chapitre 4-Understanding Virtualization in the Cloud.pptx

Virtualization

1. Chapter 4 Understanding Virtualization in the Cloud Manel Medhioub [email protected] 4 ArcTIC Esprit 2020-2021 Initiation au Cloud

2. Introduction 2

3. Introduction 3

4. Introduction Physical and virtual servers co-exist Virtual servers managed as virtual resource pools 4

5. Lesson plan 5 2- Virtualization in Cloud 1- Virtualization definition 4 - Virtualization concerns 3- key capabilities

6. Virtualization definition The simulation of the software and/or hardware upon which other software runs. NIST SP 800-125 The use of an abstraction layer to simulate computing hardware so that multiple operating systems can run on a single computer. NIST SP 800-44 Version 2 Virtualization is the process of creating a software-based, or virtual, representation of something, such as virtual applications, servers, storage and networks. Vmware 6

7. Virtualization definition Virtualization simulates the interface to a physical object by any one of four means: Multiplexing : Create multiple virtual objects from one instance of a physical object. Example: a processor is multiplexed among a number of processes or threads. Aggregation :  Create one virtual object from multiple physical objects. Example: a number of physical disks are aggregated into a RAID disk. Emulation:  Construct a virtual object from a different type of physical object. Example, a physical disk emulates a random access memory. Multiplexing and emulation:   Examples : Virtual memory with paging multiplexes real memory and disk, and a Virtual address emulates a real address; TCP emulates a reliable bit pipe and multiplexes a physical communication channel and a processor. Dan C. Marinescu , "Cloud Computing: Theory and Practice" 7

8. Virtualization definition 8 Simplify the administration of resources Enhanced Security Fewer servers Optimizing Performance Stability and reliability Simplify the deployment of virtual machines Reduced costs Power and space reduction

9. Virtualization definition Many administrative tasks can be performed more easily using virtual servers as opposed to using their physical counterparts Virtualized IT resource management is often supported by virtualization infrastructure management (VIM) tools several advanced management functions can automate administration tasks and reduce the overall operational burden on virtualized IT resources. 9

10. Virtualization in Cloud Virtualization is a foundational element of cloud computing and helps deliver on the value of cloud computing Virtualization is transforming the face of the modern data center, it offers consolidation and improved IT operational efficiency. Virtualization technologies enable multi-tenancy cloud business models by providing a scalable, shared resource platform for all tenants. 10

11. Virtualization in Cloud 11 Physical Storage Computing Hardware Operating Systems Data Sources Applications Services Storage Grid (NAS, SAN) Hypervisor (VMware, Xen) Virtual Machine Data Grid Utility Computing (Apache Tomcat, JBoss , Oracle App Server) Software as a Service Virtualization layers

12. Virtualization in Cloud The different types of virtualization that are characteristic of cloud computing: Access: A client can request access to a cloud service from any location. Application: A cloud has multiple application instances and directs requests to an instance based on conditions. CPU: Computers can be partitioned into a set of virtual machines with each machine being assigned a workload (through load-balancing technologies) Storage: Data is stored across storage devices and often replicated for redundancy. 12

13. Virtualization in Cloud 13

14. Virtualization in Cloud Virtualization has four characteristics that make it ideal for CC: Partitioning:  you can use partitioning to support many applications and ( OSes ) in a single physical system. Isolation:  Because each virtual machine is isolated, each machine is protected from crashes and viruses in the other machines. What makes virtualization so important for the cloud is that it decouples the software from the hardware. Encapsulation:  Encapsulation can protect each application so that it doesn’t interfere with other applications. A virtual machine can be represented/stored as a single file, making it easy to identify and present to other applications. Hardware Independence: Provision or migrate any virtual machine to any physical server. 14

15. Virtualization in Cloud 15

16. Virtualization in Cloud Virtualization also provides several key capabilities for cloud computing, including s erver consolidation, resource pooling, isolation , load balancing, m igration. In a cloud environment, these capabilities enable scalability, high utilization of pooled resources, rapid provisioning, workload isolation, and increased uptime. 16

17. Key capabilities Server Consolidation Virtualization technology enables different virtual servers to share one physical server. multiple virtual servers are simultaneously created in the same virtualization host different virtual servers can run different guest operating systems on the same host This process is called server consolidation and is commonly used to increase hardware utilization, load balancing, and optimization of available IT resources. 17

18. Key capabilities Server Consolidation This fundamental capability directly supports common cloud features, such as on-demand usage, resource pooling, elasticity, and resiliency. Virtualization makes it possible to scale up computing resources on-demand. This allows forms to add new computing resources just when they need it, and manage costs. 18

19. Key capabilities Resource pooling Grouping or creation of resource pool It differentiates cloud computing from all other types of networked systems. Without resource pooling, it is impossible to Attain efficient utilization Provide reasonable costs to users Proactively react to demand 19

