Annotation of wikisrc/ports/xen/howto.mdwn, revision 1.48

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: 
1.36      gdt       155: Build problems
                    156: --------------
                    157: 
                    158: Ideally, all versions of Xen in pkgsrc would build on all versions of
                    159: NetBSD on both i386 and amd64.  However, that isn't the case.  Besides
                    160: aging code and aging compilers, qemu (included in xentools for HVM
                    161: support) is difficult to build.  The following are known to fail:
                    162: 
                    163:         xenkernel3 netbsd-6 i386
                    164:         xentools42 netbsd-6 i386 
                    165: 
                    166: The following are known to work:
                    167: 
                    168:         xenkernel41 netbsd-5 amd64
                    169:         xentools41 netbsd-5 amd64
                    170:         xenkernel41 netbsd-6 i386
                    171:         xentools41 netbsd-6 i386
                    172: 
1.15      gdt       173: NetBSD as a dom0
                    174: ================
                    175: 
                    176: NetBSD can be used as a dom0 and works very well.  The following
                    177: sections address installation, updating NetBSD, and updating Xen.
1.19      gdt       178: Note that it doesn't make sense to talk about installing a dom0 OS
                    179: without also installing Xen itself.  We first address installing
                    180: NetBSD, which is not yet a dom0, and then adding Xen, pivoting the
                    181: NetBSD install to a dom0 install by just changing the kernel and boot
                    182: configuration.
1.15      gdt       183: 
1.45      gdt       184: For experimenting with Xen, a machine with as little as 1G of RAM and
                    185: 100G of disk can work.  For running many domUs in productions, far
                    186: more will be needed.
                    187: 
1.15      gdt       188: Styles of dom0 operation
                    189: ------------------------
                    190: 
                    191: There are two basic ways to use Xen.  The traditional method is for
                    192: the dom0 to do absolutely nothing other than providing support to some
                    193: number of domUs.  Such a system was probably installed for the sole
                    194: purpose of hosting domUs, and sits in a server room on a UPS.
                    195: 
                    196: The other way is to put Xen under a normal-usage computer, so that the
                    197: dom0 is what the computer would have been without Xen, perhaps a
                    198: desktop or laptop.  Then, one can run domUs at will.  Purists will
                    199: deride this as less secure than the previous approach, and for a
                    200: computer whose purpose is to run domUs, they are right.  But Xen and a
                    201: dom0 (without domUs) is not meaingfully less secure than the same
                    202: things running without Xen.  One can boot Xen or boot regular NetBSD
                    203: alternately with little problems, simply refraining from starting the
                    204: Xen daemons when not running Xen.
                    205: 
                    206: Note that NetBSD as dom0 does not support multiple CPUs.  This will
                    207: limit the performance of the Xen/dom0 workstation approach.
                    208: 
1.19      gdt       209: Installation of NetBSD
                    210: ----------------------
1.13      gdt       211: 
1.19      gdt       212: First,
1.27      jnemeth   213: [install NetBSD/amd64](/guide/inst/)
1.19      gdt       214: just as you would if you were not using Xen.
                    215: However, the partitioning approach is very important.
                    216: 
                    217: If you want to use RAIDframe for the dom0, there are no special issues
                    218: for Xen.  Typically one provides RAID storage for the dom0, and the
1.22      gdt       219: domU systems are unaware of RAID.  The 2nd-stage loader bootxx_* skips
                    220: over a RAID1 header to find /boot from a filesystem within a RAID
                    221: partition; this is no different when booting Xen.
1.19      gdt       222: 
                    223: There are 4 styles of providing backing storage for the virtual disks
                    224: used by domUs: raw partitions, LVM, file-backed vnd(4), and SAN,
                    225: 
                    226: With raw partitions, one has a disklabel (or gpt) partition sized for
                    227: each virtual disk to be used by the domU.  (If you are able to predict
                    228: how domU usage will evolve, please add an explanation to the HOWTO.
                    229: Seriously, needs tend to change over time.)
                    230: 
1.27      jnemeth   231: One can use [lvm(8)](/guide/lvm/) to create logical devices to use
                    232: for domU disks.  This is almost as efficient as raw disk partitions
                    233: and more flexible.  Hence raw disk partitions should typically not
                    234: be used.
