File:  [NetBSD Developer Wiki] / wikisrc / ports / xen / howto.mdwn
Revision 1.24: download - view: text, annotated - select for diffs
Wed Dec 24 01:35:40 2014 UTC (4 years, 11 months ago) by gdt
Branches: MAIN
CVS tags: HEAD
clarify dom0/domU scope vs VPS

    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.  For HVM
   31: guests, the VT or VMX cpu feature (Intel) or SVM/HVM/VT (amd64) is
   32: needed; "cpuctl identify 0" will show this.  TODO: Clean up and check
   33: the above features.  TODO: Explain if i386 (non-amd64) machines can
   34: still be used --- I think that the requirement to use PAE kernels is
   35: about the hypervisor being amd64 only.
   36: 
   37: At boot, the dom0 kernel is loaded as 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.xen.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](/xen/howto-grub/).
   74: 
   75: Versions of Xen and NetBSD
   76: ==========================
   77: 
   78: Most of the installation concepts and instructions are independent of
   79: Xen version.  This section gives advice on which version to choose.
   80: Versions not in pkgsrc and older unsupported versions of NetBSD are
   81: inentionally 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.
   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, "xm" is no longer available.
  113: 
  114: NetBSD
  115: ------
  116: 
  117: The netbsd-5, netbsd-6, netbsd-7, and -current branches are all
  118: reasonable choices, with more or less the same considerations for
  119: non-Xen use.  Therefore, netbsd-6 is recommended as the stable version
  120: of the most recent release.
  121: 
  122: As of NetBSD 6, a NetBSD domU will support multiple vcpus.  There is
  123: no SMP support for NetBSD as dom0.  (The dom0 itself doesn't really
  124: need SMP; the lack of support is really a problem when using a dom0 as
  125: a normal computer.)
  126: 
  127: Architecture
  128: ------------
  129: 
  130: Xen is basically amd64 only at this point.  One can either run i386
  131: domains or amd64 domains.  If running i386, PAE versions are required,
  132: for both dom0 and domU.  These versions are built by default in NetBSD
  133: releases.  While i386 dom0 works fine, amd64 is recommended as more
  134: normal.  (Note that emacs (at least) fails if run on i386 with PAE when
  135: built without, and vice versa, presumably due to bugs in the undump
  136: code.)
  137: 
  138: Recommendation
  139: --------------
  140: 
  141: Therefore, this HOWTO recommends running xenkernel42 (and xentools42),
  142: xl, the NetBSD 6 stable branch, and to use amd64 as the dom0.  Either
  143: the i386 or amd64 of NetBSD may be used as domUs.
  144: 
  145: NetBSD as a dom0
  146: ================
  147: 
  148: NetBSD can be used as a dom0 and works very well.  The following
  149: sections address installation, updating NetBSD, and updating Xen.
  150: Note that it doesn't make sense to talk about installing a dom0 OS
  151: without also installing Xen itself.  We first address installing
  152: NetBSD, which is not yet a dom0, and then adding Xen, pivoting the
  153: NetBSD install to a dom0 install by just changing the kernel and boot
  154: configuration.
  155: 
  156: Styles of dom0 operation
  157: ------------------------
  158: 
  159: There are two basic ways to use Xen.  The traditional method is for
  160: the dom0 to do absolutely nothing other than providing support to some
  161: number of domUs.  Such a system was probably installed for the sole
  162: purpose of hosting domUs, and sits in a server room on a UPS.
  163: 
  164: The other way is to put Xen under a normal-usage computer, so that the
  165: dom0 is what the computer would have been without Xen, perhaps a
  166: desktop or laptop.  Then, one can run domUs at will.  Purists will
  167: deride this as less secure than the previous approach, and for a
  168: computer whose purpose is to run domUs, they are right.  But Xen and a
  169: dom0 (without domUs) is not meaingfully less secure than the same
  170: things running without Xen.  One can boot Xen or boot regular NetBSD
  171: alternately with little problems, simply refraining from starting the
  172: Xen daemons when not running Xen.
  173: 
  174: Note that NetBSD as dom0 does not support multiple CPUs.  This will
  175: limit the performance of the Xen/dom0 workstation approach.
  176: 
  177: Installation of NetBSD
  178: ----------------------
  179: 
  180: First,
  181: [install NetBSD/amd64](../../docs/guide/en/chap-inst.html)
  182: just as you would if you were not using Xen.
