface) controller - It is used to retrieve virtual disks Virtual USB Controllers - It connects VM to physical USB controller and for using related USB tools Virtual machine console - It provides screen functionalities where we commands to OS
- 18. Need of Server/Compute Virtualization Server/compute virtualization allows multiple operating systems and applications to work on same physical system It reduce charges and improves consumption (utilization) of resources It dynamically allocates resources to various VMs Resource management stops virtual machines from dominating resources and provides acceptable level of services When a single OS is installed per physical machine then the hardware and OS are tightly coupled and cannot be separated Without virtualization compute systems are underutilized
- 19. Server/Compute Virtualization Advantages of server/computer virtualization - Server consolidation - muliple virtual machines can work on single physical server - Segregation - One virtual machine cannot access other other virtual machine. They work independently and when one VM fails other VM works without any changes on same physical machine - Encapsulation - it means set of virtual hardware resources, applications and operating systems grouped into a virtual machine. It makes VM portable and comfortable to use - Virtual machine does not depend on core physical hardware
- 20. Server/Compute Virtualization Advantages of server/computer virtualization - Consistency - Service is available when required - Energy efficient - reduces power consumption - Better disaster recovery - Cost savings - reduces cost on IT infrastructure, power, maintenance and cooling Techniques of serve/compute virtualization - 1) Full Virtualization 2) Para Virtualization 3) Hardware Assisted Virtualization
- 21. Hypervisor Hypervisor Hardware VM-1 VM-2 VM-3 VM-1 VM-2 VM-3 Hypervisor Operating system Server Fig : Hypervisor Type 1 Fig : Hypervisor Type 2
- 22. Hypervisor Hypervisor is a program that allows multiple operating systems to share hardware of a single system(host) Every operating system uses the host machine’s resources such as memory, processor, storage etc. for itself Guest operating systems do not disturb each other and demands of every guest OS is satisfied at a same time Hypervisor is a virtualization software It is the main component of data center consolidation Hypervisor has two main components - virtual machine monitor (VMM) and kernel
- 23. Hypervisor Hypervisor kernel provides services similar to operating system like file management, process creation, process scheduling, I/O support, resources scheduling and many others. It supports multiple virtual machines (VM) A virtual machine monitor (VMM) is responsible for executing instructions on CPU and carrying out binary translation (BT) Every virtual machine is allocated a VMM which has the share of I/O tools, CPU and memory When virtual machine begins working then the control is transferred to VMM VMM starts to execute the commands from the virtual machine (VM) Hypervisor are categorized into two types - Type 1 (Bare-metal hypervisor) and Type 2 (Hosted hypervisor)
- 24. Hypervisor Type 1 (Bare-metal hypervisor) - It is directly installed x86 supported hardware. They can directly use hardware resources. Hence it is more efficient than hosted hypervisor. Examples - Hyper-V, Xen Type 2 (Hosted hypervisor) - It is installed and works as an application on the operating system. It supports wide range of hardware configuration (settings). Examples - Virtualbox (oracle), KVM
- 25. Network Virtualization Physical Network connection Virtual network-1 Virtual network-2 Database Server Fig : Network Virtualization
- 26. Network Virtualization In network virtualization multiple virtual networks run with the help of a physical (actual) network In network virtualization physical network is logically segmented and logically grouped together to create multiple networks called as virtual network These virtual networks works as separate networks but share physical network resources A virtual network looks like a phyiscal network to a computer connected to it Two nodes (computers) connected to a virtual network can may communicate with each other even they are in different network
- 27. Network Virtualization In network virtualization multiple virtual networks run with the help of a physical (actual) network In network virtualization physical network is logically segmented and logically grouped together to create multiple networks called as virtual network These virtual networks works as separate networks but share physical network resources A virtual network looks like a phyiscal network to a computer connected to it Two nodes (computers) connected to a virtual network can may communicate with each other even they are in different network
- 28. Network Virtualization Network traffic must be navigated when two nodes (computers) in different virtual networks are communicating, even if they are connected to same physical network Network broadcast is sent to only nodes in same virtual network and not to other virtual networks Nodes in different geographical location can be grouped together to create a virtual network Network virtualization includes virtualization of both virtual machine (VM) and physical network
