Annotation of wikisrc/ports/xen/howto.mdwn, revision 1.35

1.5       mspo        1: Introduction
1.13      gdt         2: ============
1.1       mspo        3: 
                      4: [![[Xen
1.7       mspo        5: screenshot]](http://www.netbsd.org/gallery/in-Action/hubertf-xens.png)](../../gallery/in-Action/hubertf-xen.png)
1.1       mspo        6: 
1.12      gdt         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: 
1.29      gdt        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.
1.19      gdt        36: 
1.27      jnemeth    37: At boot, the dom0 kernel is loaded as a module with Xen as the kernel.
1.12      gdt        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
1.24      gdt        44: and running domUs under it (NetBSD and other), and also running NetBSD
                     45: as a domU in a VPS.
1.12      gdt        46: 
1.20      gdt        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: 
1.12      gdt        52: Prerequisites
1.13      gdt        53: -------------
1.12      gdt        54: 
                     55: Installing NetBSD/Xen is not extremely difficult, but it is more
                     56: complex than a normal installation of NetBSD.
1.15      gdt        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.
1.12      gdt        60: 
                     61: This HOWTO presumes a basic familiarity with the Xen system
1.16      gdt        62: architecture.  This HOWTO presumes familiarity with installing NetBSD
                     63: on i386/amd64 hardware and installing software from pkgsrc.
1.27      jnemeth    64: See also the [Xen website](http://www.xenproject.org/).
1.1       mspo       65: 
1.19      gdt        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
1.27      jnemeth    73: [old grub information](/ports/xen/howto-grub/).
1.19      gdt        74: 
1.15      gdt        75: Versions of Xen and NetBSD
                     76: ==========================
                     77: 
1.27      jnemeth    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.
1.15      gdt        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
1.20      gdt        92: receive security patches and should not be used.  Xen 3.1 supports PCI
1.29      gdt        93: passthrough.  Xen 3.1 supports non-PAE on i386.
1.15      gdt        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: 
1.26      gdt       104: Note that NetBSD support is called XEN3.  It works with 3.1 through
                    105: 4.2 because the hypercall interface has been stable.
1.20      gdt       106: 
1.19      gdt       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
1.27      jnemeth   112: called "xl" is provided.  In 4.2 and later, "xl" is preferred.  4.4 is
                    113: the last version that has "xm".
1.19      gdt       114: 
1.15      gdt       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
1.29      gdt       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.
1.15      gdt       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: 
1.18      gdt       130: Architecture
                    131: ------------
                    132: 
1.29      gdt       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.)
1.18      gdt       147: 
1.15      gdt       148: Recommendation
                    149: --------------
                    150: 
1.18      gdt       151: Therefore, this HOWTO recommends running xenkernel42 (and xentools42),
1.30      gdt       152: xl, the NetBSD 6 stable branch, and to use an amd64 kernel as the
                    153: dom0.  Either the i386 or amd64 of NetBSD may be used as domUs.
1.15      gdt       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.
1.19      gdt       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.
1.15      gdt       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: 
1.19      gdt       187: Installation of NetBSD
                    188: ----------------------
1.13      gdt       189: 
1.19      gdt       190: First,
1.27      jnemeth   191: [install NetBSD/amd64](/guide/inst/)
1.19      gdt       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
1.22      gdt       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.
1.19      gdt       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: 
1.27      jnemeth   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.
1.19      gdt       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.)
1.1       mspo      222: 
1.19      gdt       223: Installation of Xen
                    224: -------------------
1.1       mspo      225: 
1.20      gdt       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.
1.1       mspo      262: 
1.28      gdt       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: 
1.21      gdt       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
1.31      gdt       274: started because you still have to configure the dom0 tools.  The
                    275: daemons which should be run vary with Xen version and with whether one
                    276: is using xm or xl.  Note that xend is for supporting "xm", and should
                    277: only be used if you plan on using "xm".  Do NOT enable xend if you
                    278: plan on using "xl" as it will cause problems.
1.21      gdt       279: 
1.31      gdt       280: TODO: Give 3.1 advice (or remove it from pkgsrc).
                    281: 
                    282: For 3.3 (and thus xm), add to rc.conf (but note that you should have
                    283: installed 4.1 or 4.2):
                    284: 
1.32      gdt       285:         xend=YES
                    286:         xenbackendd=YES
1.31      gdt       287: 
1.33      gdt       288: For 4.1 (and thus xm; xl is believed not to work well), add to rc.conf:
1.31      gdt       289: 
                    290:         xend=YES
                    291:         xencommons=YES
                    292: 
                    293: TODO: Explain why if xm is preferred on 4.1, rc.d/xendomains has xl.
1.33      gdt       294: Or fix the package.
1.31      gdt       295: 
1.33      gdt       296: For 4.2 with xm, add to rc.conf
                    297: 
                    298:         xend=YES
                    299:         xencommons=YES
                    300: 
                    301: For 4.2 with xl (preferred), add to rc.conf:
1.31      gdt       302: 
                    303:         TODO: explain if there is a xend replacement
                    304:         xencommons=YES
                    305: 
                    306: TODO: Recommend for/against xen-watchdog.
