Characteristics of virtualized environment Virtualization reference model

1. Guest Characteristics of virtualized environmentVirtualization reference model Virtualization Layer Virtual Image Applications Physical Storage Applications Physical Networking Virtual Storage Virtual Hardware Virtual Networking Physical Hardware Software Emulation Host

2. Increased security • Managed Execution A)Sharing B) Aggregation C)Emulation D)Isolation • Portability

3. Taxonomoy of Virtualized Environment How it is done? Technique Virtualization Model Emulation Application Network Execution Environment Storage Process Level High-Level VM Programming Language Multiprogramming Operating System Virtualization Hardware-assisted Virtualization Full Virtualization System Level Hardware Paravirtualization …. Partial Virtualization

4. Execution virtualization1)Machine reference model Applications Applications API calls API Libraries Libraries User ISA ABI System calls User ISA Operative System Operative System ISA ISA Hardware Hardware

5. 2 Hardware Level virtualization Guest In memory representation Virtual Image Storage VMM Host emulation Virtual Machine binary translation instruction mapping interpretation …… Host

7. 3)Hardware Virtualization techniques • Hardware assisted virtualization • Full virtualization • Para virtualization • Partial virtualization

8. Hypervisors

9. 4) OS level virtualization offers the opportunity to create different and separated execution environments for applications that are managed concurrently. It is different from hardware virtualization —there is no virtual machine manager or hypervisor, and the virtualization is done within a single operating system, where the OS kernel allows for multiple isolated user space instances.

10. 5)Programming level virtualization is mostly used for achieving ease of deployment of applications, managed execution, and portability across different platforms and operating systems. It consists of a virtual machine executing the byte code of a program, which is the result of the compilation process.

11. 6)Application level virtualization Interpretation Binary Translation

12. Virtualization and cloud Server B (running) Server B (inactive) Server A (running) Server A (running) VM VM VM VM VM VM VM VM VM VM VM VM Virtual Machine Manager Virtual Machine Manager Before Migration After Migration

13. Advantage and disadvantage of virtualization • Advantages: • Eliminates the need for numerous dedicated servers; • Offers the ability for different domain names, file directories, email administration, IP addresses, logs and analytics; • Cost effective because many times server software installation provisioning is available; • If one virtual server has a software failure, the other servers will not be affected; • Reduces energy costs because only one device is running instead of several; • Offers a flexibe IT infrastructure; • Can quickly make changes with little downtime.

14. Disadvantages • Resource hogging could occur if there are too many virtual servers within a physical machine; • As software updates and patches must be compatible with everything running on the virtual machine, admins may have reduced control over the physical environment; • Administration, including backup and recovery, requires specialized knowledge; • If user experience is impacted, it can be difficult to identify the root cause; • Services offered by a dedicated server are more accessible.