- 29. Network Virtualization Physical network consists of - routers, hubs, switches, repeaters, adapters and bridges A VM network exists within physical server, It contains logical switches called as ‘virtual switches’ which work same as physical switches. A VM network exists within physical server, It contains logical switches called as ‘virtual switches’ which work same as physical switches. VM communicate with each other using VM network which is inside physical server For communication between two VMs in different physical servers and VM and its users, the VM traffic should pass through both physical networks and VM
- 30. Tools used in Network Virtualization Following tools are used to develop virtual networks on virtual machines (VMs) and physical networks physical switch operating system hypervisor
- 31. Benefits/Advantages of Network Virtualization Network virtualization provides better security by restricting access to nodes placed inside virtual network from other virtual networks Nodes in virtual network are arranged as per the requirements of the company Multiple resources share same physical network, this increases consumption (utilization) of resources Reduction of hardware expenses - network virtualization reduces expenses on hardware Energy expenses - virtualization reduces electricity utilization Recoverability - We can quickly recover from any hardware failures
- 32. Desktop Virtualization User Virtual desktop Virtualization layer Operating system Cloud Client office User desktop Delivered desktop by cloud Fig : Desktop Virtualization
- 33. Desktop Virtualization Desktop virtualization is a software technology that is used to separate the desktop and its connected application software from the physical device used by the client If there is any hardware or device failure then client can simply login from another device and components can be restored Virtualization breaks the connection between hardware and operating system, application Desktop virtualization benefits users by providing same desktop, which they can access from any device and from any where
- 34. Desktop Virtualization Desktop virtualization separates operating system, user configuration layers and applications It allows us to update and manage one layer without disturbing the other layers Techniques used in Desktop Virtualization - Remote Desktop Service (RDS) - Virtual Desktop Infrastructure (VDI)
- 35. Advantages of Desktop Virtualization creating new desktops is simple Installation of new application is cheaper Increased data security Protected reserved access to desktop to a business’ desktop settings Better business continuity and disaster recovery It is much easier to maintain virtual desktops than the physical PCs Users can work from home, outside the office or from any remote location Improved deployment and management
- 36. Disadvantages/Limitations of Desktop Virtualization Possible performance issue - hardware virtualization lowers functioning to some level Reliance on network connection - depends on network connection and it should have suitable bandwidth and low latency for good user experience Challenges in introducing and retaining drivers for peripherals Difficult to operate complicated applications Data of user not permanently deleted from network High percentage of physical memory is required by by virtual desktop, it depends on OS, workload, applications and other aspects
- 37. Disadvantages/Limitations of Desktop Virtualization Possible performance issue - hardware virtualization lowers functioning to some level Unsuitable for high-end graphic applications
- 38. Features of Desktop Virtualization Reduction in cost of desktops - It removes the need to have desktops or laptops for individual employees Reduction in management cost of desktop - Easy to manage desktops and their applications centrally or remotely which reduces the management cost Easy setting of desktops - Settings of desktops becomes very easy through centralized management console, the cost of move-add-change is also reduced Reduced cost to refresh desktops - It is easy for any organization to move from one operating system to another without any expense. It is also easy to extend desktop life cycle and management
- 39. Application Virtualization Virtualization Layer Cloud Application running Application delivered (Virtualized deliver ) User Client office Fig : Application Virtualization
- 40. Application Virtualization Application virtualization combines OS resources and separates them within virtualized container, which also contains the application that access the OS This technology allows any to install any application without making any changes to the file system, underlying OS or registry of the computer system Application virtualization includes separating the physical resources from the administration of the application Application encapsulation groups (packages) the application in a self contained executable package that does not depend on software installation or underlying OS These application packages are stored on centralized server
- 41. Application Virtualization These applications can run as standalone executables, they do not need to be mounted (installed) on the customer machine locally where they work Technologies used in application virtualization are - 1) Streaming of application 2) VDI or desktop virtualization 1) Streaming of application - Before startup, instead of transferring whole application, portion of application’s code, setting and data are delivered according to the requirement 2) VDI or desktop virtualization - The application is introduced in blade PC or VM which also include OS. VDI may normally fill up the gaps whenever applications’ streaming fails
