File:  [NetBSD Developer Wiki] / wikisrc / ports / xen / howto.mdwn
Revision 1.29: download - view: text, annotated - select for diffs
Wed Dec 24 15:17:25 2014 UTC (4 years, 11 months ago) by gdt
Branches: MAIN
CVS tags: HEAD
Strengthen hint to use amd64 hardware.

Move 4.2-last-i386 bit, and add TODO to clarify.

Note that 3.1 supports non-PAE on i386.

Suggest netbsd-7 for those wanting to learn vs run production systems.

    1: Introduction
    2: ============
    3: 
    4: [![[Xen
    5: screenshot]](http://www.netbsd.org/gallery/in-Action/hubertf-xens.png)](../../gallery/in-Action/hubertf-xen.png)
    6: 
    7: Xen is a virtual machine monitor or hypervisor for x86 hardware
    8: (i686-class or higher), which supports running multiple guest
    9: operating systems on a single physical machine.  With Xen, one uses
   10: the Xen kernel to control the CPU, memory and console, a dom0
   11: operating system which mediates access to other hardware (e.g., disks,
   12: network, USB), and one or more domU operating systems which operate in
   13: an unprivileged virtualized environment.  IO requests from the domU
   14: systems are forwarded by the hypervisor (Xen) to the dom0 to be
   15: fulfilled.
   16: 
   17: Xen supports two styles of guests.  The original is Para-Virtualized
   18: (PV) which means that the guest OS does not attempt to access hardware
   19: directly, but instead makes hypercalls to the hypervisor.  This is
   20: analogous to a user-space program making system calls.  (The dom0
   21: operating system uses PV calls for some functions, such as updating
   22: memory mapping page tables, but has direct hardware access for disk
   23: and network.)   PV guests must be specifically coded for Xen.
   24: 
   25: The more recent style is HVM, which means that the guest does not have
   26: code for Xen and need not be aware that it is running under Xen.
   27: Attempts to access hardware registers are trapped and emulated.  This
   28: style is less efficient but can run unmodified guests.
   29: 
   30: Generally any amd64 machine will work with Xen and PV guests.  In
   31: theory i386 computers without amd64 support can be used for Xen <=
   32: 4.2, but we have no recent reports of this working (this is a hint).
   33: For HVM guests, the VT or VMX cpu feature (Intel) or SVM/HVM/VT
   34: (amd64) is needed; "cpuctl identify 0" will show this.  TODO: Clean up
   35: and check the above features.
   36: 
   37: At boot, the dom0 kernel is loaded as a module with Xen as the kernel.
   38: The dom0 can start one or more domUs.  (Booting is explained in detail
   39: in the dom0 section.)
   40: 
   41: NetBSD supports Xen in that it can serve as dom0, be used as a domU,
   42: and that Xen kernels and tools are available in pkgsrc.  This HOWTO
   43: attempts to address both the case of running a NetBSD dom0 on hardware
   44: and running domUs under it (NetBSD and other), and also running NetBSD
   45: as a domU in a VPS.
   46: 
   47: Some versions of Xen support "PCI passthrough", which means that
   48: specific PCI devices can be made available to a specific domU instead
   49: of the dom0.  This can be useful to let a domU run X11, or access some
   50: network interface or other peripheral.
   51: 
   52: Prerequisites
   53: -------------
   54: 
   55: Installing NetBSD/Xen is not extremely difficult, but it is more
   56: complex than a normal installation of NetBSD.
   57: In general, this HOWTO is occasionally overly restrictive about how
   58: things must be done, guiding the reader to stay on the established
   59: path when there are no known good reasons to stray.
   60: 
   61: This HOWTO presumes a basic familiarity with the Xen system
   62: architecture.  This HOWTO presumes familiarity with installing NetBSD
   63: on i386/amd64 hardware and installing software from pkgsrc.
   64: See also the [Xen website](http://www.xenproject.org/).
   65: 
   66: History
   67: -------
   68: 
   69: NetBSD used to support Xen2; this has been removed.
   70: 
   71: Before NetBSD's native bootloader could support Xen, the use of
   72: grub was recommended.  If necessary, see the
   73: [old grub information](/ports/xen/howto-grub/).
   74: 
   75: Versions of Xen and NetBSD
   76: ==========================
   77: 
   78: Most of the installation concepts and instructions are independent
   79: of Xen version and NetBSD version.  This section gives advice on
   80: which version to choose.  Versions not in pkgsrc and older unsupported
   81: versions of NetBSD are intentionally ignored.
   82: 
   83: Xen
   84: ---
   85: 
   86: In NetBSD, xen is provided in pkgsrc, via matching pairs of packages
   87: xenkernel and xentools.  We will refer only to the kernel versions,
   88: but note that both packages must be installed together and must have
   89: matching versions.
   90: 
   91: xenkernel3 and xenkernel33 provide Xen 3.1 and 3.3.  These no longer
   92: receive security patches and should not be used.  Xen 3.1 supports PCI
   93: passthrough.  Xen 3.1 supports non-PAE on i386.
   94: 
   95: xenkernel41 provides Xen 4.1.  This is no longer maintained by Xen,
   96: but as of 2014-12 receives backported security patches.  It is a
   97: reasonable although trailing-edge choice.
