Linux Foundation Collaboration Summit 13 :10 years of Xen and Beyond

Lars Kurth Xen Project Community Manager

[email protected]

10 Years of Xen and beyond …

@lars_kurth FREENODE: lars_kurth

• Teams aka sub-projects

– Hypervisor

– XAPI

– ARM Hypervisor (for Servers as well as Mobile Devices)

– Mirage OS

• Governance : mixture between Linux Kernel and Apache

– Consensus decision making

– Sub-project life-cycle (aka incubator)

– PMC style structure for team leadership

Xen.org becomes XenProject.org

Xen contributor community is diversifying

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

2010 2011 2012

Citrix UPC

SUSE Amazon

University AMD

GridCentric Individual

NSA Intel

Fujitsu iWeb

Misc Oracle

Spectralogic University of British Columbia

• The number of “significant” active vendors is increasing

• New feature development driving new participation

Hypervisor Architecture

Hypervisor Architectures Type 1: Bare metal Hypervisor

A pure Hypervisor that runs directly on the hardware and hosts Guest OS’s.

Provides partition isolation + reliability, higher security

Host HW Memory CPUs I/O

Hypervisor Scheduler

MMU Device Drivers/Models

VMn

VM1

VM0

Guest OS and Apps

Hypervisor Architectures Type 1: Bare metal Hypervisor

A pure Hypervisor that runs directly on the hardware and hosts Guest OS’s.

Type 2: OS ‘Hosted’

A Hypervisor that runs within a Host OS and hosts Guest OS’s inside of it, using the host OS services to provide the virtual environment.

Provides partition isolation + reliability, higher security

Low cost, no additional drivers Ease of use & installation





VMn

VM1

VM0

Guest OS and Apps

Host OS

Device Drivers Ring-0 VM Monitor “Kernel “

VMn

VM1

VM0

Guest OS and Apps

User Apps

User-level VMM

Device Models

Xen: Type 1 with a Twist Type 1: Bare metal Hypervisor




VMn

VM1

VM0

Guest OS and Apps





VMn

VM1

VM0

Guest OS and Apps


Hypervisor

VMn

VM1

VM0

Guest OS and Apps

Xen Architecture

Scheduler MMU





VMn

VM1

VM0

Guest OS and Apps


Hypervisor

VMn

VM1

VM0

Guest OS and Apps

Xen Architecture

Scheduler MMU

Control domain (dom0)

Drivers

Device Models

Linux & BSD

Xen Project and Linux

• Xen Hypervisor is not in the Linux kernel

• BUT: everything Xen and Xen Guests need to run is!

• Xen packages are in all Linux distros (except RHEL6) – Install Dom0 Linux distro

– Install Xen package(s) or meta package

– Reboot

– Config stuff: set up disks, peripherals, etc.

More info: wiki.xen.org/wiki/Category:Host_Install

Basic Xen Concepts

11


Host HW

VMn

VM1

VM0

Guest OS and Apps

Memory CPUs I/O

Console • Interface to the outside world

Control Domain aka Dom0 • Dom0 kernel with drivers • Xen Management Toolstack

Guest Domains • Your apps

Driver/Stub/Service Domain(s) • A “driver, device model or control

service in a box” • De-privileged and isolated • Lifetime: start, stop, kill

Dom0 Kernel

Hypervisor Scheduler MMU XSM

Trusted Computing Base

http://wiki.xen.org/xenwiki/XenDom0Kernels

Basic Xen Concepts

12


Host HW

VMn

VM1

VM0

Guest OS and Apps

Console

Memory CPUs I/O

Dom0 Kernel

Toolstack






service in a box” • De-privileged and isolated • Lifetime: start, stop, kill Trusted Computing Base


Basic Xen Concepts

13


Host HW

VMn

VM1

VM0

Guest OS and Apps

Console

Memory CPUs I/O

One or more driver, stub or service domains

Dom0 Kernel

Toolstack






service in a box” • De-privileged and isolated • Lifetime: start, stop, kill Trusted Computing Base