  183: However, the partitioning approach is very important.
  184: 
  185: If you want to use RAIDframe for the dom0, there are no special issues
  186: for Xen.  Typically one provides RAID storage for the dom0, and the
  187: domU systems are unaware of RAID.  The 2nd-stage loader bootxx_* skips
  188: over a RAID1 header to find /boot from a filesystem within a RAID
  189: partition; this is no different when booting Xen.
  190: 
  191: There are 4 styles of providing backing storage for the virtual disks
  192: used by domUs: raw partitions, LVM, file-backed vnd(4), and SAN,
  193: 
  194: With raw partitions, one has a disklabel (or gpt) partition sized for
  195: each virtual disk to be used by the domU.  (If you are able to predict
  196: how domU usage will evolve, please add an explanation to the HOWTO.
  197: Seriously, needs tend to change over time.)
  198: 
  199: One can use lvm(8) to create logical devices to use for domU disks.
  200: This is almost as efficient sa raw disk partitions and more flexible.
  201: Hence raw disk partitions should typically not be used.
  202: 
  203: One can use files in the dom0 filesystem, typically created by dd'ing
  204: /dev/zero to create a specific size.  This is somewhat less efficient,
  205: but very convenient, as one can cp the files for backup, or move them
  206: between dom0 hosts.
  207: 
  208: Finally, in theory one can place the files backing the domU disks in a
  209: SAN.  (This is an invitation for someone who has done this to add a
  210: HOWTO page.)
  211: 
  212: Installation of Xen
  213: -------------------
  214: 
  215: In the dom0, install sysutils/xenkernel42 and sysutils/xentools42 from
  216: pkgsrc (or another matching pair).
  217: See [the pkgsrc
  218: documentation](http://www.NetBSD.org/docs/pkgsrc/) for help with pkgsrc.
  219: 
  220: For Xen 3.1, support for HVM guests is in sysutils/xentool3-hvm.  More
  221: recent versions have HVM support integrated in the main xentools
  222: package.  It is entirely reasonable to run only PV guests.
  223: 
  224: Next you need to install the selected Xen kernel itself, which is
  225: installed by pkgsrc as "/usr/pkg/xen*-kernel/xen.gz".  Copy it to /.
  226: For debugging, one may copy xen-debug.gz; this is conceptually similar
  227: to DIAGNOSTIC and DEBUG in NetBSD.  xen-debug.gz is basically only
  228: useful with a serial console.  Then, place a NetBSD XEN3_DOM0 kernel
  229: in /, copied from releasedir/amd64/binary/kernel/netbsd-XEN3_DOM0.gz
  230: of a NetBSD build.  Both xen and NetBSD may be left compressed.  (If
  231: using i386, use releasedir/i386/binary/kernel/netbsd-XEN3PAE_DOM0.gz.)
  232: 
  233: In a dom0 kernel, kernfs is mandatory for xend to comunicate with the
  234: kernel, so ensure that /kern is in fstab.
  235: 
  236: Because you already installed NetBSD, you have a working boot setup
  237: with an MBR bootblock, either bootxx_ffsv1 or bootxx_ffsv2 at the
  238: beginning of your root filesystem, /boot present, and likely
  239: /boot.cfg.  (If not, fix before continuing!)
  240: 
  241: See boot.cfg(5) for an example.  The basic line is
  242: 
  243: "menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=256M"
  244: 
  245: which specifies that the dom0 should have 256M, leaving the rest to be
  246: allocated for domUs.
  247: 
  248: As with non-Xen systems, you should have a line to boot /netbsd (a
  249: kernel that works without Xen) and fallback versions of the non-Xen
  250: kernel, Xen, and the dom0 kernel.
  251: 
  252: Configuring Xen
  253: ---------------
  254: 
  255: Now, you have a system that will boot Xen and the dom0 kernel, and
  256: just run the dom0 kernel.  There will be no domUs, and none can be
  257: started because you still have to configure the dom0 tools.
  258: 
  259: For 3.3 (and probably 3.1), add to rc.conf (but note that you should
  260: have installed 4.2):
  261:   xend=YES
  262:   xenbackendd=YES
  263: 
  264: For 4.1 and 4.2, add to rc.conf:
  265:   xend=YES
  266:   xencommons=YES
  267: 
  268: Updating NetBSD in a dom0
  269: -------------------------
  270: 
  271: This is just like updating NetBSD on bare hardware, assuming the new
  272: version supports the version of Xen you are running.  Generally, one
  273: replaces the kernel and reboots, and then overlays userland binaries
  274: and adjusts /etc.