   98: 
   99: xenkernel42 provides Xen 4.2.  This is maintained by Xen, but old as
  100: of 2014-12.
  101: 
  102: Ideally newer versions of Xen will be added to pkgsrc.
  103: 
  104: Note that NetBSD support is called XEN3.  It works with 3.1 through
  105: 4.2 because the hypercall interface has been stable.
  106: 
  107: Xen command program
  108: -------------------
  109: 
  110: Early Xen used a program called "xm" to manipulate the system from the
  111: dom0.  Starting in 4.1, a replacement program with similar behavior
  112: called "xl" is provided.  In 4.2 and later, "xl" is preferred.  4.4 is
  113: the last version that has "xm".
  114: 
  115: NetBSD
  116: ------
  117: 
  118: The netbsd-5, netbsd-6, netbsd-7, and -current branches are all
  119: reasonable choices, with more or less the same considerations for
  120: non-Xen use.  Therefore, netbsd-6 is recommended as the stable version
  121: of the most recent release for production use.  For those wanting to
  122: learn Xen or without production stability concerns, netbsd-7 is likely
  123: most appropriate.
  124: 
  125: As of NetBSD 6, a NetBSD domU will support multiple vcpus.  There is
  126: no SMP support for NetBSD as dom0.  (The dom0 itself doesn't really
  127: need SMP; the lack of support is really a problem when using a dom0 as
  128: a normal computer.)
  129: 
  130: Architecture
  131: ------------
  132: 
  133: Xen itself can run on i386 or amd64 machines.  (Practically, almost
  134: any computer where one would want to run Xen supports amd64.)  If
  135: using an i386 NetBSD kernel for the dom0, PAE is required (PAE
  136: versions are built by default).  While i386 dom0 works fine, amd64 is
  137: recommended as more normal.
  138: 
  139: Xen 4.2 is the last version to support i386 as a host.  TODO: Clarify
  140: if this is about the CPU having to be amd64, or about the dom0 kernel
  141: having to be amd64.
  142: 
  143: One can then run i386 domUs and amd64 domUs, in any combination.  If
  144: running an i386 NetBSD kernel as a domU, the PAE version is required.
  145: (Note that emacs (at least) fails if run on i386 with PAE when built
  146: without, and vice versa, presumably due to bugs in the undump code.)
  147: 
  148: Recommendation
  149: --------------
  150: 
  151: Therefore, this HOWTO recommends running xenkernel42 (and xentools42),
  152: xl, the NetBSD 6 stable branch, and to use amd64 as the dom0.  Either
  153: the i386 or amd64 of NetBSD may be used as domUs.
  154: 
  155: NetBSD as a dom0
  156: ================
  157: 
  158: NetBSD can be used as a dom0 and works very well.  The following
  159: sections address installation, updating NetBSD, and updating Xen.
  160: Note that it doesn't make sense to talk about installing a dom0 OS
  161: without also installing Xen itself.  We first address installing
  162: NetBSD, which is not yet a dom0, and then adding Xen, pivoting the
  163: NetBSD install to a dom0 install by just changing the kernel and boot
  164: configuration.
  165: 
  166: Styles of dom0 operation
  167: ------------------------
  168: 
  169: There are two basic ways to use Xen.  The traditional method is for
  170: the dom0 to do absolutely nothing other than providing support to some
  171: number of domUs.  Such a system was probably installed for the sole
  172: purpose of hosting domUs, and sits in a server room on a UPS.
  173: 
  174: The other way is to put Xen under a normal-usage computer, so that the
  175: dom0 is what the computer would have been without Xen, perhaps a
  176: desktop or laptop.  Then, one can run domUs at will.  Purists will
  177: deride this as less secure than the previous approach, and for a
  178: computer whose purpose is to run domUs, they are right.  But Xen and a
  179: dom0 (without domUs) is not meaingfully less secure than the same
  180: things running without Xen.  One can boot Xen or boot regular NetBSD
  181: alternately with little problems, simply refraining from starting the
  182: Xen daemons when not running Xen.
  183: 
  184: Note that NetBSD as dom0 does not support multiple CPUs.  This will
  185: limit the performance of the Xen/dom0 workstation approach.
  186: 
  187: Installation of NetBSD
  188: ----------------------
  189: 
  190: First,
  191: [install NetBSD/amd64](/guide/inst/)
  192: just as you would if you were not using Xen.
  193: However, the partitioning approach is very important.
  194: 
  195: If you want to use RAIDframe for the dom0, there are no special issues
  196: for Xen.  Typically one provides RAID storage for the dom0, and the
  197: domU systems are unaware of RAID.  The 2nd-stage loader bootxx_* skips
  198: over a RAID1 header to find /boot from a filesystem within a RAID
  199: partition; this is no different when booting Xen.
  200: 
  201: There are 4 styles of providing backing storage for the virtual disks
  202: used by domUs: raw partitions, LVM, file-backed vnd(4), and SAN,
  203: 
  204: With raw partitions, one has a disklabel (or gpt) partition sized for
  205: each virtual disk to be used by the domU.  (If you are able to predict
  206: how domU usage will evolve, please add an explanation to the HOWTO.
  207: Seriously, needs tend to change over time.)