1.19      gdt       235: 
                    236: One can use files in the dom0 filesystem, typically created by dd'ing
                    237: /dev/zero to create a specific size.  This is somewhat less efficient,
                    238: but very convenient, as one can cp the files for backup, or move them
                    239: between dom0 hosts.
                    240: 
                    241: Finally, in theory one can place the files backing the domU disks in a
                    242: SAN.  (This is an invitation for someone who has done this to add a
                    243: HOWTO page.)
1.1       mspo      244: 
1.19      gdt       245: Installation of Xen
                    246: -------------------
1.1       mspo      247: 
1.20      gdt       248: In the dom0, install sysutils/xenkernel42 and sysutils/xentools42 from
                    249: pkgsrc (or another matching pair).
                    250: See [the pkgsrc
                    251: documentation](http://www.NetBSD.org/docs/pkgsrc/) for help with pkgsrc.
                    252: 
                    253: For Xen 3.1, support for HVM guests is in sysutils/xentool3-hvm.  More
                    254: recent versions have HVM support integrated in the main xentools
                    255: package.  It is entirely reasonable to run only PV guests.
                    256: 
                    257: Next you need to install the selected Xen kernel itself, which is
                    258: installed by pkgsrc as "/usr/pkg/xen*-kernel/xen.gz".  Copy it to /.
                    259: For debugging, one may copy xen-debug.gz; this is conceptually similar
                    260: to DIAGNOSTIC and DEBUG in NetBSD.  xen-debug.gz is basically only
                    261: useful with a serial console.  Then, place a NetBSD XEN3_DOM0 kernel
                    262: in /, copied from releasedir/amd64/binary/kernel/netbsd-XEN3_DOM0.gz
                    263: of a NetBSD build.  Both xen and NetBSD may be left compressed.  (If
                    264: using i386, use releasedir/i386/binary/kernel/netbsd-XEN3PAE_DOM0.gz.)
                    265: 
                    266: In a dom0 kernel, kernfs is mandatory for xend to comunicate with the
                    267: kernel, so ensure that /kern is in fstab.
                    268: 
                    269: Because you already installed NetBSD, you have a working boot setup
                    270: with an MBR bootblock, either bootxx_ffsv1 or bootxx_ffsv2 at the
                    271: beginning of your root filesystem, /boot present, and likely
                    272: /boot.cfg.  (If not, fix before continuing!)
                    273: 
                    274: See boot.cfg(5) for an example.  The basic line is
                    275: 
1.37      gdt       276:         menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=256M
1.20      gdt       277: 
                    278: which specifies that the dom0 should have 256M, leaving the rest to be
1.37      gdt       279: allocated for domUs.  In an attempt to add performance, one can also
                    280: add
                    281: 
                    282:         dom0_max_vcpus=1 dom0_vcpus_pin
                    283: 
                    284: to force only one vcpu to be provided (since NetBSD dom0 can't use
                    285: more) and to pin that vcpu to a physical cpu.  TODO: benchmark this.
1.20      gdt       286: 
                    287: As with non-Xen systems, you should have a line to boot /netbsd (a
                    288: kernel that works without Xen) and fallback versions of the non-Xen
                    289: kernel, Xen, and the dom0 kernel.
1.1       mspo      290: 
1.28      gdt       291: The [HowTo on Installing into
                    292: RAID-1](http://mail-index.NetBSD.org/port-xen/2006/03/01/0010.html)
                    293: explains how to set up booting a dom0 with Xen using grub with
                    294: NetBSD's RAIDframe.  (This is obsolete with the use of NetBSD's native
                    295: boot.)
                    296: 
1.21      gdt       297: Configuring Xen
                    298: ---------------
                    299: 
                    300: Now, you have a system that will boot Xen and the dom0 kernel, and
                    301: just run the dom0 kernel.  There will be no domUs, and none can be
1.31      gdt       302: started because you still have to configure the dom0 tools.  The
                    303: daemons which should be run vary with Xen version and with whether one
                    304: is using xm or xl.  Note that xend is for supporting "xm", and should
                    305: only be used if you plan on using "xm".  Do NOT enable xend if you
                    306: plan on using "xl" as it will cause problems.
1.21      gdt       307: 
1.43      gdt       308: The installation of NetBSD should already have created devices for xen
                    309: (xencons, xenevt), but if they are not present, create them:
                    310: 
                    311:         cd /dev && sh MAKEDEV xen
                    312: 
1.31      gdt       313: TODO: Give 3.1 advice (or remove it from pkgsrc).
