ppt
TRANSCRIPT
What is hardware virtualization?
Indirect the underlying hardware layer
Allow multiplexing and isolation
Key points: Treat OS as a component Split the administrative role in half
What is Xen?
Virtual machine manager (VMM) Developed at University of
Cambridge An Isolation Kernel Recently included in mainline Linux Used in many production
environments
Virtualization in the Enterprise
X
Consolidate under-utilized servers to reduce CapEx and OpEx
Avoid downtime with VM Relocation
Dynamically re-balance workload to guarantee application SLAs
X Enforce security policyX
Why Xen is interesting for Grid/E-Science Environments
EncapsulationOS as management primitive, and strong isolation
AccountingCollect detailed usage data on each VM
Pre-emption and CheckpointingUsing suspend/resume
Load BalancingUsing migration
Storage virtualizationSimple virtual block interface can be mapped to whatever you like (disk/file/etc…)
Virtualization Overview
Single OS image: Virtuozo, Vservers, Zones Group user processes into resource containers Hard to get strong isolation
Full virtualization: VMware, VirtualPC, QEMU Run multiple unmodified guest OSes Hard to efficiently virtualize x86
Para-virtualization: UML, Xen Run multiple guest OSes ported to special arch Arch Xen/x86 is very close to normal x86
Paravirtualization
Virtualization is traditionally slow relative to raw hardware (IBM VM, VMware, etc)
Xen paravirtualizes Co-design with VM OS Optimize OS to run in a virtualized
environment Maintain ABI – applications stay the
same.
Xen 3.0 Architecture
Event Channel Virtual MMUVirtual CPU Control IF
Hardware (SMP, MMU, physical memory, Ethernet, SCSI/IDE)
NativeDeviceDriver
GuestOS(XenLinux)
Device Manager & Control s/w
VM0
NativeDeviceDriver
GuestOS(XenLinux)
UnmodifiedUser
Software
VM1
Front-EndDevice Drivers
GuestOS(XenLinux)
UnmodifiedUser
Software
VM2
Front-EndDevice Drivers
UnmodifiedGuestOS(WinXP))
UnmodifiedUser
Software
VM3
Safe HW IF
Xen Virtual Machine Monitor
Back-End Back-End
VT-x
32/64bit
AGPACPIPCI
SMP
System Performance
L X V U
SPEC INT2000 (score)
L X V U
Linux build time (s)
L X V U
OSDB-OLTP (tup/s)
L X V U
SPEC WEB99 (score)
0.0
0.1
0.2
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0.8
0.9
1.0
1.1
Benchmark suite running on Linux (L), Xen (X), VMware Workstation (V), and UML (U)
TCP results
L X V UTx, MTU 1500 (Mbps)
L X V URx, MTU 1500 (Mbps)
L X V UTx, MTU 500 (Mbps)
L X V URx, MTU 500 (Mbps)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
TCP bandwidth on Linux (L), Xen (X), VMWare Workstation (V), and UML (U)
Scalability
L X
2L X
4L X
8L X
16
0
200
400
600
800
1000
Simultaneous SPEC WEB99 Instances on Linux (L) and Xen(X)
Web Server Relocation
Performance issues for GRID environments
One problematic workload: Synchronous, low-latency, MPI-style communications. Domain crossings / no batching.
BUT: Hardware vendors know this is a problem that needs fixing. Several vendors are in the process of
building virtualization-friendly devices.
Existing GRID Users
Tim Freeman and Kate Keahey at Argonne National Lab in Chicago
Looking at combining virtualization with GRID Environment creation, management,
etc.
Other Xen Supporters
Hardware Systems
Platforms & I/O
Operating System and Systems Management
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Ongoing Work
Parallax: Distributed VM storage Decentralized, data replication, copy-on-
write Pervasive Debugging
VMs are an ideal debugging environment
XenSE: Security Enhanced Xen MAC-based VMM
Conclusions
Xen is a complete and robust GPL VMM Outstanding performance and scalability Excellent resource control and protection Live relocation makes seamless migration
possible for many real-time workloads
http://www.cl.cam.ac.uk/Research/SRG/netos/xen/(Google for “Xen”)