  275: 
  276: Note that one must update both the non-Xen kernel typically used for
  277: rescue purposes and the DOM0 kernel used with Xen.
  278: 
  279: To convert from grub to /boot, install an mbr bootblock with fdisk,
  280: bootxx_ with installboot, /boot and /boot.cfg.  This really should be
  281: no different than completely reinstalling boot blocks on a non-Xen
  282: system.
  283: 
  284: Updating Xen versions
  285: ---------------------
  286: 
  287: Updating Xen is conceptually not difficult, but can run into all the
  288: issues found when installing Xen.  Assuming migration from 4.1 to 4.2,
  289: remove the xenkernel41 and xentools41 packages and install the
  290: xenkernel42 and xentools42 packages.  Copy the 4.2 xen.gz to /.
  291: 
  292: Ensure that the contents of /etc/rc.d/xen* are correct.  Enable the
  293: correct set of daemons.  Ensure that the domU config files are valid
  294: for the new version.
  295: 
  296: Creating unprivileged domains (domU)
  297: ====================================
  298: 
  299: Creating domUs is almost entirely independent of operating system.  We
  300: first explain NetBSD, and then differences for Linux and Solaris.
  301: 
  302: Creating an unprivileged NetBSD domain (domU)
  303: ---------------------------------------------
  304: 
  305: Once you have *domain0* running, you need to start the xen tool daemon
  306: (`/usr/pkg/share/examples/rc.d/xend start`) and the xen backend daemon
  307: (`/usr/pkg/share/examples/rc.d/xenbackendd start` for Xen3\*,
  308: `/usr/pkg/share/examples/rc.d/xencommons start` for Xen4.\*). Make sure
  309: that `/dev/xencons` and `/dev/xenevt` exist before starting `xend`. You
  310: can create them with this command:
  311: 
  312:     # cd /dev && sh MAKEDEV xen
  313: 
  314: xend will write logs to `/var/log/xend.log` and
  315: `/var/log/xend-debug.log`. You can then control xen with the xm tool.
  316: 'xm list' will show something like:
  317: 
  318:     # xm list
  319:     Name              Id  Mem(MB)  CPU  State  Time(s)  Console
  320:     Domain-0           0       64    0  r----     58.1
  321: 
  322: 'xm create' allows you to create a new domain. It uses a config file in
  323: PKG\_SYSCONFDIR for its parameters. By default, this file will be in
  324: `/usr/pkg/etc/xen/`. On creation, a kernel has to be specified, which
  325: will be executed in the new domain (this kernel is in the *domain0* file
  326: system, not on the new domain virtual disk; but please note, you should
  327: install the same kernel into *domainU* as `/netbsd` in order to make
  328: your system tools, like MAN.SAVECORE.8, work). A suitable kernel is
  329: provided as part of the i386 and amd64 binary sets: XEN3\_DOMU.
  330: 
  331: Here is an /usr/pkg/etc/xen/nbsd example config file:
  332: 
  333:     #  -*- mode: python; -*-
  334:     #============================================================================
  335:     # Python defaults setup for 'xm create'.
  336:     # Edit this file to reflect the configuration of your system.
  337:     #============================================================================
  338: 
  339:     #----------------------------------------------------------------------------
  340:     # Kernel image file. This kernel will be loaded in the new domain.
  341:     kernel = "/home/bouyer/netbsd-XEN3_DOMU"
  342:     #kernel = "/home/bouyer/netbsd-INSTALL_XEN3_DOMU"
  343: 
  344:     # Memory allocation (in megabytes) for the new domain.
  345:     memory = 128
  346: 
  347:     # A handy name for your new domain. This will appear in 'xm list',
  348:     # and you can use this as parameters for xm in place of the domain
  349:     # number. All domains must have different names.
  350:     #
  351:     name = "nbsd"
  352: 
  353:     # The number of virtual CPUs this domain has.
  354:     #
  355:     vcpus = 1
  356: 
  357:     #----------------------------------------------------------------------------
  358:     # Define network interfaces for the new domain.
  359: 
  360:     # Number of network interfaces (must be at least 1). Default is 1.