                    314: 
                    315: For 3.3 (and thus xm), add to rc.conf (but note that you should have
                    316: installed 4.1 or 4.2):
                    317: 
1.32      gdt       318:         xend=YES
                    319:         xenbackendd=YES
1.31      gdt       320: 
1.33      gdt       321: For 4.1 (and thus xm; xl is believed not to work well), add to rc.conf:
1.31      gdt       322: 
                    323:         xend=YES
                    324:         xencommons=YES
                    325: 
                    326: TODO: Explain why if xm is preferred on 4.1, rc.d/xendomains has xl.
1.33      gdt       327: Or fix the package.
1.31      gdt       328: 
1.33      gdt       329: For 4.2 with xm, add to rc.conf
                    330: 
                    331:         xend=YES
                    332:         xencommons=YES
                    333: 
                    334: For 4.2 with xl (preferred), add to rc.conf:
1.31      gdt       335: 
                    336:         TODO: explain if there is a xend replacement
                    337:         xencommons=YES
                    338: 
                    339: TODO: Recommend for/against xen-watchdog.
1.27      jnemeth   340: 
1.43      gdt       341: After you have configured the daemons and either started them or
1.42      gdt       342: rebooted, run the following (or use xl) to inspect Xen's boot
                    343: messages, available resources, and running domains:
1.34      gdt       344: 
1.43      gdt       345:         # xm dmesg
                    346:        [xen's boot info]
                    347:         # xm info
                    348:        [available memory, etc.]
                    349:         # xm list
                    350:         Name              Id  Mem(MB)  CPU  State  Time(s)  Console
                    351:         Domain-0           0       64    0  r----     58.1
1.33      gdt       352: 
1.41      gdt       353: anita (for testing NetBSD)
                    354: --------------------------
                    355: 
                    356: With the setup so far, one should be able to run anita (see
                    357: pkgsrc/sysutils/py-anita) to test NetBSD releases, by doing (as root,
                    358: because anita must create a domU):
                    359: 
                    360:         anita --vmm=xm test file:///usr/obj/i386/
                    361: 
                    362: Alternatively, one can use --vmm=xl to use xl-based domU creation instead.
                    363: TODO: check this.
                    364: 
1.40      gdt       365: Xen-specific NetBSD issues
                    366: --------------------------
                    367: 
                    368: There are (at least) two additional things different about NetBSD as a
                    369: dom0 kernel compared to hardware.
                    370: 
                    371: One is that modules are not usable in DOM0 kernels, so one must
                    372: compile in what's needed.  It's not really that modules cannot work,
                    373: but that modules must be built for XEN3_DOM0 because some of the
                    374: defines change and the normal module builds don't do this.  Basically,
                    375: enabling Xen changes the kernel ABI, and the module build system
                    376: doesn't cope with this.
                    377: 
                    378: The other difference is that XEN3_DOM0 does not have exactly the same
                    379: options as GENERIC.  While it is debatable whether or not this is a
                    380: bug, users should be aware of this and can simply add missing config
                    381: items if desired.
                    382: 
1.15      gdt       383: Updating NetBSD in a dom0
                    384: -------------------------
                    385: 
                    386: This is just like updating NetBSD on bare hardware, assuming the new
                    387: version supports the version of Xen you are running.  Generally, one
                    388: replaces the kernel and reboots, and then overlays userland binaries
                    389: and adjusts /etc.
                    390: 
                    391: Note that one must update both the non-Xen kernel typically used for
                    392: rescue purposes and the DOM0 kernel used with Xen.
                    393: 
1.22      gdt       394: To convert from grub to /boot, install an mbr bootblock with fdisk,
                    395: bootxx_ with installboot, /boot and /boot.cfg.  This really should be
                    396: no different than completely reinstalling boot blocks on a non-Xen
                    397: system.
                    398: 
1.15      gdt       399: Updating Xen versions
                    400: ---------------------
                    401: 
1.21      gdt       402: Updating Xen is conceptually not difficult, but can run into all the
                    403: issues found when installing Xen.  Assuming migration from 4.1 to 4.2,
                    404: remove the xenkernel41 and xentools41 packages and install the
                    405: xenkernel42 and xentools42 packages.  Copy the 4.2 xen.gz to /.
