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Linuxcon EU : Virtualization in the Cloud featuring Xen and XCP
The document provides an extensive overview of the Xen hypervisor and its role in cloud virtualization, tracing its history from the late 1990s to contemporary advancements. It discusses various components and features of Xen, including Xen Cloud Platform (XCP), virtualization modes, security measures, and community contributions. Additionally, it highlights the architecture, functionalities, and advantages of using Xen in cloud environments, emphasizing its design for robustness, scalability, and security.
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Linuxcon EU : Virtualization in the Cloud featuring Xen and XCP
- 1. Virtualization in theCloud: Featuring Xen Lars Kurth Xen Community Manager lars.kurth@xen.org @lars_kurth FREENODE: lars_kurth @xen_com_mgr
- 2. A Brief Historyof Xen in the Cloud Late 90s XenoServer Project (Cambridge Univ.) Global Public Computing The XenoServer project is building public infrastructure for wide-area “This dissertation proposes a new distributed computing distributed computing. paradigm, termed global public computing, which allows any user to run any code anywhere. Such platforms price We envisage a world in which XenoServer computing resources, and ultimately charge users for execution platforms will be scattered across resources consumed.“ the globe and available for any member of the public to submit code for execution. Evangelos Kotsovinos, PhD dissertation, 2004
- 3. A Brief Historyof Xen in the Cloud Late 90s Oct ‘03 ‘06 ‘08 ‘09 ‘11 ‘12 XenoServer Project Amazon EC2 XCP 1.x (Cambridge Univ.) and Slicehost Cloud Mgmt launched Xen Presented Rackspace Linux 3.0 at SOSP Cloud XCP packages in Linux XCP Announced Xen for ARM based Servers PVH mode
- 4. The Xen Hypervisorwas designed for the Cloud straight from the outset!
- 5. Xen.org • Guardian ofXen Hypervisor and related OSS Projects • Xen Governance similar to Linux Kernel • Projects – Xen Hypervisor (led by 5 committers, 2 from Citrix) – Xen Cloud Platform aka XCP (led by Citrix) – Xen ARM : Xen for mobile devices (led by Samsung) – PVOPS : Xen components and support in Linux Kernel (led by Oracle) • 10+ vendors contributing more than 1% to the project (AWS, AMD, Citrix, GridCentric, Fujitsu, Huawei, iWeb, Intel, NSA, Oracle, Samsung, Suse, …)
- 6.
- 7. Hypervisor Architectures Type 1:Bare metal Hypervisor Type 2: OS ‘Hosted’ A pure Hypervisor that runs directly on the A Hypervisor that runs within a Host OS and hosts hardware and hosts Guest OS’s. Guest OS’s inside of it, using the host OS services to provide the virtual environment. VMn User-level VMM VMn VM1 User VM1 Apps VM0 Device Models VM0 Guest OS Guest OS and Apps and Apps Host OS Scheduler Hypervisor Ring-0 VM Monitor Device Drivers/Models Device Drivers “Kernel “ MMU Host HW Host HW I/O Memory CPUs I/O Memory CPUs Provides partition isolation + reliability, Low cost, no additional drivers higher security Ease of use & installation
- 8. Xen: Type 1with a Twist Control domain Thinner hypervisor (dom0) • Functionality moved to Dom0 Device Models VMn Using Linux PV OPS VM1 • Using Linux Device Drivers Drivers VM0 • PV, PV on HVM and PVH modes Guest OS • Sharing components with KVM Linux & BSD and Apps Hypervisor In other words Scheduler MMU XSM • Re-use of Dom0 kernel components I/O Memory CPUs Host HW • Ease of use & Installation • Isolation & Security 8
- 9. Xen and Linux •Xen Hypervisor is not in the Linux kernel • BUT: everything Xen and Xen Guests need to run is! • Xen packages are mostly in Linux distros – 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
- 10. Basic Xen Concepts Control Domain aka Dom0 Console • Dom0 kernel with drivers • Xen Management Toolstack VMn • Trusted Computing Base Control domain VM1 (dom0) Guest Domains One or more VM0 Toolstack driver, stub or • Your apps Dom0 Kernel service domains Guest OS and Apps • E.g. your cloud management stack Driver/Stub/Service Domain(s) Scheduler MMU XSM Hypervisor • A “driver, device model or control Host HW service in a box” I/O Memory CPUs • De-privileged and isolated • Lifetime: start, stop, kill 10