  361:     nics = 1
  362: 
  363:     # Define MAC and/or bridge for the network interfaces.
  364:     #
  365:     # The MAC address specified in ``mac'' is the one used for the interface
  366:     # in the new domain. The interface in domain0 will use this address XOR'd
  367:     # with 00:00:00:01:00:00 (i.e. aa:00:00:51:02:f0 in our example). Random
  368:     # MACs are assigned if not given.
  369:     #
  370:     # ``bridge'' is a required parameter, which will be passed to the
  371:     # vif-script called by xend(8) when a new domain is created to configure
  372:     # the new xvif interface in domain0.
  373:     #
  374:     # In this example, the xvif is added to bridge0, which should have been
  375:     # set up prior to the new domain being created -- either in the
  376:     # ``network'' script or using a /etc/ifconfig.bridge0 file.
  377:     #
  378:     vif = [ 'mac=aa:00:00:50:02:f0, bridge=bridge0' ]
  379: 
  380:     #----------------------------------------------------------------------------
  381:     # Define the disk devices you want the domain to have access to, and
  382:     # what you want them accessible as.
  383:     #
  384:     # Each disk entry is of the form:
  385:     #
  386:     #   phy:DEV,VDEV,MODE
  387:     #
  388:     # where DEV is the device, VDEV is the device name the domain will see,
  389:     # and MODE is r for read-only, w for read-write.  You can also create
  390:     # file-backed domains using disk entries of the form:
  391:     #
  392:     #   file:PATH,VDEV,MODE
  393:     #
  394:     # where PATH is the path to the file used as the virtual disk, and VDEV
  395:     # and MODE have the same meaning as for ``phy'' devices.
  396:     #
  397:     # VDEV doesn't really matter for a NetBSD guest OS (it's just used as an index),
  398:     # but it does for Linux.
  399:     # Worse, the device has to exist in /dev/ of domain0, because xm will
  400:     # try to stat() it. This means that in order to load a Linux guest OS
  401:     # from a NetBSD domain0, you'll have to create /dev/hda1, /dev/hda2, ...
  402:     # on domain0, with the major/minor from Linux :(
  403:     # Alternatively it's possible to specify the device number in hex,
  404:     # e.g. 0x301 for /dev/hda1, 0x302 for /dev/hda2, etc ...
  405: 
  406:     disk = [ 'phy:/dev/wd0e,0x1,w' ]
  407:     #disk = [ 'file:/var/xen/nbsd-disk,0x01,w' ]
  408:     #disk = [ 'file:/var/xen/nbsd-disk,0x301,w' ]
  409: 
  410:     #----------------------------------------------------------------------------
  411:     # Set the kernel command line for the new domain.
  412: 
  413:     # Set root device. This one does matter for NetBSD
  414:     root = "xbd0"
  415:     # extra parameters passed to the kernel
  416:     # this is where you can set boot flags like -s, -a, etc ...
  417:     #extra = ""
  418: 
  419:     #----------------------------------------------------------------------------
  420:     # Set according to whether you want the domain restarted when it exits.
  421:     # The default is False.
  422:     #autorestart = True
  423: 
  424:     # end of nbsd config file ====================================================
  425: 
  426: When a new domain is created, xen calls the
  427: `/usr/pkg/etc/xen/vif-bridge` script for each virtual network interface
  428: created in *domain0*. This can be used to automatically configure the
  429: xvif?.? interfaces in *domain0*. In our example, these will be bridged
  430: with the bridge0 device in *domain0*, but the bridge has to exist first.
  431: To do this, create the file `/etc/ifconfig.bridge0` and make it look
  432: like this:
  433: 
  434:     create
  435:     !brconfig $int add ex0 up
  436: 
  437: (replace `ex0` with the name of your physical interface). Then bridge0
  438: will be created on boot. See the MAN.BRIDGE.4 man page for details.
  439: 
  440: So, here is a suitable `/usr/pkg/etc/xen/vif-bridge` for xvif?.? (a
  441: working vif-bridge is also provided with xentools20) configuring:
  442: 
  443:     #!/bin/sh
  444:     #============================================================================
  445:     # $NetBSD: howto.mdwn,v 1.24 2014/12/24 01:35:40 gdt Exp $
  446:     #
  447:     # /usr/pkg/etc/xen/vif-bridge
  448:     #
  449:     # Script for configuring a vif in bridged mode with a dom0 interface.