1.27      jnemeth   307: 
1.33      gdt       308: After you have configured the daemons and rebooted, run the following
                    309: to inspect Xen's boot messages, available resources, and running
                    310: domains:
1.34      gdt       311: 
1.33      gdt       312:         xm dmesg
1.35    ! gdt       313:         xm info
        !           314:         xm list
1.33      gdt       315: 
1.15      gdt       316: Updating NetBSD in a dom0
                    317: -------------------------
                    318: 
                    319: This is just like updating NetBSD on bare hardware, assuming the new
                    320: version supports the version of Xen you are running.  Generally, one
                    321: replaces the kernel and reboots, and then overlays userland binaries
                    322: and adjusts /etc.
                    323: 
                    324: Note that one must update both the non-Xen kernel typically used for
                    325: rescue purposes and the DOM0 kernel used with Xen.
                    326: 
1.22      gdt       327: To convert from grub to /boot, install an mbr bootblock with fdisk,
                    328: bootxx_ with installboot, /boot and /boot.cfg.  This really should be
                    329: no different than completely reinstalling boot blocks on a non-Xen
                    330: system.
                    331: 
1.15      gdt       332: Updating Xen versions
                    333: ---------------------
                    334: 
1.21      gdt       335: Updating Xen is conceptually not difficult, but can run into all the
                    336: issues found when installing Xen.  Assuming migration from 4.1 to 4.2,
                    337: remove the xenkernel41 and xentools41 packages and install the
                    338: xenkernel42 and xentools42 packages.  Copy the 4.2 xen.gz to /.
                    339: 
                    340: Ensure that the contents of /etc/rc.d/xen* are correct.  Enable the
                    341: correct set of daemons.  Ensure that the domU config files are valid
                    342: for the new version.
1.15      gdt       343: 
1.28      gdt       344: 
                    345: Unprivileged domains (domU)
                    346: ===========================
                    347: 
                    348: This section describes general concepts about domUs.  It does not
1.33      gdt       349: address specific domU operating systems or how to install them.  The
                    350: config files for domUs are typically in /usr/pkg/etc/xen, and are
                    351: typically named so that the file anme, domU name and the domU's host
                    352: name match.
                    353: 
                    354: The domU is provided with cpu and memory by Xen, configured by the
                    355: dom0.  The domU is provided with disk and network by the dom0,
                    356: mediated by Xen, and configured in the dom0.
                    357: 
                    358: Entropy in domUs can be an issue; physical disks and network are on
                    359: the dom0.  NetBSD's /dev/random system works, but is often challenged.
                    360: 
                    361: CPU and memory
                    362: --------------
                    363: 
                    364: A domain is provided with some number of vcpus, less than the
                    365: number of cpus seen by the hypervisor.  For a dom0, this is controlled
                    366: by the boot argument "dom0_max_vcpus=1".  For a domU, it is controlled
                    367: from the config file.
                    368: 
                    369: A domain is provided with memory, In the straightforward case, the sum
                    370: of the the memory allocated to the dom0 and all domUs must be less
                    371: than the available memory.
                    372: 
                    373: Xen also provides a "balloon" driver, which can be used to let domains
                    374: use more memory temporarily.  TODO: Explain better, and explain how
                    375: well it works with NetBSD.
1.28      gdt       376: 
                    377: Virtual disks
                    378: -------------
                    379: 
1.33      gdt       380: With the file/vnd style, typically one creates a directory,
                    381: e.g. /u0/xen, on a disk large enough to hold virtual disks for all
                    382: domUs.  Then, for each domU disk, one writes zeros to a file that then
                    383: serves to hold the virtual disk's bits; a suggested name is foo-xbd0
                    384: for the first virtual disk for the domU called foo.  Writing zeros to
                    385: the file serves two purposes.  One is that preallocating the contents
                    386: improves performance.  The other is that vnd on sparse files has
                    387: failed to work.  TODO: give working/notworking NetBSD versions for
                    388: sparse vnd.  Note that the use of file/vnd for Xen is not really
                    389: different than creating a file-backed virtual disk for some other
                    390: purpose, except that xentools handles the vnconfig commands.
                    391: 
                    392: With the lvm style, one creates logical devices.  They are then used
                    393: similarly to vnds.
1.28      gdt       394: 
                    395: Virtual Networking
                    396: ------------------
                    397: 
                    398: TODO: explain xvif concept, and that it's general.
                    399: 
                    400: There are two normal styles: bridging and NAT.
                    401: 
                    402: With bridging, the domU perceives itself to be on the same network as
                    403: the dom0.  For server virtualization, this is usually best.
                    404: 
                    405: With NAT, the domU perceives itself to be behind a NAT running on the
                    406: dom0.  This is often appropriate when running Xen on a workstation.
                    407: 
                    408: One can construct arbitrary other configurations, but there is no
                    409: script support.