- 11. Xen Variants forServer & Cloud Xen Hypervisor XCP Toolstack / Console Default / XL (XM) Libvirt / VIRSH XAPI / XE Increased level of functionality and integration with other components Get Binaries from … Linux Distros Linux Distros Debian & Ubuntu ISO from Xen.org Products Oracle VM Huawei UVP Citrix XenServer Used by … Many Others More info: xen.org/community/presentations.html 11
- 12. Xen : Typesof Virtualization
- 13. PV Domains &Driver Domains Technology: Control domain Guest VMn Driver Domain (dom0) e.g. • Paravirtualization Apps • Disk Linux PV guests have limitations: • Network • limited set of virtual hardware PV Back Ends PV Front Ends PV Back End Advantages HW Drivers HW Driver • Fast • Works on any system Dom0 Kernel Guest OS Dom0 Kernel* (even without virt extensions) Xen Hypervisor Driver Domains • Security Host HW • Isolation I/O Memory CPUs • Reliability and Robustness *) Can be MiniOS 13
- 14. HVM & StubDomains Technology: Dom0 Guest VMn Stubdomn Guest VMn • Shows emulation using QEMU/Device Model (SW Virtualization) IO Emulation IO Emulation • In other situation HW can be used Device Model Device Model Disadvantages • Emulation slower than PV IO Event IO Event (mainly I/O devices) Dom0 Kernel VMEXIT Mini OS VMEXIT Advantages • No kernel support needed Xen Hypervisor Stub Domains Host HW • Security • Isolation • Reliability and Robustness 14
- 15. The Virtualization Spectrum VS Virtualized (SW) VH Virtualized (HW) P Paravirtualized Fully Virtualized (FV) VS VS VS VH FV with PV disk & network P VS VS VH HVM mode/domain PVHVM P P VS VH PVH x86 Xen 4.3 P P P VH PVH ARM v7+ Xen 4.3 P VH P VH PV mode/domain Fully Paravirtualized (PV) P P P P
- 16. The Virtualization Spectrum Optimal performance Scope for improvement Poor performance Fully Virtualized (FV) VS VS VS VH FV with PV disk & network P VS VS VH HVM mode/domain PVHVM P P VS VH PVH x86 Xen 4.3 P P P VH PVH ARM v7+ Xen 4.3 P VH P VH PV mode/domain Fully Paravirtualized (PV) P P P P
- 17. PVH Benefits • Solvesa number of historical problems with PV and HVM – AMD 64 bit and x86-64 architecture is not a good match for PV for Privileged Instructions and Page Tables – Will allow to simplify the Xen and PVOPS architecture in the longer term • Fastest of PV and HVM on all architectures – No need for emulation – Uses HW virtualization where it is fastest – Uses PV where PV is fastest – Should provide the best trade-offs for most work-loads More info: wiki.xen.org/wiki/Virtualization_Spectrum & More info: xen.org/xensummit/xs12na_talks/M9.html
- 18.
- 19. XCP – XenCloud Platform Complete stack for server virtualization • Extends Xen to cover multiple hosts • Adds further functionality and integrations for cloud, storage and networking to Xen HV • GPLv2 • XenServer is a commercial XCP distro Two Flavours • Appliance (ISO using CentOS Dom0) • Packages in Debian & Ubuntu (more distros to come)
- 20. Major XCP Features •VM lifecycle: live snapshots, checkpoint, migration • Resource pools: flexible storage and networking • Event tracking: progress, notification • Upgrade and patching capabilities • Real-time performance monitoring and alerting • Built-in support and templates for Windows and Linux guests • Open vSwitch support built-in (default) More info: wiki.xen.org/wiki/XCP_Release_Features
- 21. XCP 1.6 Beta •Internal Improvements: Xen 4.1.2, CentOS 5.7 with kernel 2.6.32.43, Open vSwitch 1.4.1 • New format Windows drivers: installable by Windows Update Service • Networking: Better VLAN scalability, LACP bonding, IPv6 • More guest OS templates: Ubuntu Precise 12.04, RHEL/CentOS, Oracle Enterprise Linux 6.1 & 6.2, Windows 8 • Storage XenMotion: – Migrate VMs between hosts or pools without shared storage – Move a VM’s disks between storage repositories while the VM is running More info: xen.org/download/xcp/releasenotes_1.6.0.html & More info: xen.org/download/xcp/index_1.6.0.html
- 22. XCP and CloudOrchestration Stacks
- 23. Challenges for FOSShypervisors
- 24. “Security and QoS/Reliabilityare amongst the top 3 blockers for cloud adoption” www.colt.net/cio-research
- 25. System characteristics cloudusers care about: “Robustness, Performance, Scalability & Security” Results XCP User Survey 2012 – 90% of users quoted these as most important attributes