  450:     # The xend(8) daemon calls a vif script when bringing a vif up or down.
  451:     # The script name to use is defined in /usr/pkg/etc/xen/xend-config.sxp
  452:     # in the ``vif-script'' field.
  453:     #
  454:     # Usage: vif-bridge up|down [var=value ...]
  455:     #
  456:     # Actions:
  457:     #    up     Adds the vif interface to the bridge.
  458:     #    down   Removes the vif interface from the bridge.
  459:     #
  460:     # Variables:
  461:     #    domain name of the domain the interface is on (required).
  462:     #    vifq   vif interface name (required).
  463:     #    mac    vif MAC address (required).
  464:     #    bridge bridge to add the vif to (required).
  465:     #
  466:     # Example invocation:
  467:     #
  468:     # vif-bridge up domain=VM1 vif=xvif1.0 mac="ee:14:01:d0:ec:af" bridge=bridge0
  469:     #
  470:     #============================================================================
  471: 
  472:     # Exit if anything goes wrong
  473:     set -e
  474: 
  475:     echo "vif-bridge $*"
  476: 
  477:     # Operation name.
  478:     OP=$1; shift
  479: 
  480:     # Pull variables in args into environment
  481:     for arg ; do export "${arg}" ; done
  482: 
  483:     # Required parameters. Fail if not set.
  484:     domain=${domain:?}
  485:     vif=${vif:?}
  486:     mac=${mac:?}
  487:     bridge=${bridge:?}
  488: 
  489:     # Optional parameters. Set defaults.
  490:     ip=${ip:-''}   # default to null (do nothing)
  491: 
  492:     # Are we going up or down?
  493:     case $OP in
  494:     up) brcmd='add' ;;
  495:     down)   brcmd='delete' ;;
  496:     *)
  497:         echo 'Invalid command: ' $OP
  498:         echo 'Valid commands are: up, down'
  499:         exit 1
  500:         ;;
  501:     esac
  502: 
  503:     # Don't do anything if the bridge is "null".
  504:     if [ "${bridge}" = "null" ] ; then
  505:         exit
  506:     fi
  507: 
  508:     # Don't do anything if the bridge doesn't exist.
  509:     if ! ifconfig -l | grep "${bridge}" >/dev/null; then
  510:         exit
  511:     fi
  512: 
  513:     # Add/remove vif to/from bridge.
  514:     ifconfig x${vif} $OP
  515:     brconfig ${bridge} ${brcmd} x${vif}
  516: 
  517: Now, running
  518: 
  519:     xm create -c /usr/pkg/etc/xen/nbsd
  520: 
  521: should create a domain and load a NetBSD kernel in it. (Note: `-c`
  522: causes xm to connect to the domain's console once created.) The kernel
  523: will try to find its root file system on xbd0 (i.e., wd0e) which hasn't
  524: been created yet. wd0e will be seen as a disk device in the new domain,
  525: so it will be 'sub-partitioned'. We could attach a ccd to wd0e in
  526: *domain0* and partition it, newfs and extract the NetBSD/i386 or amd64
  527: tarballs there, but there's an easier way: load the
  528: `netbsd-INSTALL_XEN3_DOMU` kernel provided in the NetBSD binary sets.
  529: Like other install kernels, it contains a ramdisk with sysinst, so you
  530: can install NetBSD using sysinst on your new domain.
  531: 
  532: If you want to install NetBSD/Xen with a CDROM image, the following line
  533: should be used in the `/usr/pkg/etc/xen/nbsd` file:
  534: 
  535:     disk = [ 'phy:/dev/wd0e,0x1,w', 'phy:/dev/cd0a,0x2,r' ]
  536: 
  537: After booting the domain, the option to install via CDROM may be
  538: selected. The CDROM device should be changed to `xbd1d`.
  539: 
  540: Once done installing, `halt -p` the new domain (don't reboot or halt, it
  541: would reload the INSTALL\_XEN3\_DOMU kernel even if you changed the
  542: config file), switch the config file back to the XEN3\_DOMU kernel, and
  543: start the new domain again. Now it should be able to use `root on xbd0a`
  544: and you should have a second, functional NetBSD system on your xen
  545: installation.