                    410: 
1.33      gdt       411: Sizing domains
                    412: --------------
                    413: 
                    414: Modern x86 hardware has vast amounts of resources.  However, many
                    415: virtual servers can function just fine on far less.  A system with
                    416: 256M of RAM and a 4G disk can be a reasonable choice.  Note that it is
                    417: far easier to adjust virtual resources than physical ones.  For
                    418: memory, it's just a config file edit and a reboot.  For disk, one can
                    419: create a new file and vnconfig it (or lvm), and then dump/restore,
                    420: just like updating physical disks, but without having to be there and
                    421: without those pesky connectors.
                    422: 
1.28      gdt       423: Config files
                    424: ------------
                    425: 
                    426: TODO: give example config files.   Use both lvm and vnd.
                    427: 
                    428: TODO: explain the mess with 3 arguments for disks and how to cope (0x1).
                    429: 
                    430: Starting domains
                    431: ----------------
                    432: 
                    433: TODO: Explain "xm start" and "xl start".  Explain rc.d/xendomains.
                    434: 
                    435: TODO: Explain why 4.1 rc.d/xendomains has xl, when one should use xm
                    436: on 4.1.
                    437: 
                    438: Creating specific unprivileged domains (domU)
                    439: =============================================
1.14      gdt       440: 
                    441: Creating domUs is almost entirely independent of operating system.  We
                    442: first explain NetBSD, and then differences for Linux and Solaris.
                    443: 
                    444: Creating an unprivileged NetBSD domain (domU)
                    445: ---------------------------------------------
1.1       mspo      446: 
                    447: Once you have *domain0* running, you need to start the xen tool daemon
1.5       mspo      448: (`/usr/pkg/share/examples/rc.d/xend start`) and the xen backend daemon
                    449: (`/usr/pkg/share/examples/rc.d/xenbackendd start` for Xen3\*,
                    450: `/usr/pkg/share/examples/rc.d/xencommons start` for Xen4.\*). Make sure
                    451: that `/dev/xencons` and `/dev/xenevt` exist before starting `xend`. You
                    452: can create them with this command:
1.1       mspo      453: 
1.3       mspo      454:     # cd /dev && sh MAKEDEV xen
1.1       mspo      455: 
1.5       mspo      456: xend will write logs to `/var/log/xend.log` and
                    457: `/var/log/xend-debug.log`. You can then control xen with the xm tool.
                    458: 'xm list' will show something like:
1.1       mspo      459: 
1.3       mspo      460:     # xm list
                    461:     Name              Id  Mem(MB)  CPU  State  Time(s)  Console
                    462:     Domain-0           0       64    0  r----     58.1
1.1       mspo      463: 
                    464: 'xm create' allows you to create a new domain. It uses a config file in
                    465: PKG\_SYSCONFDIR for its parameters. By default, this file will be in
1.5       mspo      466: `/usr/pkg/etc/xen/`. On creation, a kernel has to be specified, which
                    467: will be executed in the new domain (this kernel is in the *domain0* file
                    468: system, not on the new domain virtual disk; but please note, you should
                    469: install the same kernel into *domainU* as `/netbsd` in order to make
1.27      jnemeth   470: your system tools, like savecore(8), work). A suitable kernel is
1.5       mspo      471: provided as part of the i386 and amd64 binary sets: XEN3\_DOMU.
1.1       mspo      472: 
                    473: Here is an /usr/pkg/etc/xen/nbsd example config file:
                    474: 
1.3       mspo      475:     #  -*- mode: python; -*-
                    476:     #============================================================================
                    477:     # Python defaults setup for 'xm create'.
                    478:     # Edit this file to reflect the configuration of your system.
                    479:     #============================================================================
1.5       mspo      480: 
1.3       mspo      481:     #----------------------------------------------------------------------------
                    482:     # Kernel image file. This kernel will be loaded in the new domain.
                    483:     kernel = "/home/bouyer/netbsd-XEN3_DOMU"
                    484:     #kernel = "/home/bouyer/netbsd-INSTALL_XEN3_DOMU"
1.5       mspo      485: 
1.3       mspo      486:     # Memory allocation (in megabytes) for the new domain.
                    487:     memory = 128
1.5       mspo      488: 
1.3       mspo      489:     # A handy name for your new domain. This will appear in 'xm list',
                    490:     # and you can use this as parameters for xm in place of the domain
                    491:     # number. All domains must have different names.
                    492:     #
                    493:     name = "nbsd"
1.5       mspo      494: 
1.3       mspo      495:     # The number of virtual CPUs this domain has.
                    496:     #
                    497:     vcpus = 1
1.5       mspo      498: 
1.3       mspo      499:     #----------------------------------------------------------------------------
                    500:     # Define network interfaces for the new domain.
1.5       mspo      501: 
1.3       mspo      502:     # Number of network interfaces (must be at least 1). Default is 1.
                    503:     nics = 1
1.5       mspo      504: 
1.3       mspo      505:     # Define MAC and/or bridge for the network interfaces.
                    506:     #
                    507:     # The MAC address specified in ``mac'' is the one used for the interface
                    508:     # in the new domain. The interface in domain0 will use this address XOR'd
                    509:     # with 00:00:00:01:00:00 (i.e. aa:00:00:51:02:f0 in our example). Random
                    510:     # MACs are assigned if not given.