  208: 
  209: One can use [lvm(8)](/guide/lvm/) to create logical devices to use
  210: for domU disks.  This is almost as efficient as raw disk partitions
  211: and more flexible.  Hence raw disk partitions should typically not
  212: be used.
  213: 
  214: One can use files in the dom0 filesystem, typically created by dd'ing
  215: /dev/zero to create a specific size.  This is somewhat less efficient,
  216: but very convenient, as one can cp the files for backup, or move them
  217: between dom0 hosts.
  218: 
  219: Finally, in theory one can place the files backing the domU disks in a
  220: SAN.  (This is an invitation for someone who has done this to add a
  221: HOWTO page.)
  222: 
  223: Installation of Xen
  224: -------------------
  225: 
  226: In the dom0, install sysutils/xenkernel42 and sysutils/xentools42 from
  227: pkgsrc (or another matching pair).
  228: See [the pkgsrc
  229: documentation](http://www.NetBSD.org/docs/pkgsrc/) for help with pkgsrc.
  230: 
  231: For Xen 3.1, support for HVM guests is in sysutils/xentool3-hvm.  More
  232: recent versions have HVM support integrated in the main xentools
  233: package.  It is entirely reasonable to run only PV guests.
  234: 
  235: Next you need to install the selected Xen kernel itself, which is
  236: installed by pkgsrc as "/usr/pkg/xen*-kernel/xen.gz".  Copy it to /.
  237: For debugging, one may copy xen-debug.gz; this is conceptually similar
  238: to DIAGNOSTIC and DEBUG in NetBSD.  xen-debug.gz is basically only
  239: useful with a serial console.  Then, place a NetBSD XEN3_DOM0 kernel
  240: in /, copied from releasedir/amd64/binary/kernel/netbsd-XEN3_DOM0.gz
  241: of a NetBSD build.  Both xen and NetBSD may be left compressed.  (If
  242: using i386, use releasedir/i386/binary/kernel/netbsd-XEN3PAE_DOM0.gz.)
  243: 
  244: In a dom0 kernel, kernfs is mandatory for xend to comunicate with the
  245: kernel, so ensure that /kern is in fstab.
  246: 
  247: Because you already installed NetBSD, you have a working boot setup
  248: with an MBR bootblock, either bootxx_ffsv1 or bootxx_ffsv2 at the
  249: beginning of your root filesystem, /boot present, and likely
  250: /boot.cfg.  (If not, fix before continuing!)
  251: 
  252: See boot.cfg(5) for an example.  The basic line is
  253: 
  254: "menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=256M"
  255: 
  256: which specifies that the dom0 should have 256M, leaving the rest to be
  257: allocated for domUs.
  258: 
  259: As with non-Xen systems, you should have a line to boot /netbsd (a
  260: kernel that works without Xen) and fallback versions of the non-Xen
  261: kernel, Xen, and the dom0 kernel.
  262: 
  263: The [HowTo on Installing into
  264: RAID-1](http://mail-index.NetBSD.org/port-xen/2006/03/01/0010.html)
  265: explains how to set up booting a dom0 with Xen using grub with
  266: NetBSD's RAIDframe.  (This is obsolete with the use of NetBSD's native
  267: boot.)
  268: 
  269: Configuring Xen
  270: ---------------
  271: 
  272: Now, you have a system that will boot Xen and the dom0 kernel, and
  273: just run the dom0 kernel.  There will be no domUs, and none can be
  274: started because you still have to configure the dom0 tools.
  275: 
  276: For 3.3 (and probably 3.1), add to rc.conf (but note that you should
  277: have installed 4.2):
  278:   xend=YES
  279:   xenbackendd=YES
  280: 
  281: For 4.1 and 4.2, add to rc.conf:
  282:   xend=YES
  283:   xencommons=YES
  284: 
  285: Note that xend is for supporting "xm", and should only be used if
  286: you plan on using "xm".  Do NOT enable xend if you plan on using
  287: "xl" as it will cause problems.
  288: 
  289: Updating NetBSD in a dom0
  290: -------------------------
  291: 
  292: This is just like updating NetBSD on bare hardware, assuming the new
  293: version supports the version of Xen you are running.  Generally, one
  294: replaces the kernel and reboots, and then overlays userland binaries
  295: and adjusts /etc.
  296: 
  297: Note that one must update both the non-Xen kernel typically used for
  298: rescue purposes and the DOM0 kernel used with Xen.
  299: 
  300: To convert from grub to /boot, install an mbr bootblock with fdisk,
  301: bootxx_ with installboot, /boot and /boot.cfg.  This really should be
  302: no different than completely reinstalling boot blocks on a non-Xen
  303: system.
  304: 
  305: Updating Xen versions
  306: ---------------------
  307: 
  308: Updating Xen is conceptually not difficult, but can run into all the
  309: issues found when installing Xen.  Assuming migration from 4.1 to 4.2,
  310: remove the xenkernel41 and xentools41 packages and install the
  311: xenkernel42 and xentools42 packages.  Copy the 4.2 xen.gz to /.
  312: 
  313: Ensure that the contents of /etc/rc.d/xen* are correct.  Enable the
  314: correct set of daemons.  Ensure that the domU config files are valid
  315: for the new version.
  316: 
  317: 
  318: Unprivileged domains (domU)
  319: ===========================
  320: 
  321: This section describes general concepts about domUs.  It does not
  322: address specific domU operating systems or how to install them.