  546: 
  547: When the new domain is booting you'll see some warnings about *wscons*
  548: and the pseudo-terminals. These can be fixed by editing the files
  549: `/etc/ttys` and `/etc/wscons.conf`. You must disable all terminals in
  550: `/etc/ttys`, except *console*, like this:
  551: 
  552:     console "/usr/libexec/getty Pc"         vt100   on secure
  553:     ttyE0   "/usr/libexec/getty Pc"         vt220   off secure
  554:     ttyE1   "/usr/libexec/getty Pc"         vt220   off secure
  555:     ttyE2   "/usr/libexec/getty Pc"         vt220   off secure
  556:     ttyE3   "/usr/libexec/getty Pc"         vt220   off secure
  557: 
  558: Finally, all screens must be commented out from `/etc/wscons.conf`.
  559: 
  560: It is also desirable to add
  561: 
  562:     powerd=YES
  563: 
  564: in rc.conf. This way, the domain will be properly shut down if
  565: `xm shutdown -R` or `xm shutdown -H` is used on the domain0.
  566: 
  567: Your domain should be now ready to work, enjoy.
  568: 
  569: Creating an unprivileged Linux domain (domU)
  570: --------------------------------------------
  571: 
  572: Creating unprivileged Linux domains isn't much different from
  573: unprivileged NetBSD domains, but there are some details to know.
  574: 
  575: First, the second parameter passed to the disk declaration (the '0x1' in
  576: the example below)
  577: 
  578:     disk = [ 'phy:/dev/wd0e,0x1,w' ]
  579: 
  580: does matter to Linux. It wants a Linux device number here (e.g. 0x300
  581: for hda). Linux builds device numbers as: (major \<\< 8 + minor). So,
  582: hda1 which has major 3 and minor 1 on a Linux system will have device
  583: number 0x301. Alternatively, devices names can be used (hda, hdb, ...)
  584: as xentools has a table to map these names to devices numbers. To export
  585: a partition to a Linux guest we can use:
  586: 
  587:     disk = [ 'phy:/dev/wd0e,0x300,w' ]
  588:     root = "/dev/hda1 ro"
  589: 
  590: and it will appear as /dev/hda on the Linux system, and be used as root
  591: partition.
  592: 
  593: To install the Linux system on the partition to be exported to the guest
  594: domain, the following method can be used: install sysutils/e2fsprogs
  595: from pkgsrc. Use mke2fs to format the partition that will be the root
  596: partition of your Linux domain, and mount it. Then copy the files from a
  597: working Linux system, make adjustments in `/etc` (fstab, network
  598: config). It should also be possible to extract binary packages such as
  599: .rpm or .deb directly to the mounted partition using the appropriate
  600: tool, possibly running under NetBSD's Linux emulation. Once the
  601: filesystem has been populated, umount it. If desirable, the filesystem
  602: can be converted to ext3 using tune2fs -j. It should now be possible to
  603: boot the Linux guest domain, using one of the vmlinuz-\*-xenU kernels
  604: available in the Xen binary distribution.
  605: 
  606: To get the linux console right, you need to add:
  607: 
  608:     extra = "xencons=tty1"
  609: 
  610: to your configuration since not all linux distributions auto-attach a
  611: tty to the xen console.
  612: 
  613: Creating an unprivileged Solaris domain (domU)
  614: ----------------------------------------------
  615: 
  616: Download an Opensolaris [release](http://opensolaris.org/os/downloads/)
  617: or [development snapshot](http://genunix.org/) DVD image. Attach the DVD
  618: image to a MAN.VND.4 device. Copy the kernel and ramdisk filesystem
  619: image to your dom0 filesystem.
  620: 
  621:     dom0# mkdir /root/solaris
  622:     dom0# vnconfig vnd0 osol-1002-124-x86.iso
  623:     dom0# mount /dev/vnd0a /mnt
  624: 
  625:     ## for a 64-bit guest
  626:     dom0# cp /mnt/boot/amd64/x86.microroot /root/solaris
  627:     dom0# cp /mnt/platform/i86xpv/kernel/amd64/unix /root/solaris
  628: 
  629:     ## for a 32-bit guest
  630:     dom0# cp /mnt/boot/x86.microroot /root/solaris
  631:     dom0# cp /mnt/platform/i86xpv/kernel/unix /root/solaris
  632: 
  633:     dom0# umount /mnt
  634:           
  635: 
  636: Keep the MAN.VND.4 configured. For some reason the boot process stalls
  637: unless the DVD image is attached to the guest as a "phy" device. Create
  638: an initial configuration file with the following contents. Substitute
  639: */dev/wd0k* with an empty partition at least 8 GB large.