                    511:     #
                    512:     # ``bridge'' is a required parameter, which will be passed to the
                    513:     # vif-script called by xend(8) when a new domain is created to configure
                    514:     # the new xvif interface in domain0.
                    515:     #
                    516:     # In this example, the xvif is added to bridge0, which should have been
                    517:     # set up prior to the new domain being created -- either in the
                    518:     # ``network'' script or using a /etc/ifconfig.bridge0 file.
                    519:     #
                    520:     vif = [ 'mac=aa:00:00:50:02:f0, bridge=bridge0' ]
1.5       mspo      521: 
1.3       mspo      522:     #----------------------------------------------------------------------------
                    523:     # Define the disk devices you want the domain to have access to, and
                    524:     # what you want them accessible as.
                    525:     #
                    526:     # Each disk entry is of the form:
                    527:     #
1.5       mspo      528:     #   phy:DEV,VDEV,MODE
1.3       mspo      529:     #
                    530:     # where DEV is the device, VDEV is the device name the domain will see,
                    531:     # and MODE is r for read-only, w for read-write.  You can also create
                    532:     # file-backed domains using disk entries of the form:
                    533:     #
1.5       mspo      534:     #   file:PATH,VDEV,MODE
1.3       mspo      535:     #
                    536:     # where PATH is the path to the file used as the virtual disk, and VDEV
                    537:     # and MODE have the same meaning as for ``phy'' devices.
                    538:     #
                    539:     # VDEV doesn't really matter for a NetBSD guest OS (it's just used as an index),
                    540:     # but it does for Linux.
                    541:     # Worse, the device has to exist in /dev/ of domain0, because xm will
                    542:     # try to stat() it. This means that in order to load a Linux guest OS
                    543:     # from a NetBSD domain0, you'll have to create /dev/hda1, /dev/hda2, ...
                    544:     # on domain0, with the major/minor from Linux :(
                    545:     # Alternatively it's possible to specify the device number in hex,
                    546:     # e.g. 0x301 for /dev/hda1, 0x302 for /dev/hda2, etc ...
1.5       mspo      547: 
1.3       mspo      548:     disk = [ 'phy:/dev/wd0e,0x1,w' ]
                    549:     #disk = [ 'file:/var/xen/nbsd-disk,0x01,w' ]
                    550:     #disk = [ 'file:/var/xen/nbsd-disk,0x301,w' ]
1.5       mspo      551: 
1.3       mspo      552:     #----------------------------------------------------------------------------
                    553:     # Set the kernel command line for the new domain.
1.5       mspo      554: 
1.3       mspo      555:     # Set root device. This one does matter for NetBSD
                    556:     root = "xbd0"
                    557:     # extra parameters passed to the kernel
                    558:     # this is where you can set boot flags like -s, -a, etc ...
                    559:     #extra = ""
1.5       mspo      560: 
1.3       mspo      561:     #----------------------------------------------------------------------------
                    562:     # Set according to whether you want the domain restarted when it exits.
                    563:     # The default is False.
                    564:     #autorestart = True
1.5       mspo      565: 
1.3       mspo      566:     # end of nbsd config file ====================================================
1.1       mspo      567: 
                    568: When a new domain is created, xen calls the
1.5       mspo      569: `/usr/pkg/etc/xen/vif-bridge` script for each virtual network interface
                    570: created in *domain0*. This can be used to automatically configure the
                    571: xvif?.? interfaces in *domain0*. In our example, these will be bridged
                    572: with the bridge0 device in *domain0*, but the bridge has to exist first.
                    573: To do this, create the file `/etc/ifconfig.bridge0` and make it look
                    574: like this:
1.1       mspo      575: 
1.3       mspo      576:     create
                    577:     !brconfig $int add ex0 up
1.1       mspo      578: 
1.5       mspo      579: (replace `ex0` with the name of your physical interface). Then bridge0
1.27      jnemeth   580: will be created on boot. See the bridge(4) man page for details.
1.1       mspo      581: 
1.5       mspo      582: So, here is a suitable `/usr/pkg/etc/xen/vif-bridge` for xvif?.? (a
                    583: working vif-bridge is also provided with xentools20) configuring:
1.1       mspo      584: 
1.5       mspo      585:     #!/bin/sh
1.3       mspo      586:     #============================================================================
1.35    ! gdt       587:     # $NetBSD: howto.mdwn,v 1.34 2014/12/24 15:55:32 gdt Exp $
1.3       mspo      588:     #
                    589:     # /usr/pkg/etc/xen/vif-bridge
                    590:     #
                    591:     # Script for configuring a vif in bridged mode with a dom0 interface.
                    592:     # The xend(8) daemon calls a vif script when bringing a vif up or down.
                    593:     # The script name to use is defined in /usr/pkg/etc/xen/xend-config.sxp
                    594:     # in the ``vif-script'' field.
                    595:     #
                    596:     # Usage: vif-bridge up|down [var=value ...]