- 42. Advantages of Application Virtualization Improved workload management Reduced hardware cost Increased flexibility for working remotely Simplified application deployment - Applications are never installed on operating system and removal of all application data from PC is assured Elimination of resource conflicts - Since each application has its own virtual OS resources, resource and application conflict are eliminated
- 43. Limitations/Disadvantages of Application Virtualization All software cannot be virtualized - For example applications that require a device driver or 16-bit application shared memory space cannot be virtualized Software such as anti-virus packages and applications that require heavy OS integration cannot be virtualized Tools used for Application Virtualization - 1) Microsoft Application Virtualization (App-V) 2) VMware ThinApp
- 44. Storage Virtualization Storage virtualization means grouping (pooling) various physical storage devices and presenting them as single virtual storage device Many times storage virtualization is also called as cloud storage With help of many management software, distributed storage groups including multiple storage units work as a single storage unit Storage virtualization can easily implemented using application software Functions such as physical storage, RAID, logical unit numbers (LUNs), LUN subdivisions, storage zones, logical volumes can be easily applied in various storages Storage virtualization creates an abstraction layer between the operating system and physical disks
- 45. Storage Virtualization With the help of storage virtualization tools, physical devices can be made available to various cloud users as logical devices Cloud users do not know if they are using physical storage or virtual storage The model of storage virtualization can be divided into four main layers - 1) storage devices 2) block aggregation layer 3) file layer 4) application layer
- 46. Storage Virtualization Advantages of Storage Virtualization - - Change the data access as required - Easy and single interface is used for administering the storage - Data duplication and backup becomes easy - Efficiency of storage management is increased - Downtime (un-utilized) time is reduced
- 47. Virtual Machine Life Cycle IT Service Request Infrastructure requirement analysis IT Request Release VMs End of service Compute resources deallocated to other VMs VM Provision Load OS + Appliances Customize and configure Start the server VMs in Operation Serving web requests Migration services Scale on demand compute resources Fig : Virtual Machine Life Cycle
- 48. Virtual Machine(VM) Migration 1) IT Service Requests Virtual Machine (VM) life cycle starts by request to IT department for creating a new server for a particular service This request is being processed by the IT administration to start seeing the servers’ resource pool Matching these resources with the requirements, and starting the provision of the needed virtual machine. Once it is provisioned and started, it is ready to provide the required service according to an SLA (Service level agreement 2) Virtual Machine Provisioning Firstly, you need to select a server from a pool of available servers along with the appropriate OS template you need to provision the virtual machine.
- 49. Virtual Machine(VM) Migration 2) Virtual Machine Provisioning Secondly, you need to load the appropriate software (operating system you selected in the previous step, device drivers, middleware, and the needed applications for the service required). Thirdly, you need to customize and configure the machine (e.g., IP address, Gateway) to configure an associated network and storage resources. Finally, the virtual server is ready to start with its newly loaded software These tasks are done by IT or data center’s specialist 3) VMs in Operation After VM provisioning the VMs executes and and provide services to web requests. There are various VM migration services like - live migration, stop and copy- based migration. If particular VM is using more resources than it share then that VM should be shifted to other machine or given more resources
- 50. Virtual Machine(VM) Migration 3) VMs in Operation In order to achieve on demand computing resources, there should be an integration between virtualization’s management tools and SLA’s management tools to achieve balance in resources by migrating and monitoring the workloads 4) Release VMs After the VM has completed the requests it is called as the end of service All the compute resources allocated to the VM are deallocated and freed
- 51. Virtual Machine(VM) Migration The word migration means shifting from one place to another VM migration means to move application along with the implementation settings from one physical machine to another VM migration is required for server consolidation (power saving), resource scheduling and load balancing Techniques of VM migration - 1) Live migration a) Post-copy-based migration b) Pre-copy-based migration 2) Stop and copy-based migration
- 52. Live VM Migration In live migration virtual machine is migrated (moved) without any disruption while implementing its application VM migration is an important way for running applications and resources in big virtualized systems It allows dynamic handling of resources Applications can be dynamically shuffled to develop consistency and performance Techniques of live VM migration - a) Post-copy-based migration b) Pre-copy based migration
