WIXLIB

PAC097VMware Workstation andGSX Server Architecture andInternals: The EvolutionScott DevineFounder, Principal EngineerVMware

This presentation may contain VMwareconfidential information.Copyright 2005 VMware, Inc. All rights reserved. All othermarks and names mentioned herein may be trademarks of their respectivecompanies.

Outline Basic Architecture Virtual Machine State Networking

Conventional Computer SystemApplicationApplicationApplicationOperating SystemHardware Operating Systems provide Hardware management / device drivers Application programmers interface (APIs)

Traditional Virtual Machine nOperating SystemOperating SystemVirtual MachineVirtual MachineVirtual Machine MonitorHardware Virtual machines provide Encapsulation Isolation Hardware Independence

VMware Workstation Goals Provide the traditional benefits ofvirtual machines Virtualize x86 PCs Run like an application Run with good performance

VMware as an Application Installs like an application on anexisting computer system All virtual machine data stored onexisting file system No disk partitioning Native applications can runsimultaneously to virtual machines Use existing device drivers

VMware as an ApplicationAppAppGuest OSVirtual MachineNativeApplicationVMware WorkstationHost OSHardware

VMware Virtual Machine Monitor Virtualization techniques require Access to privileged CPU state Complete control of the Memory Management Unit(MMU) The Host OS gets in our wayNeed to both run as an application andas a privileged virtual machine monitor

3-Component ModelAppNativeApplicationAppGuest OSVMware WorkstationVirtual MachineVMMHost OSHardware Switch to privileged VMM to run virtualmachine VMM takes complete control of CPU and MMU Host OS state is saved / restored on “World” switch

Resources The application only switches to the VMMwhen it’s running VMM switches back on interrupts Host OS sees the application as running during thistime The application allocates all memory used bythe virtual machine All resources used by the virtual machineare charged to the application

DevicesAppNativeApplicationAppGuest OSVMware WorkstationVirtual MachineVMMHost OSHardware Device I/O is routed through theapplication Use standard OS system call interfaces

CPU / Memory Virtualization Traditional virtualization techniqueDirect Execution Run OS at an unprivileged CPU level CPU traps to VMM on privileged instructions VMM emulates privileged instruction However, x86 is not strictlyvirtualizable

Binary Translation Inspects each instruction before itsexecuted Replaces “dangerous” instructionswith calls to emulation code Stores sequences of translatedinstructions in a translation cache Fast, but slower than direct execution

Dual Virtualization Method Use traditional direct execution whenpossible Well behaved user-level programs Use binary translation when not Operating system Real mode programs (old 16 bit DOS apps) User-level programs with special privileges (Xserver on Linux)

Dual Virtualization MethodDirect ExecutionReturn toVMDirectExec.OK?Binary TranslationCPUStateEmulationPrivilegedInstruction

Goals Met 3-Component model Acts like an application Use raw hardware for best performance Device I/O through application Reuse device drivers on host OS Dual virtualization Virtual x86 with binary translation Get good performance with direct execution

Outline Basic Architecture Virtual Machine State Networking

Virtual Machine State Virtual machine encapsulation: All thestate of the virtual machine is stored ona few files on the host file system

Disks All disk state is stored inhost files Disk read/writecommands from theguest are translated intofile read/write systemcallsAppAppGuest OSVMDiskHostFile

Delta DisksBaseDiskVM ADiskDeltaDisk Only stores differences between original andchild Dependent on original disk not changing

Checkpoints Virtual machine’s runningstate captured to a hostfile CPU state Memory Device state TimeAppAppGuest OSVMCheckpointFile

Undoable Disks – Workstation 1.0VM’sDiskDiskFile Put disk in Undoable mode

Undoable Disks – Workstation 1.0VM’sDisk.REDODiskFile Put disk in Undoable mode All writes would go to a .REDO deltadisk

Undoable Disks – Workstation 1.0.REDOVM’sDiskDiskFile Put disk in Undoable mode All writes would go to a .REDO deltadisk Commit or discard at power off

Undoable Disks – Workstation 1.0.REDOVM’sDiskDiskFile Put disk in Undoable mode All writes would go to a .REDO deltadisk Commit or discard at power off

Suspend/Resume – Workstation 2.0 Use a checkpoint to suspend executionof virtual machine to disk All running state of the virtual machine issaved in checkpoint Disk state is already on in a file Resume will continue execution Checkpoint file is removed Can only resume from a suspend once

Snapshots – Workstation 4.0AppBaseDiskAppGuest OSVM “Undoableness” for the whole virtualmachine Take a snapshot at any point Revert to a snapshot many times

Snapshots – Workstation t OSVM Undoableness for the whole virtualmachine Take a snapshot at any point Revert to a snapshot many times

Multiple Snapshots –Workstation 5.0 Creates a timeline of snapshots Going back in time does not deletefuture snapshots Creates a tree of snapshots All snapshots are kept with the virtualmachine

Clones – Workstation 5.0BaseDiskVM ADiskDeltaDiskDeltaDiskVM BDisk Creates a copy of the virtual machine

Outline Basic Architecture Virtual Machine State Networking

Basic NetworkingAppAppAppAppGuest OSGuest OSVirtual MachineVirtual MachineNativeApplicationHost OSVmnet 1 Vmnets acts as virtual switches

Bridged – Workstation 1.0AppAppGuest OSVirtual MachineHostNetworkStackBridgeVmnet 0 Makes Vmnet look like an extension of the realEthernet

Host File Access – Workstation 2.0AppAppDHCPServerGuest OSVirtual MachineHostNetwork StackVmnet 1HostIf Extra setup on Linux to share host file system onnew network interface

NAT – Workstation 3.0AppNATProcessAppGuest OSVirtual MachineHostHostNetwork StackVmnet 8 NAT process does the address translation for allvirtual machines on Vmnet 8

Teams – Workstation 5.0AppAppAppAppAppAppGuest OSGuest OSGuest OSClient VMFirewall VMServer VMHostTeam PrivateVmnet ATeam PrivateVmnet B Team: A group of networked virtualmachines with the network topology

Team Network Properties Team Private Vmnets have knobs Bandwidth Packet Loss Rate Can simulate modems, DSL, T1, LANs

VMware GSX Server Goals Enhance the VMware virtualizationplatform for enterprise servers Remote management Scripting

Remote Management in uest OSVirtual MachineVMMHost OSHardware Web-based remote management Serverd manages all running virtualmachines

Remote st OSVirtual MachineVMMHost OSHardware Remote Console connections go direct tothe virtual machines

VirtualCenter Guest OSVirtual MachineVMMHost OSHardware GSX Server can be managed byVirutalCenter VirtualCenter connects direct to serverd

Conclusion Basic virtualization techniques have stoodthe test of time Extended I/O functionality Extended remote managementcapabilities

VMware GSX Server Goals Enhance the VMware virtualization platform for enterprise servers Remote management Scripting. Remote Management in GSX Server Web-based remote management Serverd manages all running virtual machines Hardware Host OS Virtual