                    597:     #
                    598:     # Actions:
1.5       mspo      599:     #    up     Adds the vif interface to the bridge.
                    600:     #    down   Removes the vif interface from the bridge.
1.3       mspo      601:     #
                    602:     # Variables:
1.5       mspo      603:     #    domain name of the domain the interface is on (required).
                    604:     #    vifq   vif interface name (required).
                    605:     #    mac    vif MAC address (required).
                    606:     #    bridge bridge to add the vif to (required).
1.3       mspo      607:     #
                    608:     # Example invocation:
                    609:     #
                    610:     # vif-bridge up domain=VM1 vif=xvif1.0 mac="ee:14:01:d0:ec:af" bridge=bridge0
                    611:     #
                    612:     #============================================================================
1.5       mspo      613: 
1.3       mspo      614:     # Exit if anything goes wrong
                    615:     set -e
1.5       mspo      616: 
1.3       mspo      617:     echo "vif-bridge $*"
1.5       mspo      618: 
1.3       mspo      619:     # Operation name.
                    620:     OP=$1; shift
1.5       mspo      621: 
1.3       mspo      622:     # Pull variables in args into environment
                    623:     for arg ; do export "${arg}" ; done
1.5       mspo      624: 
1.3       mspo      625:     # Required parameters. Fail if not set.
                    626:     domain=${domain:?}
                    627:     vif=${vif:?}
                    628:     mac=${mac:?}
                    629:     bridge=${bridge:?}
1.5       mspo      630: 
1.3       mspo      631:     # Optional parameters. Set defaults.
                    632:     ip=${ip:-''}   # default to null (do nothing)
1.5       mspo      633: 
1.3       mspo      634:     # Are we going up or down?
                    635:     case $OP in
1.5       mspo      636:     up) brcmd='add' ;;
1.3       mspo      637:     down)   brcmd='delete' ;;
                    638:     *)
1.5       mspo      639:         echo 'Invalid command: ' $OP
                    640:         echo 'Valid commands are: up, down'
                    641:         exit 1
                    642:         ;;
1.3       mspo      643:     esac
1.5       mspo      644: 
1.3       mspo      645:     # Don't do anything if the bridge is "null".
                    646:     if [ "${bridge}" = "null" ] ; then
1.5       mspo      647:         exit
1.3       mspo      648:     fi
1.5       mspo      649: 
1.3       mspo      650:     # Don't do anything if the bridge doesn't exist.
                    651:     if ! ifconfig -l | grep "${bridge}" >/dev/null; then
1.5       mspo      652:         exit
1.3       mspo      653:     fi
1.5       mspo      654: 
1.3       mspo      655:     # Add/remove vif to/from bridge.
                    656:     ifconfig x${vif} $OP
                    657:     brconfig ${bridge} ${brcmd} x${vif}
1.1       mspo      658: 
                    659: Now, running
                    660: 
1.3       mspo      661:     xm create -c /usr/pkg/etc/xen/nbsd
1.1       mspo      662: 
1.5       mspo      663: should create a domain and load a NetBSD kernel in it. (Note: `-c`
                    664: causes xm to connect to the domain's console once created.) The kernel
                    665: will try to find its root file system on xbd0 (i.e., wd0e) which hasn't
                    666: been created yet. wd0e will be seen as a disk device in the new domain,
                    667: so it will be 'sub-partitioned'. We could attach a ccd to wd0e in
                    668: *domain0* and partition it, newfs and extract the NetBSD/i386 or amd64
                    669: tarballs there, but there's an easier way: load the
                    670: `netbsd-INSTALL_XEN3_DOMU` kernel provided in the NetBSD binary sets.
                    671: Like other install kernels, it contains a ramdisk with sysinst, so you
                    672: can install NetBSD using sysinst on your new domain.
1.1       mspo      673: 
                    674: If you want to install NetBSD/Xen with a CDROM image, the following line
1.5       mspo      675: should be used in the `/usr/pkg/etc/xen/nbsd` file:
1.1       mspo      676: 
1.3       mspo      677:     disk = [ 'phy:/dev/wd0e,0x1,w', 'phy:/dev/cd0a,0x2,r' ]
1.1       mspo      678: 
                    679: After booting the domain, the option to install via CDROM may be
1.5       mspo      680: selected. The CDROM device should be changed to `xbd1d`.
1.1       mspo      681: 
1.5       mspo      682: Once done installing, `halt -p` the new domain (don't reboot or halt, it
                    683: would reload the INSTALL\_XEN3\_DOMU kernel even if you changed the
1.1       mspo      684: config file), switch the config file back to the XEN3\_DOMU kernel, and
1.5       mspo      685: start the new domain again. Now it should be able to use `root on xbd0a`
                    686: and you should have a second, functional NetBSD system on your xen
                    687: installation.