- 26. Disaggregation • Split ControlDomain into Driver, Stub and Service Domains – See: ”Breaking up is hard to do” @ Xen Papers – See: “Domain 0 Disaggregation for XCP and XenServer” • Unique benefit of the Xen architecture – Robustness: ability to safely restart parts of the system (e.g. just 275ms outage from failed Ethernet driver) – Performance: lightweight, Xen scheduler – Scalability: more distributed system (less reliable on Dom0) – Security: Minimum privilege; Narrow interfaces; Restart domains • Used today by Qubes OS and Citrix XenClient XT • Prototypes for XCP and XenServer
- 27. User VM User VM NF BF NF BF NB gntdev NB gntdev gntdev Dom0 Network NFS/ Dom0 Qemu xapi Qemu Network NFS/ Local drivers iSCSI drivers iSCSI storage Domain manager drivers . drivers drivers qemu . qemu healthd storaged storaged storaged networkd . networkd xenopsd tapdisk . tapdisk tapdisk libxl vswitch blktap3 xapi vswitch blktap3 blktap3 syslogd eth eth Dom0 eth eth scsi Xen NIC CPU CPU NIC RAM RAM NIC NIC (or (or SR- (or SR- (or SR- RAID SR-IOV IOV VF) IOV VF) IOV VF) VF)
- 28. User VM User VM NF BF NF BF NB gntdev NB gntdev gntdev Dom0 Network NFS/ Qemu xapi Logging Qemu Network NFS/ Local driver iSCSI domain domain domain domain driver iSCSI storage Domain domain driver domain driver driver manager domain domain domain qemu qemu healthd storaged storaged storaged networkd networkd xenopsd tapdisk tapdisk tapdisk libxl vswitch blktap3 xapi syslogd vswitch blktap3 blktap3 dbus over v4v eth eth eth eth scsi Xen CPU CPU NIC NIC RAM RAM NIC NIC (or SR- (or SR- (or SR- (or SR- RAID IOV VF) IOV VF) IOV VF) IOV VF)
- 29. 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) – Developed, maintained and contributed to Xen by NSA – Generalized Security Framework for Xen – Compatible with SELinux (tools, architecture) – XSM object classes maps onto Xen features • XSM together with Disaggregation – Security sensitive Desktop use-cases developed for the NSA 29
- 30. User VM User VM NF BF NF BF NB gntdev NB gntdev gntdev Dom0 Network NFS/ Qemu xapi Logging Qemu Network NFS/ Local driver iSCSI domain domain domain domain driver iSCSI storage Domain domain driver domain driver driver manager domain domain domain qemu qemu healthd storaged storaged storaged networkd networkd xenopsd tapdisk tapdisk tapdisk libxl vswitch blktap3 xapi syslogd vswitch blktap3 blktap3 dbus over v4v eth eth eth eth scsi XSM policy restricting access Xen NIC CPU CPU NIC RAM RAM NIC NIC (or (or SR- (or SR- (or SR- RAID SR-IOV IOV VF) IOV VF) IOV VF) VF)
- 31. News from theXen Community
- 32. Cool new functionality& initiatives • New PVH virtualization mode (Oracle) – Patches being up-streamed to Xen and Linux (3.7 & 3.8) as we speak – Sweet spot for performance • Xen for ARM servers (using new PVH mode) – Cortex A15/ ARM v7: can start guests on Versatile Express; Samsung Chromebook next – ARM v8: porting work started on simulator and patches being up-streamed • New Xen ports – FreeBSD Xen port (SpectraLogic & HP) – Xen MIPS port (by BroadCom) • Language run-times running on bare-metal Xen – ErlangOnXen.org , Openmirage.org More info: wiki.xen.org/wiki/Xen_Roadmap/4.3 & wiki.xen.org/wiki/XCP_Roadmap
- 33.
- 34. • Designed forthe Cloud : many advantages for cloud use! – Resilience, Robustness & Scalability – Security: Small surface of attack, Isolation & Advanced Security Features • Widely used by Cloud Providers and Vendors • XCP – Ready for use with cloud orchestration stacks – Packages in Linux distros: flexibility and choice • Open Source with a large community and eco-system – Exciting new developments in the pipeline
- 35. • IRC: ##xen@ FREENODE • Mailing List: xen-users & xen-api (lists.xen.org) • Wiki: wiki.xen.org • Ecosystem pages: xen.org/community/ecosystem.html • Presentations & Videos: xen.org/community/presentations.html • Xen Day Barcelona @ LinuxCon, Nov 8th : xen.org/community/events/xendaybarcelona2012.html @lars_kurth Questions … @xen_com_mgr FREENODE: lars_kurth Slides available under CC-BY-SA 3.0 From www.slideshare.net/xen_com_mgr
Editor's Notes
- #3 Xen started out as a research project at Cambridge University, UK in the late 90’sAim: to define infrastructure for wide-area distributed computingVision: was pretty much cloud computing as we know it todayOut of the project came a dissertation by EvangelosKotsovinos which defines Global Public Computing in terms ofDistributed resourcesPublic compute infrastructureCharge users for resources consumedWhat we understand as Public Cloud Computing AWS style today
- #5 Hold this thought! We will come back to this later….!