  640: 
  641:     memory = 640
  642:     name = 'solaris'
  643:     disk = [ 'phy:/dev/wd0k,0,w' ]
  644:     disk += [ 'phy:/dev/vnd0d,6:cdrom,r' ]
  645:     vif = [ 'bridge=bridge0' ]
  646:     kernel = '/root/solaris/unix'
  647:     ramdisk = '/root/solaris/x86.microroot'
  648:     # for a 64-bit guest
  649:     extra = '/platform/i86xpv/kernel/amd64/unix - nowin -B install_media=cdrom'
  650:     # for a 32-bit guest
  651:     #extra = '/platform/i86xpv/kernel/unix - nowin -B install_media=cdrom'
  652:           
  653: 
  654: Start the guest.
  655: 
  656:     dom0# xm create -c solaris.cfg
  657:     Started domain solaris
  658:                           v3.3.2 chgset 'unavailable'
  659:     SunOS Release 5.11 Version snv_124 64-bit
  660:     Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.
  661:     Use is subject to license terms.
  662:     Hostname: opensolaris
  663:     Remounting root read/write
  664:     Probing for device nodes ...
  665:     WARNING: emlxs: ddi_modopen drv/fct failed: err 2
  666:     Preparing live image for use
  667:     Done mounting Live image
  668:           
  669: 
  670: Make sure the network is configured. Note that it can take a minute for
  671: the xnf0 interface to appear.
  672: 
  673:     opensolaris console login: jack
  674:     Password: jack
  675:     Sun Microsystems Inc.   SunOS 5.11      snv_124 November 2008
  676:     jack@opensolaris:~$ pfexec sh
  677:     sh-3.2# ifconfig -a
  678:     sh-3.2# exit
  679:           
  680: 
  681: Set a password for VNC and start the VNC server which provides the X11
  682: display where the installation program runs.
  683: 
  684:     jack@opensolaris:~$ vncpasswd
  685:     Password: solaris
  686:     Verify: solaris
  687:     jack@opensolaris:~$ cp .Xclients .vnc/xstartup
  688:     jack@opensolaris:~$ vncserver :1
  689:           
  690: 
  691: From a remote machine connect to the VNC server. Use `ifconfig xnf0` on
  692: the guest to find the correct IP address to use.
  693: 
  694:     remote$ vncviewer 172.18.2.99:1
  695:           
  696: 
  697: It is also possible to launch the installation on a remote X11 display.
  698: 
  699:     jack@opensolaris:~$ export DISPLAY=172.18.1.1:0
  700:     jack@opensolaris:~$ pfexec gui-install
  701:            
  702: 
  703: After the GUI installation is complete you will be asked to reboot.
  704: Before that you need to determine the ZFS ID for the new boot filesystem
  705: and update the configuration file accordingly. Return to the guest
  706: console.
  707: 
  708:     jack@opensolaris:~$ pfexec zdb -vvv rpool | grep bootfs
  709:                     bootfs = 43
  710:     ^C
  711:     jack@opensolaris:~$
  712:            
  713: 
  714: The final configuration file should look like this. Note in particular
  715: the last line.
  716: 
  717:     memory = 640
  718:     name = 'solaris'
  719:     disk = [ 'phy:/dev/wd0k,0,w' ]
  720:     vif = [ 'bridge=bridge0' ]
  721:     kernel = '/root/solaris/unix'
  722:     ramdisk = '/root/solaris/x86.microroot'
  723:     extra = '/platform/i86xpv/kernel/amd64/unix -B zfs-bootfs=rpool/43,bootpath="/xpvd/xdf@0:a"'
  724:            
  725: 
  726: Restart the guest to verify it works correctly.
  727: 
  728:     dom0# xm destroy solaris
  729:     dom0# xm create -c solaris.cfg
  730:     Using config file "./solaris.cfg".
  731:     v3.3.2 chgset 'unavailable'
  732:     Started domain solaris
  733:     SunOS Release 5.11 Version snv_124 64-bit
  734:     Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.
  735:     Use is subject to license terms.
  736:     WARNING: emlxs: ddi_modopen drv/fct failed: err 2
  737:     Hostname: osol
  738:     Configuring devices.
  739:     Loading smf(5) service descriptions: 160/160
  740:     svccfg import warnings. See /var/svc/log/system-manifest-import:default.log .