  323: 
  324: Provided Resources for PV domains
  325: ---------------------------------
  326: 
  327: TODO: Explain that domUs get cpu, memory, disk and network.
  328: Explain that randomness can be an issue.
  329: 
  330: Virtual disks
  331: -------------
  332: 
  333: TODO: Explain how to set up files for vnd and that one should write all zeros to preallocate.
  334: TODO: Explain in what NetBSD versions sparse vnd files do and don't work.
  335: 
  336: Virtual Networking
  337: ------------------
  338: 
  339: TODO: explain xvif concept, and that it's general.
  340: 
  341: There are two normal styles: bridging and NAT.
  342: 
  343: With bridging, the domU perceives itself to be on the same network as
  344: the dom0.  For server virtualization, this is usually best.
  345: 
  346: With NAT, the domU perceives itself to be behind a NAT running on the
  347: dom0.  This is often appropriate when running Xen on a workstation.
  348: 
  349: One can construct arbitrary other configurations, but there is no
  350: script support.
  351: 
  352: Config files
  353: ------------
  354: 
  355: TODO: give example config files.   Use both lvm and vnd.
  356: 
  357: TODO: explain the mess with 3 arguments for disks and how to cope (0x1).
  358: 
  359: Starting domains
  360: ----------------
  361: 
  362: TODO: Explain "xm start" and "xl start".  Explain rc.d/xendomains.
  363: 
  364: TODO: Explain why 4.1 rc.d/xendomains has xl, when one should use xm
  365: on 4.1.
  366: 
  367: Creating specific unprivileged domains (domU)
  368: =============================================
  369: 
  370: Creating domUs is almost entirely independent of operating system.  We
  371: first explain NetBSD, and then differences for Linux and Solaris.
  372: 
  373: Creating an unprivileged NetBSD domain (domU)
  374: ---------------------------------------------
  375: 
  376: Once you have *domain0* running, you need to start the xen tool daemon
  377: (`/usr/pkg/share/examples/rc.d/xend start`) and the xen backend daemon
  378: (`/usr/pkg/share/examples/rc.d/xenbackendd start` for Xen3\*,
  379: `/usr/pkg/share/examples/rc.d/xencommons start` for Xen4.\*). Make sure
  380: that `/dev/xencons` and `/dev/xenevt` exist before starting `xend`. You
  381: can create them with this command:
  382: 
  383:     # cd /dev && sh MAKEDEV xen
  384: 
  385: xend will write logs to `/var/log/xend.log` and
  386: `/var/log/xend-debug.log`. You can then control xen with the xm tool.
  387: 'xm list' will show something like:
  388: 
  389:     # xm list
  390:     Name              Id  Mem(MB)  CPU  State  Time(s)  Console
  391:     Domain-0           0       64    0  r----     58.1
  392: 
  393: 'xm create' allows you to create a new domain. It uses a config file in
  394: PKG\_SYSCONFDIR for its parameters. By default, this file will be in
  395: `/usr/pkg/etc/xen/`. On creation, a kernel has to be specified, which
  396: will be executed in the new domain (this kernel is in the *domain0* file
  397: system, not on the new domain virtual disk; but please note, you should
  398: install the same kernel into *domainU* as `/netbsd` in order to make
  399: your system tools, like savecore(8), work). A suitable kernel is
  400: provided as part of the i386 and amd64 binary sets: XEN3\_DOMU.
  401: 
  402: Here is an /usr/pkg/etc/xen/nbsd example config file:
  403: 
  404:     #  -*- mode: python; -*-
  405:     #============================================================================
  406:     # Python defaults setup for 'xm create'.
  407:     # Edit this file to reflect the configuration of your system.
  408:     #============================================================================
  409: 
  410:     #----------------------------------------------------------------------------
  411:     # Kernel image file. This kernel will be loaded in the new domain.
  412:     kernel = "/home/bouyer/netbsd-XEN3_DOMU"
  413:     #kernel = "/home/bouyer/netbsd-INSTALL_XEN3_DOMU"
  414: 
  415:     # Memory allocation (in megabytes) for the new domain.
  416:     memory = 128
  417: 
  418:     # A handy name for your new domain. This will appear in 'xm list',
  419:     # and you can use this as parameters for xm in place of the domain
  420:     # number. All domains must have different names.
  421:     #
  422:     name = "nbsd"
  423: 
  424:     # The number of virtual CPUs this domain has.
  425:     #
  426:     vcpus = 1
  427: 
  428:     #----------------------------------------------------------------------------
  429:     # Define network interfaces for the new domain.
  430: 
  431:     # Number of network interfaces (must be at least 1). Default is 1.
  432:     nics = 1
  433: 
  434:     # Define MAC and/or bridge for the network interfaces.
  435:     #
  436:     # The MAC address specified in ``mac'' is the one used for the interface
  437:     # in the new domain. The interface in domain0 will use this address XOR'd
  438:     # with 00:00:00:01:00:00 (i.e. aa:00:00:51:02:f0 in our example). Random
  439:     # MACs are assigned if not given.
  440:     #
  441:     # ``bridge'' is a required parameter, which will be passed to the
  442:     # vif-script called by xend(8) when a new domain is created to configure
  443:     # the new xvif interface in domain0.