1.1       mspo      688: 
                    689: When the new domain is booting you'll see some warnings about *wscons*
                    690: and the pseudo-terminals. These can be fixed by editing the files
1.5       mspo      691: `/etc/ttys` and `/etc/wscons.conf`. You must disable all terminals in
                    692: `/etc/ttys`, except *console*, like this:
1.1       mspo      693: 
1.3       mspo      694:     console "/usr/libexec/getty Pc"         vt100   on secure
                    695:     ttyE0   "/usr/libexec/getty Pc"         vt220   off secure
                    696:     ttyE1   "/usr/libexec/getty Pc"         vt220   off secure
                    697:     ttyE2   "/usr/libexec/getty Pc"         vt220   off secure
                    698:     ttyE3   "/usr/libexec/getty Pc"         vt220   off secure
1.1       mspo      699: 
1.5       mspo      700: Finally, all screens must be commented out from `/etc/wscons.conf`.
1.1       mspo      701: 
                    702: It is also desirable to add
                    703: 
1.3       mspo      704:     powerd=YES
1.1       mspo      705: 
1.5       mspo      706: in rc.conf. This way, the domain will be properly shut down if
                    707: `xm shutdown -R` or `xm shutdown -H` is used on the domain0.
1.1       mspo      708: 
                    709: Your domain should be now ready to work, enjoy.
                    710: 
1.14      gdt       711: Creating an unprivileged Linux domain (domU)
1.5       mspo      712: --------------------------------------------
1.1       mspo      713: 
                    714: Creating unprivileged Linux domains isn't much different from
                    715: unprivileged NetBSD domains, but there are some details to know.
                    716: 
                    717: First, the second parameter passed to the disk declaration (the '0x1' in
                    718: the example below)
                    719: 
1.3       mspo      720:     disk = [ 'phy:/dev/wd0e,0x1,w' ]
1.1       mspo      721: 
                    722: does matter to Linux. It wants a Linux device number here (e.g. 0x300
                    723: for hda). Linux builds device numbers as: (major \<\< 8 + minor). So,
                    724: hda1 which has major 3 and minor 1 on a Linux system will have device
                    725: number 0x301. Alternatively, devices names can be used (hda, hdb, ...)
                    726: as xentools has a table to map these names to devices numbers. To export
                    727: a partition to a Linux guest we can use:
                    728: 
1.3       mspo      729:     disk = [ 'phy:/dev/wd0e,0x300,w' ]
                    730:     root = "/dev/hda1 ro"
1.1       mspo      731: 
                    732: and it will appear as /dev/hda on the Linux system, and be used as root
                    733: partition.
                    734: 
                    735: To install the Linux system on the partition to be exported to the guest
                    736: domain, the following method can be used: install sysutils/e2fsprogs
                    737: from pkgsrc. Use mke2fs to format the partition that will be the root
                    738: partition of your Linux domain, and mount it. Then copy the files from a
1.5       mspo      739: working Linux system, make adjustments in `/etc` (fstab, network
                    740: config). It should also be possible to extract binary packages such as
                    741: .rpm or .deb directly to the mounted partition using the appropriate
                    742: tool, possibly running under NetBSD's Linux emulation. Once the
                    743: filesystem has been populated, umount it. If desirable, the filesystem
                    744: can be converted to ext3 using tune2fs -j. It should now be possible to
                    745: boot the Linux guest domain, using one of the vmlinuz-\*-xenU kernels
                    746: available in the Xen binary distribution.
1.1       mspo      747: 
                    748: To get the linux console right, you need to add:
                    749: 
1.3       mspo      750:     extra = "xencons=tty1"
1.1       mspo      751: 
                    752: to your configuration since not all linux distributions auto-attach a
                    753: tty to the xen console.
                    754: 
1.14      gdt       755: Creating an unprivileged Solaris domain (domU)
1.5       mspo      756: ----------------------------------------------
1.1       mspo      757: 
                    758: Download an Opensolaris [release](http://opensolaris.org/os/downloads/)
                    759: or [development snapshot](http://genunix.org/) DVD image. Attach the DVD
1.5       mspo      760: image to a MAN.VND.4 device. Copy the kernel and ramdisk filesystem
                    761: image to your dom0 filesystem.
1.1       mspo      762: 
1.3       mspo      763:     dom0# mkdir /root/solaris
                    764:     dom0# vnconfig vnd0 osol-1002-124-x86.iso
                    765:     dom0# mount /dev/vnd0a /mnt
1.5       mspo      766: 
1.3       mspo      767:     ## for a 64-bit guest
                    768:     dom0# cp /mnt/boot/amd64/x86.microroot /root/solaris
                    769:     dom0# cp /mnt/platform/i86xpv/kernel/amd64/unix /root/solaris
1.5       mspo      770: 
1.3       mspo      771:     ## for a 32-bit guest
                    772:     dom0# cp /mnt/boot/x86.microroot /root/solaris
                    773:     dom0# cp /mnt/platform/i86xpv/kernel/unix /root/solaris
1.5       mspo      774: 
1.3       mspo      775:     dom0# umount /mnt
1.5       mspo      776:           
                    777: 
                    778: Keep the MAN.VND.4 configured. For some reason the boot process stalls
                    779: unless the DVD image is attached to the guest as a "phy" device. Create
                    780: an initial configuration file with the following contents. Substitute
                    781: */dev/wd0k* with an empty partition at least 8 GB large.