  741:     Reading ZFS config: done.
  742:     Mounting ZFS filesystems: (6/6)
  743:     Creating new rsa public/private host key pair
  744:     Creating new dsa public/private host key pair
  745: 
  746:     osol console login:
  747:            
  748: 
  749: Using PCI devices in guest domains
  750: ----------------------------------
  751: 
  752: The domain0 can give other domains access to selected PCI devices. This
  753: can allow, for example, a non-privileged domain to have access to a
  754: physical network interface or disk controller. However, keep in mind
  755: that giving a domain access to a PCI device most likely will give the
  756: domain read/write access to the whole physical memory, as PCs don't have
  757: an IOMMU to restrict memory access to DMA-capable device. Also, it's not
  758: possible to export ISA devices to non-domain0 domains (which means that
  759: the primary VGA adapter can't be exported. A guest domain trying to
  760: access the VGA registers will panic).
  761: 
  762: This functionality is only available in NetBSD-5.1 (and later) domain0
  763: and domU. If the domain0 is NetBSD, it has to be running Xen 3.1, as
  764: support has not been ported to later versions at this time.
  765: 
  766: For a PCI device to be exported to a domU, is has to be attached to the
  767: `pciback` driver in domain0. Devices passed to the domain0 via the
  768: pciback.hide boot parameter will attach to `pciback` instead of the
  769: usual driver. The list of devices is specified as `(bus:dev.func)`,
  770: where bus and dev are 2-digit hexadecimal numbers, and func a
  771: single-digit number:
  772: 
  773:     pciback.hide=(00:0a.0)(00:06.0)
  774: 
  775: pciback devices should show up in the domain0's boot messages, and the
  776: devices should be listed in the `/kern/xen/pci` directory.
  777: 
  778: PCI devices to be exported to a domU are listed in the `pci` array of
  779: the domU's config file, with the format `'0000:bus:dev.func'`
  780: 
  781:     pci = [ '0000:00:06.0', '0000:00:0a.0' ]
  782: 
  783: In the domU an `xpci` device will show up, to which one or more pci
  784: busses will attach. Then the PCI drivers will attach to PCI busses as
  785: usual. Note that the default NetBSD DOMU kernels do not have `xpci` or
  786: any PCI drivers built in by default; you have to build your own kernel
  787: to use PCI devices in a domU. Here's a kernel config example:
  788: 
  789:     include         "arch/i386/conf/XEN3_DOMU"
  790:     #include         "arch/i386/conf/XENU"           # in NetBSD 3.0
  791: 
  792:     # Add support for PCI busses to the XEN3_DOMU kernel
  793:     xpci* at xenbus ?
  794:     pci* at xpci ?
  795: 
  796:     # Now add PCI and related devices to be used by this domain
  797:     # USB Controller and Devices
  798: 
  799:     # PCI USB controllers
  800:     uhci*   at pci? dev ? function ?        # Universal Host Controller (Intel)
  801: 
  802:     # USB bus support
  803:     usb*    at uhci?
  804: 
  805:     # USB Hubs
  806:     uhub*   at usb?
  807:     uhub*   at uhub? port ? configuration ? interface ?
  808: 
  809:     # USB Mass Storage
  810:     umass*  at uhub? port ? configuration ? interface ?
  811:     wd*     at umass?
  812:     # SCSI controllers
  813:     ahc*    at pci? dev ? function ?        # Adaptec [23]94x, aic78x0 SCSI
  814: 
  815:     # SCSI bus support (for both ahc and umass)
  816:     scsibus* at scsi?
  817: 
  818:     # SCSI devices
  819:     sd*     at scsibus? target ? lun ?      # SCSI disk drives
  820:     cd*     at scsibus? target ? lun ?      # SCSI CD-ROM drives
  821: 
  822: Links and further information
  823: =============================
  824: 
  825: -   The [HowTo on Installing into RAID-1](http://mail-index.NetBSD.org/port-xen/2006/03/01/0010.html)
  826:     explains how to set up booting a dom0 with Xen using grub 
  827:     with NetBSD's RAIDframe.  (This is obsolete with the use of
  828:     NetBSD's native boot.)
  829: -   An example of how to use NetBSD's native bootloader to load
  830:     NetBSD/Xen instead of Grub can be found in the i386/amd64 boot(8)
  831:     and boot.cfg(5) manpages.

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