  444:     #
  445:     # In this example, the xvif is added to bridge0, which should have been
  446:     # set up prior to the new domain being created -- either in the
  447:     # ``network'' script or using a /etc/ifconfig.bridge0 file.
  448:     #
  449:     vif = [ 'mac=aa:00:00:50:02:f0, bridge=bridge0' ]
  450: 
  451:     #----------------------------------------------------------------------------
  452:     # Define the disk devices you want the domain to have access to, and
  453:     # what you want them accessible as.
  454:     #
  455:     # Each disk entry is of the form:
  456:     #
  457:     #   phy:DEV,VDEV,MODE
  458:     #
  459:     # where DEV is the device, VDEV is the device name the domain will see,
  460:     # and MODE is r for read-only, w for read-write.  You can also create
  461:     # file-backed domains using disk entries of the form:
  462:     #
  463:     #   file:PATH,VDEV,MODE
  464:     #
  465:     # where PATH is the path to the file used as the virtual disk, and VDEV
  466:     # and MODE have the same meaning as for ``phy'' devices.
  467:     #
  468:     # VDEV doesn't really matter for a NetBSD guest OS (it's just used as an index),
  469:     # but it does for Linux.
  470:     # Worse, the device has to exist in /dev/ of domain0, because xm will
  471:     # try to stat() it. This means that in order to load a Linux guest OS
  472:     # from a NetBSD domain0, you'll have to create /dev/hda1, /dev/hda2, ...
  473:     # on domain0, with the major/minor from Linux :(
  474:     # Alternatively it's possible to specify the device number in hex,
  475:     # e.g. 0x301 for /dev/hda1, 0x302 for /dev/hda2, etc ...
  476: 
  477:     disk = [ 'phy:/dev/wd0e,0x1,w' ]
  478:     #disk = [ 'file:/var/xen/nbsd-disk,0x01,w' ]
  479:     #disk = [ 'file:/var/xen/nbsd-disk,0x301,w' ]
  480: 
  481:     #----------------------------------------------------------------------------
  482:     # Set the kernel command line for the new domain.
  483: 
  484:     # Set root device. This one does matter for NetBSD
  485:     root = "xbd0"
  486:     # extra parameters passed to the kernel
  487:     # this is where you can set boot flags like -s, -a, etc ...
  488:     #extra = ""
  489: 
  490:     #----------------------------------------------------------------------------
  491:     # Set according to whether you want the domain restarted when it exits.
  492:     # The default is False.
  493:     #autorestart = True
  494: 
  495:     # end of nbsd config file ====================================================
  496: 
  497: When a new domain is created, xen calls the
  498: `/usr/pkg/etc/xen/vif-bridge` script for each virtual network interface
  499: created in *domain0*. This can be used to automatically configure the
  500: xvif?.? interfaces in *domain0*. In our example, these will be bridged
  501: with the bridge0 device in *domain0*, but the bridge has to exist first.
  502: To do this, create the file `/etc/ifconfig.bridge0` and make it look
  503: like this:
  504: 
  505:     create
  506:     !brconfig $int add ex0 up
  507: 
  508: (replace `ex0` with the name of your physical interface). Then bridge0
  509: will be created on boot. See the bridge(4) man page for details.
  510: 
  511: So, here is a suitable `/usr/pkg/etc/xen/vif-bridge` for xvif?.? (a
  512: working vif-bridge is also provided with xentools20) configuring:
  513: 
  514:     #!/bin/sh
  515:     #============================================================================
  516:     # $NetBSD: howto.mdwn,v 1.29 2014/12/24 15:17:25 gdt Exp $
  517:     #
  518:     # /usr/pkg/etc/xen/vif-bridge
  519:     #
  520:     # Script for configuring a vif in bridged mode with a dom0 interface.
  521:     # The xend(8) daemon calls a vif script when bringing a vif up or down.
  522:     # The script name to use is defined in /usr/pkg/etc/xen/xend-config.sxp
  523:     # in the ``vif-script'' field.
  524:     #
  525:     # Usage: vif-bridge up|down [var=value ...]
  526:     #
  527:     # Actions:
  528:     #    up     Adds the vif interface to the bridge.
  529:     #    down   Removes the vif interface from the bridge.
  530:     #
  531:     # Variables:
  532:     #    domain name of the domain the interface is on (required).
  533:     #    vifq   vif interface name (required).
  534:     #    mac    vif MAC address (required).
  535:     #    bridge bridge to add the vif to (required).
  536:     #
  537:     # Example invocation:
  538:     #
  539:     # vif-bridge up domain=VM1 vif=xvif1.0 mac="ee:14:01:d0:ec:af" bridge=bridge0
  540:     #
  541:     #============================================================================
  542: 
  543:     # Exit if anything goes wrong
  544:     set -e
  545: 
  546:     echo "vif-bridge $*"
  547: 
  548:     # Operation name.
  549:     OP=$1; shift
  550: 
  551:     # Pull variables in args into environment
  552:     for arg ; do export "${arg}" ; done
  553: 
  554:     # Required parameters. Fail if not set.
  555:     domain=${domain:?}
  556:     vif=${vif:?}
  557:     mac=${mac:?}
  558:     bridge=${bridge:?}
  559: 
  560:     # Optional parameters. Set defaults.