- 53. Live VM Migration (Post-copy-based) In this technique, the VM machine stops working on the source machine and only its implementation state (CPU, register, memory pages) are passed on to the destination machine After this the VM starts working on the destination machine All memory pages are not transferred from source to destination machine When VM requires a memory page, it creates a page fault and that required page is transmitted from source target machine When each memory page is shifted to the target machine , the VM begins on target machine
- 54. Live VM Migration (Post-copy-based) Steps in post-copy technique are as follow - 1) The VM is present on source machine 2) Execution state of machine is transferred before memory is transferred and if page fault is generated then the requested page is transferred 3) The VM is activated on the target machine
- 55. Live VM Migration (Pre-copy-based) In this technique the VM memory is copied from source machine to destination machine while it continues to run on the source It repeatedly copies dirty pages until a stopping condition is met, at that time VM is temporarily paused After VM is temporarily charged, the final and remaining dirty pages copied and the VM resume its execution on the destination machine Temporary pages are those pages which are modified (changed) during copying process Steps in pre-copy technique are as follow - 1) Iterative (repeatedly) copying of memory 2) Stopping condition and final copy 3 VM activation on destination
- 56. Stop and Copy-based Migration It is a non-live migration method Virtual machine totally stops working on source machine All the memory pages are copied on the target machine after that VM executes on the target machine VM does not begin on target machine until all the pages are transmitted on the target machine It is a very simple and reliable technique Its disadvantage is that its downtime is high, VM does not begin till all pages are trasferred
- 57. Virtual Machine Management The various features of virtual machine management are as below - Creation - We can create a new virtual machine based on specific requirements, such as size, memory, and operating system Configuration (Settings) - Virtual machines can be configured to meet the needs of different applications. This includes adjusting resources like CPU and memory Monitoring - In this we monitor the performance of virtual machines and take necessary steps to optimize the performance of virtual machines Backup and Recovery - Data backup should be taken from VMs to prevent loss of data. In case of a failure, you can quickly restore the virtual machine to a previous state
- 58. Virtual Machine Management Security and Access control - Managing user permissions and securing VMs from unauthorized access Terminating VMs - Deleting virtual machines when they are no longer required and freeing up all resources allocated to them
- 59. Virtual Machine Consolidation Virtual Machine Consolidation reduces power utilization It also reduces operational charges for data center management On the basis of load conditions, under-used (less loaded) machines having resources below a limit and overloaded (high loaded) machines having resources over a certain limit are identified After that migration (shifting) is started to compactly place VMs to increase resource handling on all physical machines (PMs) and relieve resources of PMs, if possible PMs having resource handling values above upper limit are decided to have produced hotspots and PMs having resources handling values less than the lower limit are said to have created cold spots
- 60. Virtual Machine Consolidation Hotspots means over-consumption (higher consumption) of resources and coldspots means under-consumption (lower consumption) of resources Live migration may be used to equally distribute resources among clients The total system load may can be balanced by moving VMs from overloaded PMs to under loaded PMs
- 61. Technology Examples - VMWare User modified (unmodified ABI) Guest operating system unmodified codebase VMM unaware Hypervisor Binary translation Instruction caching Hardware x86 architecture Dynamic / cache translation Hardware traps Ring 0 Ring 1 Ring 2 Ring 3 FIg : VMWare Full Virtualization reference model
- 62. Technology Examples - VMWare VMware's full virtualization model replicates the underlying hardware for guest operating systems, allowing them to run unmodified on top of a hypervisor The technology of VMWare is based on concept of Full Virtualization Full virtualization means the guest operating system (OS) is unaware of the virtualization layer and doesn't require modification to run. VMware achieves this by creating a virtualized environment that closely mimics (looks like) the underlying physical hardware. VMWare implements full virtualization with the help of type-II hypervisor (in desktop environment) or type-1 (in server environemnt)
- 63. Technology Examples - VMWare In both cases, full virtualization is possible through the direct execution of non-sensitive instructions and binary translation for sensitive instructions or hardware traps VMware is widely used as it tends to virtualize x86 architectures When virtual machine (VM) wants to execute instructions then VMWare can do it in two ways - 1) direct execution 2) binary translation Direct Execution - For many simple instructions, the VM runs them directly on the hardware. This is efficient and fast Binary Translation - For more complex or sensitive instructions that could affect the system's stability or security, VMware translates these instructions into something the hardware can understand. This translation happens at runtime, meaning while the program is running.
