Anna University-CCS335

1. DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING
UNIT-2
OS LEVEL VIRTUALIZATION
MIDDLEWARE SUPPORT FOR VIRTUALIZATION
Dr.A.SOLAIRAJ, Associate Professor , Department of CSE, NSCET, THENI
NADAR SARASWATHI COLLEGE OF ENGINEERING AND TECHNOLOGY,THENI

2. UNIT-2
Virtual Machines and Virtualization of Clusters and Data Centers
2.1 Implementation Levels of Virtualization
2.1.1 Levels of Virtualization Implementation
2.1.2 VMM Design Requirements and Providers
2.1.3 Virtualization Support at the OS Level
2.1.4 Middleware Support for Virtualization
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

3. DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING
WITH VIRTUAL MACHINE Vs WITHOUT VIRTUAL MACHINE

4. DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

5. VIRTUALIZATION TYPES
Full virtualization vs para virtualization vs OS level virtualization
There are three ways to create virtual servers: Full virtualization, Para-virtualization and OS-level virtualization
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

6. DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

7. FULL VIRUALIZATION
Full virtualization:
 Guest operating systems are unaware of each other
 Provide support for unmodified guest operating system.
 Hypervisor directly interact with the hardware such as CPU, disks.
 Hyperwiser allow to run multiple os simultaneously on host computer.
 Each guest server run on its own operating system
 Few implementations: Oracle's Virtaulbox , VMware server, Microsoft Virtual PC
Advantages:
 This type of virtualization provide best isolation and security for Virtual machine.
 Truly isolated multiple guest os can run simultaneously on same hardware.
 It's only option that requires no hardware assist or os assist to virtualize sensitive and privileged
instructions.
Limitations:
 1.full virtualization is usually bit slower ,because of all emulation.
 2.hyoerwiser contain the device driver and it might be difficult for new device drivers to be
installer by users.
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

8. PARA VIRTUALIZATION
Para virtualization:
 unlike full virtualization ,guest servers are aware of one another.
 Hypervisor does not need large amounts of processing power to manage guest os.
 The entire system work as a cohesive unit.
Advantages:
 As a guest os can directly communicate with hypervisor
 This is efficient virtualization.
 Allow users to make use of new or modified device drivers.
Limitations:
 Para virtualization requires the guest os to be modified in order to interact with para virtualization
interfaces.
 It requires significant support and maintaibilty issues in production environment.
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

9. 2.1.3.Virtualization Support at the OS Level
 Cloud computing is transforming the computing landscape by shifting
the hardware and staffing costs of managing a computational center to
third parties, just like banks.
 The first is the ability to use a variable number of physical machines and
VM instances depending on the needs of a problem
 For example, a task may need only a single CPU during some phases of
execution but may need hundreds of CPUs at other times
 The second challenge concerns the slow operation of instantiating new
VMs
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

10.  In a cloud computing environment, perhaps thousands of VMs
need to be initialized simultaneously.
 Moreover, full virtualization at the hardware level also has the
disadvantages of slow performance and low density, and the need
for para-virtualization to modify the guest OS.
 To reduce the performance overhead of hardware-level
virtualization, even hardware modification is needed.
 OS-level virtualization provides a feasible solution for these
hardware-level virtualization issues.
Why OS Level Virtualization?
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

11.  Operating system virtualization inserts a virtualization layer inside an
operating system to partition a machine’s physical resources.
 It enables multiple isolated VMs within a single operating system kernel.
This kind of VM is often called a virtual execution environment (VE).
 From the user’s point of view, VEs look like real servers. This means a VE
has its own set of processes, file system, user accounts, network
interfaces with IP addresses, routing tables, firewall rules, and other
personal settings
Why OS Level Virtualization?
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

12. Advantages of OS Extensions
 All OS-level VMs on the same physical machine share a single
operating system kernel
 The virtualization layer can be designed in a way that allows
processes in VMs to access as many resources of the host
machine as possible, but never to modify them
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

13. Disadvantages of OS Extensions
 The main disadvantage of OS extensions is that all the VMs at
operating system level on a single container must have the same
kind of guest operating system.
 For example, a Windows distribution such as Windows XP
cannot run on a Linux-based container. However, users of cloud
computing have various preferences. Some prefer Windows and
others prefer Linux or other operating systems. Therefore, there
is a challenge for OS-level virtualization in such cases.
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

14. Virtualization on Linux or Windows Platforms
 OS-level virtualization systems are Linux-based. Virtualization
support on the Windows-based platform is still in the research
stage.
 Two OS tools (Linux vServer and OpenVZ) support Linux
platforms to run other platform-based applications through
virtualization.
 The third tool, FVM, is an attempt specifically developed for
virtualization on the Windows NT platform.
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

15. Virtualization Support for the Linux Platform
 OpenVZ is an OS-level tool designed to support Linux platforms
to create virtual environments for running VMs under different
guest OS.
 OpenVZ is an open source container-based virtualization
solution built on Linux.
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING

16. 2.1.4.Middleware Support for Virtualization
 Library-level virtualization is also known as user-level
Application Binary Interface (ABI) or API emulation.
 Library-level virtualization is also known as user-level
Application Binary Interface (ABI) or API emulation
 This type of virtualization can create execution environments for
running programs on a platform rather than creating a VM to
run the entire operating system.
DEPARTMENT OF COMPUTER SCIENCE AND ENGINEERING