  561:     ip=${ip:-''}   # default to null (do nothing)
  562: 
  563:     # Are we going up or down?
  564:     case $OP in
  565:     up) brcmd='add' ;;
  566:     down)   brcmd='delete' ;;
  567:     *)
  568:         echo 'Invalid command: ' $OP
  569:         echo 'Valid commands are: up, down'
  570:         exit 1
  571:         ;;
  572:     esac
  573: 
  574:     # Don't do anything if the bridge is "null".
  575:     if [ "${bridge}" = "null" ] ; then
  576:         exit
  577:     fi
  578: 
  579:     # Don't do anything if the bridge doesn't exist.
  580:     if ! ifconfig -l | grep "${bridge}" >/dev/null; then
  581:         exit
  582:     fi
  583: 
  584:     # Add/remove vif to/from bridge.
  585:     ifconfig x${vif} $OP
  586:     brconfig ${bridge} ${brcmd} x${vif}
  587: 
  588: Now, running
  589: 
  590:     xm create -c /usr/pkg/etc/xen/nbsd
  591: 
  592: should create a domain and load a NetBSD kernel in it. (Note: `-c`
  593: causes xm to connect to the domain's console once created.) The kernel
  594: will try to find its root file system on xbd0 (i.e., wd0e) which hasn't
  595: been created yet. wd0e will be seen as a disk device in the new domain,
  596: so it will be 'sub-partitioned'. We could attach a ccd to wd0e in
  597: *domain0* and partition it, newfs and extract the NetBSD/i386 or amd64
  598: tarballs there, but there's an easier way: load the
  599: `netbsd-INSTALL_XEN3_DOMU` kernel provided in the NetBSD binary sets.
  600: Like other install kernels, it contains a ramdisk with sysinst, so you
  601: can install NetBSD using sysinst on your new domain.
  602: 
  603: If you want to install NetBSD/Xen with a CDROM image, the following line
  604: should be used in the `/usr/pkg/etc/xen/nbsd` file:
  605: 
  606:     disk = [ 'phy:/dev/wd0e,0x1,w', 'phy:/dev/cd0a,0x2,r' ]
  607: 
  608: After booting the domain, the option to install via CDROM may be
  609: selected. The CDROM device should be changed to `xbd1d`.
  610: 
  611: Once done installing, `halt -p` the new domain (don't reboot or halt, it
  612: would reload the INSTALL\_XEN3\_DOMU kernel even if you changed the
  613: config file), switch the config file back to the XEN3\_DOMU kernel, and
  614: start the new domain again. Now it should be able to use `root on xbd0a`
  615: and you should have a second, functional NetBSD system on your xen
  616: installation.
  617: 
  618: When the new domain is booting you'll see some warnings about *wscons*
  619: and the pseudo-terminals. These can be fixed by editing the files
  620: `/etc/ttys` and `/etc/wscons.conf`. You must disable all terminals in
  621: `/etc/ttys`, except *console*, like this:
  622: 
  623:     console "/usr/libexec/getty Pc"         vt100   on secure
  624:     ttyE0   "/usr/libexec/getty Pc"         vt220   off secure
  625:     ttyE1   "/usr/libexec/getty Pc"         vt220   off secure
  626:     ttyE2   "/usr/libexec/getty Pc"         vt220   off secure
  627:     ttyE3   "/usr/libexec/getty Pc"         vt220   off secure
  628: 
  629: Finally, all screens must be commented out from `/etc/wscons.conf`.
  630: 
  631: It is also desirable to add
  632: 
  633:     powerd=YES
  634: 
  635: in rc.conf. This way, the domain will be properly shut down if
  636: `xm shutdown -R` or `xm shutdown -H` is used on the domain0.
  637: 
  638: Your domain should be now ready to work, enjoy.
  639: 
  640: Creating an unprivileged Linux domain (domU)
  641: --------------------------------------------
  642: 
  643: Creating unprivileged Linux domains isn't much different from
  644: unprivileged NetBSD domains, but there are some details to know.
  645: 
  646: First, the second parameter passed to the disk declaration (the '0x1' in
  647: the example below)
  648: 
  649:     disk = [ 'phy:/dev/wd0e,0x1,w' ]
  650: 
  651: does matter to Linux. It wants a Linux device number here (e.g. 0x300
  652: for hda). Linux builds device numbers as: (major \<\< 8 + minor). So,
  653: hda1 which has major 3 and minor 1 on a Linux system will have device
  654: number 0x301. Alternatively, devices names can be used (hda, hdb, ...)
  655: as xentools has a table to map these names to devices numbers. To export
  656: a partition to a Linux guest we can use:
  657: 
  658:     disk = [ 'phy:/dev/wd0e,0x300,w' ]
  659:     root = "/dev/hda1 ro"
  660: 
  661: and it will appear as /dev/hda on the Linux system, and be used as root
  662: partition.
  663: 
  664: To install the Linux system on the partition to be exported to the guest
  665: domain, the following method can be used: install sysutils/e2fsprogs
  666: from pkgsrc. Use mke2fs to format the partition that will be the root
  667: partition of your Linux domain, and mount it. Then copy the files from a
  668: working Linux system, make adjustments in `/etc` (fstab, network
  669: config). It should also be possible to extract binary packages such as
  670: .rpm or .deb directly to the mounted partition using the appropriate
  671: tool, possibly running under NetBSD's Linux emulation. Once the
  672: filesystem has been populated, umount it. If desirable, the filesystem
  673: can be converted to ext3 using tune2fs -j. It should now be possible to
  674: boot the Linux guest domain, using one of the vmlinuz-\*-xenU kernels
  675: available in the Xen binary distribution.