14

Xen Variants for Server & Cloud Xen Hypervisor Hypervisor

Single Host Basic Functions

Multiple Hosts Additional Functionality

15

Xen Variants for Server & Cloud

Increased level of functionality and integration with other components

Default / XL (XM) Toolstack / Console Libvirt / VIRSH XAPI / XE

Hypervisor

Single Host Additional Functionality

Xen Hypervisor






Hypervisor


Xen Hypervisor

17



Default / XL (XM) Toolstack / Console Libvirt / VIRSH

Products Oracle VM Huawei UVP Citrix XenServer

Project

XAPI / XE

Xen Hypervisor

18



Default / XL (XM) Toolstack / Console Libvirt / VIRSH

Used by …

Project

XAPI / XE

Products Oracle VM Huawei UVP Citrix XenServer

Xen Hypervisor

Xen : Types of Virtualization

20

Xen Hypervisor


Host HW

Guest VMn

Apps

Memory CPUs I/O

Technology:

• Paravirtualization

Linux PV guests have limitations:

• limited to a subset of set of virtual HW

Advantages • Fast • Works on any system

(even without virt extensions)

HW Drivers

PV Back Ends PV Front Ends

Guest OS Dom0 Kernel

PV Domains

21

Xen Hypervisor


Host HW

Guest VMn

Apps

Memory CPUs I/O

Technology:

• Paravirtualization

Linux PV guests have limitations:

• limited to a subset of virtual HW

Advantages • Fast • Works on any system

(even without virt extensions)

Driver Domains • Security • Isolation • Reliability and Robustness

HW Drivers

PV Back Ends PV Front Ends

Driver Domain e.g. • Disk • Network

HW Driver

PV Back End

Dom0 Kernel*

*) Can be MiniOS

Guest OS Dom0 Kernel

PV Domains & Driver Domains

22

Xen Hypervisor

Dom0

Host HW

Guest VMn

Technology:

• Shows emulation using QEMU/Device Model (SW Virtualization)

• In other situation HW can be used

Disadvantages

• Emulation slower than PV (mainly I/O devices)

Advantages • No kernel support needed

Device Model IO Emulation

IO Event

VMEXIT Dom0 Kernel

HVM & Stub Domains

Memory CPUs I/O

23

Xen Hypervisor

Dom0

Host HW

Guest VMn

Technology:

• Shows emulation using QEMU/Device Model (SW Virtualization)

• In other situation HW can be used

Disadvantages

• Emulation slower than PV (mainly I/O devices)

Advantages • No kernel support needed

Stub Domains • Security • Isolation • Reliability and Robustness

Device Model IO Emulation

IO Event

VMEXIT

Stubdomn

Device Model

Mini OS

Guest VMn

IO Emulation

IO Event

VMEXIT Dom0 Kernel

HVM & Stub Domains

Memory CPUs I/O

The Virtualization Spectrum

Fully Virtualized (FV) VS VS VS VH

FV with PV for disk & network P VS VS VH

PVHVM P P VS VH

PVH P P P VH

Fully Paravirtualized (PV) P P P P

VH Virtualized (HW)

P Paravirtualized

VS Virtualized (SW)

HVM mode/domain

PV mode/domain Xen 4.4




PVHVM P P VS VH

PVH P P P VH


Scope for improvement

Poor performance

Optimal performance

HVM mode/domain

Xen 4.4 PV mode/domain




PVHVM P P VS VH

PVH P P P VH



Poor performance

Optimal performance

HVM mode/domain

Xen 4.4 PV mode/domain

Important: Xen automatically picks the best option based on HW & OS capabilities and available drivers.

As a Xen user I chose a HVM or PV domain.

XAPI, XCP and XCP-XAPI



XAPI, XCP and XCP-XAPI : What is it?



Hypervisor


Xen Hypervisor

XAPI : What do I get?


XAPI / XE

Xen Hypervisor • VM lifecycle: live snapshots, checkpoint, migration

• Storage XenMotion: Migrate VMs between hosts or pools without shared storage (while the VM is running)

• Resource pools: flexible storage and networking

• Event tracking: progress, notification

• Upgrade and patching capabilities

• Real-time performance monitoring and alerting

• Templates for Windows and Linux guests

• Open vSwitch support built-in (default)

More info: wiki.xen.org/wiki/XCP_Release_Features

XAPI : two variants!