- 64. Technology Examples - VMWare Some sensitive instructions can’t be run directly because they would normally require special privileges (like running in “Ring 0,” which is the highest level of access). Instead, when a sensitive instruction is called, it creates a “trap,” which is like a signal that something special needs to happen. VMware then translates this instruction to ensure it works properly in the virtual environment Guest operating system runs in ‘Ring 1’ It uses a code cache to saved the translated most used instructions to enhance the performance
- 65. Technology Examples - VMWare Disdvantages of Binary Translation - It takes a more time at run time - The performance of full virtualization on the x86 architecture is 80 to 95 percent that of the host machine. - Lage performance overhead - Code cache increases memory utilization along with hardware cost Advantages of Binary Translation - This kind of virtualization achieves best isolation (separation) and security of VM - Many isolated guest OS can execute concurrently (at a same time ) on same hardware - Hardware assist or operating system assist (help) is not require for virtualization of sensitive and privilege instructions
- 66. Technology Examples - Xen User modified (unmodified ABI) User domains Guest OS modified codebase, hypercalls into Xen VMM Xen Hypervisor (VMM) Memory management CPU state register Devices I/O Hardware x86 architecture Hardware traps Ring 0 Ring 1 Ring 2 Ring 3 Fig : Xen architecture and OS Mangement Privileged instructions Management domain VM Management HTTP Interface Access to Xen Hypervisor
- 67. Technology Examples - Xen Xen is an open source hypervisor and uses paravirtualization, it directly runs on hardware and manages all resources In paravirtualization, the guest operating system is aware of virtualization and Instead of directly accessing hardware, they make calls to the hypervisor (hypercalls) for privileged operations like memory management and I/O Xen manages the execution of multiple guest operating systems (guests or domains) by providing them with virtualized hardware resources (CPU, memory, etc.). The hypervisor runs in a highly privileged mode (Ring 0) while guest OSes run in a less privileged mode (Ring 1). This separation enhances security and control over resources.
- 68. Technology Examples - Xen A particular control software, which has privileged access to the host and handles all other guest OS, runs in a special domain called Domain 0 This software is loaded once the virtual machine manager has fully booted, and hosts an HTTP server that delivers requests for virtual machine creation, configuration, and termination This software also establishes the primary version of a shared virtual machine manager (VMM), which is a necessary part of Cloud computing system providing IaaS solutions Various implementations of Xen has four security levels called as rings - Ring 0, Ring 1, Ring 2, Ring 3 Ring 0 represents the level having highest privilege and Ring 3 represents the level having lowest privilege
- 69. Technology Examples - Xen Almost all the frequently used Operating system, uses only two levels i.e. Ring 0 for the Kernel code and Ring 3 for user application and non-privilege OS program Due to the structure of x86 instruction set, some instructions allow code execution in Ring 3 to switch to Ring 0 (Kernel mode)
- 70. Guest OS Management in Xen Hypercalls - Guests interact with the hypervisor through hypercalls, which are specific instructions that invoke Xen's functionality. This allows for efficient and controlled access to hardware resources Resource allocation - Xen allocates resources like CPU time, memory, and network interfaces to each guest, ensuring fair and efficient utilization of the underlying hardware I/O Virtualization - Xen uses shared rings and other mechanisms to facilitate I/O operations between guests and the hypervisor, minimizing overhead Virtual Networks - Xen provides virtual network interfaces (VIFs) to guests, allowing them to communicate with each other and the outside world through the hypervisor's networking stack
- 71. Guest OS Management in Xen Scheduling - Xen implements scheduling algorithms to determine which guest OS gets access to the CPU at any given time, ensuring a balance between performance and fairness. Security - Xen's paravirtualization approach enhances security by providing isolation between guests and preventing one guest from interfering with another's operations.
- 72. Technology Examples - Xen Advantages of Xen - Xen develops lighter and flexible hypervisor that provides their functionalities in an optimized manner - Xen supports balancing of large workload efficiently like workload of CPU,memory, disk I/O and network I/O - It also supports multiple processor, Iive migration one machine to another Disdvantages of Xen - Xen is less reliable on windows than linux OS - Xen relies on 3rd-party component to manage the resources like drivers, storage, backup, recovery & fault tolerance - Xen sometimes may cause increase in load on your resources and less resources for other VMs