20. Key capabilities Resource pooling Virtualization allow the access to pooled resources, it : assigns a logical name for a physical resource provides a pointer to that physical resource when a request is made. Virtualization provides a means to manage resources efficiently: the mapping of virtual resources to physical resources can be both dynamic and facile. 20

21. Key capabilities Resource pooling The key to creating a pool is to provide an abstraction mechanism Cloud computing use a set of techniques that abstract physical resources such as processors, memory, disk, and network capacity into virtual resources. Abstraction enables the key benefit of cloud computing: shared, ubiquitous access. 21

22. Key capabilities Resource pooling The abstraction layer provides a unified view of distributed and heterogeneous physical resources generally by mean of virtualization. 22

23. Key capabilities Resource pooling Infrastructure as a service is built on pooled resources for computing, storage, and networking 23

24. Key capabilities Load Balancing The technology used to distribute service requests to resources is referred to as load balancing. Load balancing is an optimization technique used to: reduce response time lower latency increase utilization and throughput, avoid system overload. The load balancer mechanisms can exist as a: multi-layer network switch dedicated hardware appliance dedicated software-based system ( common in server operating systems ) service agent ( usually controlled by cloud management software ) 24

25. Key capabilities Load Balancing Load balancing provides to the Cloud The necessary redundancy to make an unreliable system reliable through managed redirection. Fault tolerance when coupled with a failover mechanism The load balancer uses a scheduling algorithm to assign where the request is sent: round robin weighted round robin fastest response time least connections and weighted least connections custom assignments based on other factors 25

26. Key capabilities Load Balancing Beyond simple division of labor algorithms, load balancers can perform a range of specialized runtime workload distribution functions that include: Asymmetric Distribution – larger workloads are issued to IT resources with higher processing capacities Workload Prioritization – workloads are scheduled, queued, discarded, and distributed workloads according to their priority levels Content-Aware Distribution – requests are distributed to different IT resources as dictated by the request content 26

27. Key capabilities Isolation The virtualization provide a level of isolation nearly equivalent to the isolation presented by two different physical systems Isolation among users: one user should be isolated from the other users so that he/she may not get information about the others user’s data and usage and cannot even access other’s data. 27

28. Key capabilities Isolation Workload Isolation Reliability enhancement : A fault in one module that might generate a system failure in one VM does not affect others VM running on the same physical block. Security enhancement : as compromise to security is limited to a specific compartment. Fault tolerance : as virtualization allows control over the state of VM through suspend, resume, mark a checkpoint, and roll back. 28

29. Key capabilities Isolation Security isolation: A VMM is a much simpler and better specified system than a traditional operating system The security vulnerability of VMMs is considerably reduced as the systems expose a much smaller number of privileged functions 29

30. Key capabilities Migration Through hardware independence, virtual servers can easily be moved to another virtualization host, automatically resolving multiple hardware-software incompatibility issues. As a result, cloning and manipulating virtual IT resources is much easier than duplicating physical hardware. 30

31. Key capabilities Migration Virtualization supports system migration, It allows hot migrations  plays an important role for performance and reliability, as it allows applications to migrate from one platform to another balance workloads based on performance requirements. Workload migration automation must be established based on full transparency of the dynamic cloud environment.  31

32. Key capabilities Migration Live migration is the movement of a virtual machine from one physical host to another while continuously powered-up. When properly carried out, this process takes place without any noticeable effect from the point of view of the end user. Live migration is a widely used technology for load-balancing, fault tolerance, and power saving in cloud datacenters. 32

33. Key capabilities Migration vMotion , part of vSphere, enables you to migrate virtual machines from one physical server to another with zero downtime, continuous service availability and complete transaction integrity. Live virtual machine migration allows you to perform hardware maintenance without scheduling downtime or disrupting business operations. 33

34. Key capabilities Migration 34 The VIM determines that scaling up the virtual server on Physical Server 1 is not possible and proceeds to live migrate it to Physical Server 2.

35. Virtualization concerns Many hardware vendors that distribute specialized hardware may not have device driver versions that are compatible with virtualization software. A poorly formulated virtualization plan can result in excessive performance overhead 35

36. Virtualization concerns Performance isolation is a critical condition for Quality of Service ( QoS ) guarantees in shared computing environments. Performance of resources remotely rented in virtualized form under precise service-level agreements  should be as stable and predictable as possible. 36

37. Virtualization concerns Multiple VMs are running on the same physical host and sharing a set of physical resources Traditional OS multiplex multiple processes Virtualisation supported by a VMM multiplexes full OS Obviously, there is a performance penalty as an OS is considerably more heavyweight than a process and the overhead of context switching is larger Use of various critical levels of scheduling: CPU scheduling, network scheduling and disk scheduling. 37

38. Virtualization concerns In the virtualized environment, the network is no longer physical Its configuration can actually change dynamically, which makes network monitoring difficult.  Software products ( available from companies such as VMWare , IBM ….) that can monitor virtual networks and, ultimately, dynamic virtual networks are required 38