1.1       mspo      782: 
1.4       mspo      783:     memory = 640
                    784:     name = 'solaris'
                    785:     disk = [ 'phy:/dev/wd0k,0,w' ]
                    786:     disk += [ 'phy:/dev/vnd0d,6:cdrom,r' ]
                    787:     vif = [ 'bridge=bridge0' ]
                    788:     kernel = '/root/solaris/unix'
                    789:     ramdisk = '/root/solaris/x86.microroot'
                    790:     # for a 64-bit guest
                    791:     extra = '/platform/i86xpv/kernel/amd64/unix - nowin -B install_media=cdrom'
                    792:     # for a 32-bit guest
                    793:     #extra = '/platform/i86xpv/kernel/unix - nowin -B install_media=cdrom'
1.5       mspo      794:           
                    795: 
1.1       mspo      796: Start the guest.
                    797: 
1.4       mspo      798:     dom0# xm create -c solaris.cfg
                    799:     Started domain solaris
                    800:                           v3.3.2 chgset 'unavailable'
                    801:     SunOS Release 5.11 Version snv_124 64-bit
                    802:     Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.
                    803:     Use is subject to license terms.
                    804:     Hostname: opensolaris
                    805:     Remounting root read/write
                    806:     Probing for device nodes ...
                    807:     WARNING: emlxs: ddi_modopen drv/fct failed: err 2
                    808:     Preparing live image for use
                    809:     Done mounting Live image
1.5       mspo      810:           
1.1       mspo      811: 
                    812: Make sure the network is configured. Note that it can take a minute for
                    813: the xnf0 interface to appear.
                    814: 
1.4       mspo      815:     opensolaris console login: jack
                    816:     Password: jack
                    817:     Sun Microsystems Inc.   SunOS 5.11      snv_124 November 2008
                    818:     jack@opensolaris:~$ pfexec sh
                    819:     sh-3.2# ifconfig -a
                    820:     sh-3.2# exit
1.5       mspo      821:           
1.1       mspo      822: 
                    823: Set a password for VNC and start the VNC server which provides the X11
                    824: display where the installation program runs.
                    825: 
1.4       mspo      826:     jack@opensolaris:~$ vncpasswd
                    827:     Password: solaris
                    828:     Verify: solaris
                    829:     jack@opensolaris:~$ cp .Xclients .vnc/xstartup
                    830:     jack@opensolaris:~$ vncserver :1
1.5       mspo      831:           
1.1       mspo      832: 
1.5       mspo      833: From a remote machine connect to the VNC server. Use `ifconfig xnf0` on
                    834: the guest to find the correct IP address to use.
1.1       mspo      835: 
1.4       mspo      836:     remote$ vncviewer 172.18.2.99:1
1.5       mspo      837:           
1.1       mspo      838: 
                    839: It is also possible to launch the installation on a remote X11 display.
                    840: 
1.4       mspo      841:     jack@opensolaris:~$ export DISPLAY=172.18.1.1:0
                    842:     jack@opensolaris:~$ pfexec gui-install
1.5       mspo      843:            
1.1       mspo      844: 
                    845: After the GUI installation is complete you will be asked to reboot.
                    846: Before that you need to determine the ZFS ID for the new boot filesystem
                    847: and update the configuration file accordingly. Return to the guest
                    848: console.
                    849: 
1.4       mspo      850:     jack@opensolaris:~$ pfexec zdb -vvv rpool | grep bootfs
                    851:                     bootfs = 43
                    852:     ^C
                    853:     jack@opensolaris:~$
1.5       mspo      854:            
1.1       mspo      855: 
                    856: The final configuration file should look like this. Note in particular
                    857: the last line.
                    858: 
1.4       mspo      859:     memory = 640
                    860:     name = 'solaris'
                    861:     disk = [ 'phy:/dev/wd0k,0,w' ]
                    862:     vif = [ 'bridge=bridge0' ]
                    863:     kernel = '/root/solaris/unix'
                    864:     ramdisk = '/root/solaris/x86.microroot'
                    865:     extra = '/platform/i86xpv/kernel/amd64/unix -B zfs-bootfs=rpool/43,bootpath="/xpvd/xdf@0:a"'
1.5       mspo      866:            
1.1       mspo      867: 
                    868: Restart the guest to verify it works correctly.
                    869: 
1.4       mspo      870:     dom0# xm destroy solaris
                    871:     dom0# xm create -c solaris.cfg
                    872:     Using config file "./solaris.cfg".
                    873:     v3.3.2 chgset 'unavailable'
                    874:     Started domain solaris
                    875:     SunOS Release 5.11 Version snv_124 64-bit
                    876:     Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.
                    877:     Use is subject to license terms.
                    878:     WARNING: emlxs: ddi_modopen drv/fct failed: err 2
                    879:     Hostname: osol
                    880:     Configuring devices.
                    881:     Loading smf(5) service descriptions: 160/160
                    882:     svccfg import warnings. See /var/svc/log/system-manifest-import:default.log .