XAPI / XE

Xen Hypervisor

XCP ISO (at v1.6)

Xen 4.1.3 + XAPI CentOS 5.3 Kernel (v2.6.32.43) OVS 1.4.2

XCP-XAPI packages

Debian Wheezy Ubuntu 12.04 LTS

Others in progress …

XAPI : Orchestration and UIs


XAPI / XE

Xen Hypervisor

Challenges for FOSS hypervisors

“Security and QoS/Reliability are amongst the top 3 blockers for cloud adoption”

www.colt.net/cio-research

http://www.colt.net/cio-research



System characteristics cloud users care about: “Robustness, Performance, Scalability & Security” Results XCP User Survey 2012 – 90% of users quoted these as most important attributes

Split Control Domain into Driver, Stub and Service Domains

– See: ”Breaking up is hard to do” @ Xen Papers

– See: “Domain 0 Disaggregation for XCP and XenServer”

Used today by Qubes OS and Citrix XenClient XT

Prototypes for XAPI

Disaggregation

See qubes-os.org

Different windows run in different VMs

http://www.cs.ubc.ca/~andy/papers/xoar-sosp-final.pdf

http://xen.org/community/xenpapers.html

http://www.xen.org/xensummit/xs12na_talks/T2.html

http://www.xen.org/xensummit/xs12na_talks/T2.html

http://qubes-os.org/Home.html

More Security

Increased serviceability and flexibility

Better Robustness

Better Performance

Better Scalability

Benefits of Disaggregation

Ability to safely restart parts of the system (e.g. just 275ms outage from failed Ethernet driver)

Next: XAPI Architecture Diagram Before and After Disaggregation

CPU CPU RAM RAM NIC

(or SR-

IOV VF)

NIC (or SR-

IOV VF)

NIC (or SR-

IOV VF)

NIC (or SR-

IOV VF)

RAID

Xen

Dom0 Network

drivers

NFS/

iSCSI drivers

Qemu

xapi Local

storage drivers

NFS/

iSCSI drivers

Network

drivers

Qemu

eth eth eth eth scsi

User VM User VM

NB gntdev NB

NF BF NF BF

qemu qemu

xapi

vswitch

networkd

tapdisk

blktap3

storaged

syslogd vswitch

networkd

tapdisk

blktap3

storaged

tapdisk

blktap3

storaged

gntdev gntdev

Dom0

xenopsd

libxl

healthd

Domain

manager

Dom0

.

.

.

.

Xen

xapi

CPU CPU RAM RAM NIC

(or SR-

IOV VF)

NIC (or SR-

IOV VF)

NIC (or SR-

IOV VF)

NIC (or SR-

IOV VF)

RAID

Dom0 Network

driver

domain

NFS/

iSCSI driver

domain

Qemu

domain

xapi

domain

Logging

domain Local

storage driver

domain

NFS/

iSCSI driver

domain

Network

driver

domain

User VM User VM

NB gntdev NB

NF BF NF BF

dbus over v4v

qemu

xapi xenopsd

libxl

healthd

Domain

manager

vswitch

networkd

tapdisk

blktap3

storaged

syslogd vswitch

networkd

tapdisk

blktap3

storaged

tapdisk

blktap3

storaged

gntdev gntdev


Xen Xen

D

o

m

0

dbus over v4v

.

.

.

40

Xen Security Advantages

• Even without Advanced Security Features – Well-defined trusted computing base (much smaller than on type-2 HV)

– Minimal services in hypervisor layer

• Xen Security Modules (or XSM) and FLASK – XSM is Xen equivalent of LSM

– FLASK is Xen equivalent of SELinux

– Developed, maintained and contributed to Xen by NSA

– Compatible with SELinux (tools, architecture)

– XSM object classes maps onto Xen features

More info: http://www.slideshare.net/xen_com_mgr/ a-brief-tutorial-on-xens-advanced-security-features

http://selinuxproject.org/page/Main_Page

CPU CPU RAM RAM NIC

(or SR-

IOV VF)

NIC (or SR-

IOV VF)

NIC (or SR-

IOV VF)

NIC (or SR-

IOV VF)

RAID

Xen

Dom0 Network

driver

domain

NFS/

iSCSI driver

domain

Qemu

domain

xapi

domain

Logging

domain Local

storage driver

domain

NFS/

iSCSI driver

domain

Network

driver

domain


User VM User VM

NB gntdev NB

NF BF NF BF

qemu

xapi xenopsd

libxl

healthd

Domain

manager

vswitch

networkd

tapdisk

blktap3

storaged

syslogd vswitch

networkd

tapdisk

blktap3

storaged

tapdisk

blktap3

storaged

gntdev gntdev

FLASK policy

restricting access

D

o

m

0

.