  676: 
  677: To get the linux console right, you need to add:
  678: 
  679:     extra = "xencons=tty1"
  680: 
  681: to your configuration since not all linux distributions auto-attach a
  682: tty to the xen console.
  683: 
  684: Creating an unprivileged Solaris domain (domU)
  685: ----------------------------------------------
  686: 
  687: Download an Opensolaris [release](http://opensolaris.org/os/downloads/)
  688: or [development snapshot](http://genunix.org/) DVD image. Attach the DVD
  689: image to a MAN.VND.4 device. Copy the kernel and ramdisk filesystem
  690: image to your dom0 filesystem.
  691: 
  692:     dom0# mkdir /root/solaris
  693:     dom0# vnconfig vnd0 osol-1002-124-x86.iso
  694:     dom0# mount /dev/vnd0a /mnt
  695: 
  696:     ## for a 64-bit guest
  697:     dom0# cp /mnt/boot/amd64/x86.microroot /root/solaris
  698:     dom0# cp /mnt/platform/i86xpv/kernel/amd64/unix /root/solaris
  699: 
  700:     ## for a 32-bit guest
  701:     dom0# cp /mnt/boot/x86.microroot /root/solaris
  702:     dom0# cp /mnt/platform/i86xpv/kernel/unix /root/solaris
  703: 
  704:     dom0# umount /mnt
  705:           
  706: 
  707: Keep the MAN.VND.4 configured. For some reason the boot process stalls
  708: unless the DVD image is attached to the guest as a "phy" device. Create
  709: an initial configuration file with the following contents. Substitute
  710: */dev/wd0k* with an empty partition at least 8 GB large.
  711: 
  712:     memory = 640
  713:     name = 'solaris'
  714:     disk = [ 'phy:/dev/wd0k,0,w' ]
  715:     disk += [ 'phy:/dev/vnd0d,6:cdrom,r' ]
  716:     vif = [ 'bridge=bridge0' ]
  717:     kernel = '/root/solaris/unix'
  718:     ramdisk = '/root/solaris/x86.microroot'
  719:     # for a 64-bit guest
  720:     extra = '/platform/i86xpv/kernel/amd64/unix - nowin -B install_media=cdrom'
  721:     # for a 32-bit guest
  722:     #extra = '/platform/i86xpv/kernel/unix - nowin -B install_media=cdrom'
  723:           
  724: 
  725: Start the guest.
  726: 
  727:     dom0# xm create -c solaris.cfg
  728:     Started domain solaris
  729:                           v3.3.2 chgset 'unavailable'
  730:     SunOS Release 5.11 Version snv_124 64-bit
  731:     Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.
  732:     Use is subject to license terms.
  733:     Hostname: opensolaris
  734:     Remounting root read/write
  735:     Probing for device nodes ...
  736:     WARNING: emlxs: ddi_modopen drv/fct failed: err 2
  737:     Preparing live image for use
  738:     Done mounting Live image
  739:           
  740: 
  741: Make sure the network is configured. Note that it can take a minute for
  742: the xnf0 interface to appear.
  743: 
  744:     opensolaris console login: jack
  745:     Password: jack
  746:     Sun Microsystems Inc.   SunOS 5.11      snv_124 November 2008
  747:     jack@opensolaris:~$ pfexec sh
  748:     sh-3.2# ifconfig -a
  749:     sh-3.2# exit
  750:           
  751: 
  752: Set a password for VNC and start the VNC server which provides the X11
  753: display where the installation program runs.
  754: 
  755:     jack@opensolaris:~$ vncpasswd
  756:     Password: solaris
  757:     Verify: solaris
  758:     jack@opensolaris:~$ cp .Xclients .vnc/xstartup
  759:     jack@opensolaris:~$ vncserver :1
  760:           
  761: 
  762: From a remote machine connect to the VNC server. Use `ifconfig xnf0` on
  763: the guest to find the correct IP address to use.
  764: 
  765:     remote$ vncviewer 172.18.2.99:1
  766:           
  767: 
  768: It is also possible to launch the installation on a remote X11 display.
  769: 
  770:     jack@opensolaris:~$ export DISPLAY=172.18.1.1:0
  771:     jack@opensolaris:~$ pfexec gui-install
  772:            
  773: 
  774: After the GUI installation is complete you will be asked to reboot.
  775: Before that you need to determine the ZFS ID for the new boot filesystem
  776: and update the configuration file accordingly. Return to the guest
  777: console.
  778: 
  779:     jack@opensolaris:~$ pfexec zdb -vvv rpool | grep bootfs
  780:                     bootfs = 43
  781:     ^C
  782:     jack@opensolaris:~$
  783:            
  784: 
  785: The final configuration file should look like this. Note in particular
  786: the last line.