                    883:     Reading ZFS config: done.
                    884:     Mounting ZFS filesystems: (6/6)
                    885:     Creating new rsa public/private host key pair
                    886:     Creating new dsa public/private host key pair
1.5       mspo      887: 
1.4       mspo      888:     osol console login:
1.5       mspo      889:            
1.1       mspo      890: 
                    891: Using PCI devices in guest domains
1.14      gdt       892: ----------------------------------
1.1       mspo      893: 
                    894: The domain0 can give other domains access to selected PCI devices. This
                    895: can allow, for example, a non-privileged domain to have access to a
                    896: physical network interface or disk controller. However, keep in mind
                    897: that giving a domain access to a PCI device most likely will give the
                    898: domain read/write access to the whole physical memory, as PCs don't have
                    899: an IOMMU to restrict memory access to DMA-capable device. Also, it's not
                    900: possible to export ISA devices to non-domain0 domains (which means that
                    901: the primary VGA adapter can't be exported. A guest domain trying to
                    902: access the VGA registers will panic).
                    903: 
                    904: This functionality is only available in NetBSD-5.1 (and later) domain0
                    905: and domU. If the domain0 is NetBSD, it has to be running Xen 3.1, as
                    906: support has not been ported to later versions at this time.
                    907: 
                    908: For a PCI device to be exported to a domU, is has to be attached to the
1.5       mspo      909: `pciback` driver in domain0. Devices passed to the domain0 via the
                    910: pciback.hide boot parameter will attach to `pciback` instead of the
                    911: usual driver. The list of devices is specified as `(bus:dev.func)`,
                    912: where bus and dev are 2-digit hexadecimal numbers, and func a
                    913: single-digit number:
1.1       mspo      914: 
1.4       mspo      915:     pciback.hide=(00:0a.0)(00:06.0)
1.1       mspo      916: 
                    917: pciback devices should show up in the domain0's boot messages, and the
1.5       mspo      918: devices should be listed in the `/kern/xen/pci` directory.
1.1       mspo      919: 
1.5       mspo      920: PCI devices to be exported to a domU are listed in the `pci` array of
                    921: the domU's config file, with the format `'0000:bus:dev.func'`
1.1       mspo      922: 
1.4       mspo      923:     pci = [ '0000:00:06.0', '0000:00:0a.0' ]
1.1       mspo      924: 
1.5       mspo      925: In the domU an `xpci` device will show up, to which one or more pci
                    926: busses will attach. Then the PCI drivers will attach to PCI busses as
                    927: usual. Note that the default NetBSD DOMU kernels do not have `xpci` or
                    928: any PCI drivers built in by default; you have to build your own kernel
                    929: to use PCI devices in a domU. Here's a kernel config example:
1.1       mspo      930: 
1.4       mspo      931:     include         "arch/i386/conf/XEN3_DOMU"
                    932:     #include         "arch/i386/conf/XENU"           # in NetBSD 3.0
1.5       mspo      933: 
1.4       mspo      934:     # Add support for PCI busses to the XEN3_DOMU kernel
                    935:     xpci* at xenbus ?
                    936:     pci* at xpci ?
1.5       mspo      937: 
1.4       mspo      938:     # Now add PCI and related devices to be used by this domain
                    939:     # USB Controller and Devices
1.5       mspo      940: 
1.4       mspo      941:     # PCI USB controllers
                    942:     uhci*   at pci? dev ? function ?        # Universal Host Controller (Intel)
1.5       mspo      943: 
1.4       mspo      944:     # USB bus support
                    945:     usb*    at uhci?
1.5       mspo      946: 
1.4       mspo      947:     # USB Hubs
                    948:     uhub*   at usb?
                    949:     uhub*   at uhub? port ? configuration ? interface ?
1.5       mspo      950: 
1.4       mspo      951:     # USB Mass Storage
                    952:     umass*  at uhub? port ? configuration ? interface ?
                    953:     wd*     at umass?
                    954:     # SCSI controllers
                    955:     ahc*    at pci? dev ? function ?        # Adaptec [23]94x, aic78x0 SCSI
1.5       mspo      956: 
1.4       mspo      957:     # SCSI bus support (for both ahc and umass)
                    958:     scsibus* at scsi?
1.5       mspo      959: 
1.4       mspo      960:     # SCSI devices
                    961:     sd*     at scsibus? target ? lun ?      # SCSI disk drives
                    962:     cd*     at scsibus? target ? lun ?      # SCSI CD-ROM drives
1.1       mspo      963: 
                    964: 
1.28      gdt       965: NetBSD as a domU in a VPS
                    966: =========================
                    967: 
                    968: The bulk of the HOWTO is about using NetBSD as a dom0 on your own
                    969: hardware.  This section explains how to deal with Xen in a domU as a
                    970: virtual private server where you do not control or have access to the
                    971: dom0.
                    972: 
                    973: TODO: Perhaps reference panix, prmgr, amazon as interesting examples.
                    974: 
                    975: TODO: Somewhere, discuss pvgrub and py-grub to load the domU kernel
                    976: from the domU filesystem.

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