.

.

dbus over v4v dbus over v4v

Xen

ARM Hypervisor

Fully functional for ARM v7 & v8

ARM v7: Versatile Express, Arndale & Samsung Chromebook

ARM v8: Fast Model

Xen 4.3 for ARM Servers

ARM SOC

Xen + ARM = a perfect Match

ARM Architecture Features for Virtualization

Hypervisor mode : EL2

Kernel mode : EL1

User mode : EL0

GIC

v2 GT

2 stage

MMU

I/O

Device Tree describes …

Hypercall Interface HVC

ARM SOC ARM Architecture Features for Virtualization

EL2

EL1

EL0

GIC

v2 GT

2 stage

MMU

I/O


HVC


Xen Hypervisor


EL2

EL1

EL0

GIC

v2 GT

2 stage

MMU

I/O


HVC


Xen Hypervisor

Any Xen Guest VM (including Dom0)

Kernel

User Space

HVC


EL2

EL1

EL0

GIC

v2 GT

2 stage

MMU

I/O


HVC


Xen Hypervisor

Dom0

only

Any Xen Guest VM (including Dom0)

Kernel

User Space

I/O

PV back

PV front I/O

HVC

One mode to rule them all

x86: PVHVM P P VS VH

x86: PVH P P P VH

ARM v7 & v8 P VH VH VH


Optimal performance

HVM mode/domain

PV mode/domain

Code Size of x86 and ARM Hypervisors

X86 Hypervisor 100K -120K LOC Any x86 CPU

ARM Hypervisor for mobile Devices

60K LOC ARM v5 – v7 (no virt extensions) (extra code for RT)

ARM Hypervisor for Servers

17K LOC ARM v7+ (virt extensions)

Mirage OS

Application stacks only running on Xen APIs

Works on any Xen based cloud or hosting service

Examples – ErlangOnXen.org : Erlang

– HalVM : Haskell

– Mirage OS : Ocaml

Benefits: – Small footprint

– Low startup latency

– Extremely fast migration of VMs

Library Operating Systems

Xen


Host HW

Guest VMn

Apps

HW Drivers

PV Back Ends Library OS embedded

in Language run-time

Dom0 Kernel

• Recently added to Xen Project incubator

• In beta stage : first release on its way

• Clean-slate protocols implementations, e.g. – TCP/IP, DNS, SSH, Openflow (switch/controller), HTTP, XMPP, ...

– New applications using next generation XAPI (disaggregated XAPI architecture)

Mirage OS

More info: http://www.slideshare.net/xen_com_mgr/ mirage-extreme-specialisation-of-virtual-appliances

What’s Next?

• Code Freeze now

• Xen ARM for Servers

• Extend scope of Xen Security Modules

• qxl Spice support for 3d acceleration

• Updated and improved libvirt drivers for Xen

• Lots of other stuff: – scalability, performance, better NUMA support, …

Coming in Xen 4.3 (Q2 2013)

More info: blog.xen.org/index.php/2013/02/11/xen-4-3-mid-release-roadmap-update

• Establish a shared test infrastructure – Most major contributors are duplicating effort

– Mirage OS provides interesting opportiunities

• Usability and better distro-integration – Example: Xen + XAPI in CentOS 6.4

• More focus on downstreams – Examples: OpenStack and Xen Orchestra

• Disaggregation in Xen toolstacks (e.g XAPI)

• Better Libvirt and virt-manager integration – Embed Xen more into the Linux eco-system and provide benefits for the

wider Linux community

What’s next (and already happening)

• Document Days

• Test Days

• Mailing Lists and IRC

• Find me and I can get you hooked up!

Getting Started with Xen Projects

Xen Hackathon, May 16-17, Dublin, Ireland @Google

Thank You!

Slides available under CC-BY-SA 3.0 From www.slideshare.net/xen_com_mgr

@lars_kurth FREENODE: lars_kurth

• News: blog.xenproject.org

• Web: xenproject.org – Help for IRC, Lists, …

– Stackoverflow like Q&A

• Wiki: wiki.xenproject.org

• Presentations: slideshare.net/xen_com_mgr

• Videos: vimeo.com/channels/xen

http://www.slideshare.net/xen_com_mgr