- #6 Overall, we have around 40-45 vendors contributing to the project per year and
- #8 Type 1 hypervisor: example ESXSimple architecture; Hypervisor replaces the kernelNo need to provide rich “process” semantics, like “user”, filesystems, etc.Device drivers need to be rewritten for each hardware platformType 2 is hosted: example kvm- The hypervisor is just a driver that typically works with user-level monitor.HW access is intercepted by the ring 0- VM monitor passed to the User level Virtual Monitor, which passes requests to the kernelRe-use of device drivers is traded off against security and a large trusted computing base (green)
- #13 PVOPS is the Kernel Infrastructure to run a PV Hypervisor on top of Linux
- #15 Device Model emulated in QEMUModels for newer devices are much faster, but for now PV is even faster
- #18 APIC = Advanced Programmable Interrupt ControllerIDT = Interrupt Descriptor Table
- #21 VM lifecycle (start, stop, resume) ... automation is the key pointLive snapshots: Takes a snapshot of a live VM (e.g. for disaster recovery or migration)Resource pools (multiple physical machines): XS & XCP onlylive migration: VM is backed up while running, onto shared storage (e.g. NFS) in a pool and when completed restarted elsewhere in that pool. disaster recovery: you can find lots of information on how this works at http://support.citrix.com/servlet/KbServlet/download/17141-102-19301/XenServer_Pool_Replication_-_Disaster_Recovery.pdf (the key point is that I can back up the metadata for the entire VM)Flexible storage: XAPI does hide details for storage and networkingI.e. I apply generic commands (NFS, NETAPP, iSCSI ... once its created they all appear the same) from XAPI. I only need to know the storage type when I create storage and network objects (OOL)Upgrading a host to a later version of XCP (all my configs and VMs stay the same) …and patching (broken now - bug, can apply security patches to XCP/XS or Dom0 but not DomU)
- #22 * Host Architectural Improvements. XCP 1.5 now runs on the Xen 4.1 hypervisor, provides GPT (new partition table type) support and a smaller, more scalable Dom0. * GPU Pass-Through. Enables a physical GPU to be assigned to a VM providing high-end graphics. * Increased Performance and Scale. Supported limits have been increased to 1 TB memory for XCP hosts, and up to16 virtual processors and 128 GB virtual memory for VMs. Improved XCP Tools with smaller footprint. * Networking Improvements. Open vSwitch is now the default networking stack in XCP 1.5 and now provides formal support for Active-Backup NIC bonding. * Enhanced Guest OS Support. Support for Ubuntu 10.04 (32/64-bit).Updated support for Debian Squeeze 6.0 64-bit, Oracle Enterprise Linux6.0 (32/64-bit) and SLES 10 SP4 (32/64-bit). Experimental VM templates for CentOS 6.0 (32/64-bit), Ubuntu 10.10 (32/64-bit) and Solaris 10. * Virtual Appliance Support (vApp). Ability to create multi-VM and boot sequenced virtual appliances (vApps) that integrate with Integrated Site Recovery and High Availability. vApps can be easily imported and exported using the Open Virtualization Format (OVF) standard.
- #24 PVOPS is the Kernel Infrastructure to run a PV Hypervisor on top of Linux
- #25 Just one example of a survey, many morehttp://www.colt.net/cio-research/z2-cloud-2.htmlAccording to many surveys, security is actually the main reason which makes or breaks cloud adoptionBetter security means more adoptionConcerns about security means slowed adoption
- #26 Just one example of a survey, many morehttp://www.colt.net/cio-research/z2-cloud-2.htmlAccording to many surveys, security is actually the main reason which makes or breaks cloud adoptionBetter security means more adoptionConcerns about security means slowed adoption
- #30 Ask some questions
- #32 PVOPS is the Kernel Infrastructure to run a PV Hypervisor on top of Linux
- #35 Performance : similar to other hypervisorsMaturity: Tried & Tested, Most Problems that are Problems are well knownOpen source: Good body of Knowledge, Tools