  787: 
  788:     memory = 640
  789:     name = 'solaris'
  790:     disk = [ 'phy:/dev/wd0k,0,w' ]
  791:     vif = [ 'bridge=bridge0' ]
  792:     kernel = '/root/solaris/unix'
  793:     ramdisk = '/root/solaris/x86.microroot'
  794:     extra = '/platform/i86xpv/kernel/amd64/unix -B zfs-bootfs=rpool/43,bootpath="/xpvd/xdf@0:a"'
  795:            
  796: 
  797: Restart the guest to verify it works correctly.
  798: 
  799:     dom0# xm destroy solaris
  800:     dom0# xm create -c solaris.cfg
  801:     Using config file "./solaris.cfg".
  802:     v3.3.2 chgset 'unavailable'
  803:     Started domain solaris
  804:     SunOS Release 5.11 Version snv_124 64-bit
  805:     Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.
  806:     Use is subject to license terms.
  807:     WARNING: emlxs: ddi_modopen drv/fct failed: err 2
  808:     Hostname: osol
  809:     Configuring devices.
  810:     Loading smf(5) service descriptions: 160/160
  811:     svccfg import warnings. See /var/svc/log/system-manifest-import:default.log .
  812:     Reading ZFS config: done.
  813:     Mounting ZFS filesystems: (6/6)
  814:     Creating new rsa public/private host key pair
  815:     Creating new dsa public/private host key pair
  816: 
  817:     osol console login:
  818:            
  819: 
  820: Using PCI devices in guest domains
  821: ----------------------------------
  822: 
  823: The domain0 can give other domains access to selected PCI devices. This
  824: can allow, for example, a non-privileged domain to have access to a
  825: physical network interface or disk controller. However, keep in mind
  826: that giving a domain access to a PCI device most likely will give the
  827: domain read/write access to the whole physical memory, as PCs don't have
  828: an IOMMU to restrict memory access to DMA-capable device. Also, it's not
  829: possible to export ISA devices to non-domain0 domains (which means that
  830: the primary VGA adapter can't be exported. A guest domain trying to
  831: access the VGA registers will panic).
  832: 
  833: This functionality is only available in NetBSD-5.1 (and later) domain0
  834: and domU. If the domain0 is NetBSD, it has to be running Xen 3.1, as
  835: support has not been ported to later versions at this time.
  836: 
  837: For a PCI device to be exported to a domU, is has to be attached to the
  838: `pciback` driver in domain0. Devices passed to the domain0 via the
  839: pciback.hide boot parameter will attach to `pciback` instead of the
  840: usual driver. The list of devices is specified as `(bus:dev.func)`,
  841: where bus and dev are 2-digit hexadecimal numbers, and func a
  842: single-digit number:
  843: 
  844:     pciback.hide=(00:0a.0)(00:06.0)
  845: 
  846: pciback devices should show up in the domain0's boot messages, and the
  847: devices should be listed in the `/kern/xen/pci` directory.
  848: 
  849: PCI devices to be exported to a domU are listed in the `pci` array of
  850: the domU's config file, with the format `'0000:bus:dev.func'`
  851: 
  852:     pci = [ '0000:00:06.0', '0000:00:0a.0' ]
  853: 
  854: In the domU an `xpci` device will show up, to which one or more pci
  855: busses will attach. Then the PCI drivers will attach to PCI busses as
  856: usual. Note that the default NetBSD DOMU kernels do not have `xpci` or
  857: any PCI drivers built in by default; you have to build your own kernel
  858: to use PCI devices in a domU. Here's a kernel config example:
  859: 
  860:     include         "arch/i386/conf/XEN3_DOMU"
  861:     #include         "arch/i386/conf/XENU"           # in NetBSD 3.0
  862: 
  863:     # Add support for PCI busses to the XEN3_DOMU kernel
  864:     xpci* at xenbus ?
  865:     pci* at xpci ?
  866: 
  867:     # Now add PCI and related devices to be used by this domain
  868:     # USB Controller and Devices
  869: 
  870:     # PCI USB controllers
  871:     uhci*   at pci? dev ? function ?        # Universal Host Controller (Intel)
  872: 
  873:     # USB bus support
  874:     usb*    at uhci?
  875: 
  876:     # USB Hubs
  877:     uhub*   at usb?
  878:     uhub*   at uhub? port ? configuration ? interface ?
  879: 
  880:     # USB Mass Storage
  881:     umass*  at uhub? port ? configuration ? interface ?
  882:     wd*     at umass?
  883:     # SCSI controllers
  884:     ahc*    at pci? dev ? function ?        # Adaptec [23]94x, aic78x0 SCSI
  885: 
  886:     # SCSI bus support (for both ahc and umass)
  887:     scsibus* at scsi?
  888: 
  889:     # SCSI devices
  890:     sd*     at scsibus? target ? lun ?      # SCSI disk drives
  891:     cd*     at scsibus? target ? lun ?      # SCSI CD-ROM drives
  892: 
  893: 
  894: NetBSD as a domU in a VPS
  895: =========================
  896: 
  897: The bulk of the HOWTO is about using NetBSD as a dom0 on your own
  898: hardware.  This section explains how to deal with Xen in a domU as a
  899: virtual private server where you do not control or have access to the
  900: dom0.
  901: 
  902: TODO: Perhaps reference panix, prmgr, amazon as interesting examples.
  903: 
  904: TODO: Somewhere, discuss pvgrub and py-grub to load the domU kernel
  905: from the domU filesystem.

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