                    406: 
                    407: Ensure that the contents of /etc/rc.d/xen* are correct.  Enable the
                    408: correct set of daemons.  Ensure that the domU config files are valid
                    409: for the new version.
1.15      gdt       410: 
1.28      gdt       411: 
                    412: Unprivileged domains (domU)
                    413: ===========================
                    414: 
                    415: This section describes general concepts about domUs.  It does not
1.33      gdt       416: address specific domU operating systems or how to install them.  The
                    417: config files for domUs are typically in /usr/pkg/etc/xen, and are
                    418: typically named so that the file anme, domU name and the domU's host
                    419: name match.
                    420: 
                    421: The domU is provided with cpu and memory by Xen, configured by the
                    422: dom0.  The domU is provided with disk and network by the dom0,
                    423: mediated by Xen, and configured in the dom0.
                    424: 
                    425: Entropy in domUs can be an issue; physical disks and network are on
                    426: the dom0.  NetBSD's /dev/random system works, but is often challenged.
                    427: 
1.48    ! gdt       428: Config files
        !           429: ------------
        !           430: 
        !           431: There is no good order to present config files and the concepts
        !           432: surrounding what is being configured.  We first show an example config
        !           433: file, and then in the various sections give details.
        !           434: 
        !           435: See (at least in xentools41) /usr/pkg/share/examples/xen/xmexample*,
        !           436: for a large number of well-commented examples, mostly for running
        !           437: GNU/Linux.
        !           438: 
        !           439: The following is an example minimal domain configuration file
        !           440: "/usr/pkg/etc/xen/foo".  It is (with only a name change) an actual
        !           441: known working config file on Xen 4.1 (NetBSD 5 amd64 dom0 and NetBSD 5
        !           442: i386 domU).  The domU serves as a network file server.
        !           443: 
        !           444:         # -*- mode: python; -*-
        !           445: 
        !           446:         kernel = "/netbsd-XEN3PAE_DOMU-i386-foo.gz"
        !           447:         memory = 1024
        !           448:         vif = [ 'mac=aa:00:00:d1:00:09,bridge=bridge0' ]
        !           449:         disk = [ 'file:/n0/xen/foo-wd0,0x0,w',
        !           450:                  'file:/n0/xen/foo-wd1,0x1,w' ]
        !           451: 
        !           452: The domain will have the same name as the file.  The kernel has the
        !           453: host/domU name in it, so that on the dom0 one can update the various
        !           454: domUs independently.  The vif line causes an interface to be provided,
        !           455: with a specific mac address (do not reuse MAC addresses!), in bridge
        !           456: mode.  Two disks are provided, and they are both writable; the bits
        !           457: are stored in files and Xen attaches them to a vnd(4) device in the
        !           458: dom0 on domain creation.  The system treates xbd0 as the boot device
        !           459: without needing explicit configuration.
        !           460: 
        !           461: By default xm looks for domain config files in /usr/pkg/etc/xen.  Note
        !           462: that "xm create" takes the name of a config file, while other commands
        !           463: take the name of a domain.  To create the domain, connect to the
        !           464: console, create the domain while attaching the console, shutdown the
        !           465: domain, and see if it has finished stopping, do (or xl with Xen >=
        !           466: 4.2):
        !           467: 
        !           468:         xm create foo
        !           469:         xm console foo
        !           470:         xm create -c foo
        !           471:         xm shutdown foo
        !           472:        xm list
        !           473: 
        !           474: Typing ^] will exit the console session.  Shutting down a domain is
        !           475: equivalent to pushing the power button; a NetBSD domU will receive a
        !           476: power-press event and do a clean shutdown.  Shutting down the dom0
        !           477: will trigger controlled shutdowns of all configured domUs.
        !           478: 
        !           479: domU kernels
        !           480: ------------
        !           481: 
        !           482: On a physical computer, the BIOS reads sector 0, and a chain of boot
        !           483: loaders finds and loads a kernel.  Normally this comes from the root
        !           484: filesystem.  With Xen domUs, the process is totally different.  The
        !           485: normal path is for the domU kernel to be a file in the dom0's
        !           486: filesystem.  At the request of the dom0, Xen loads that kernel into a
        !           487: new domU instance and starts execution.  While domU kernels can be
        !           488: anyplace, reasonable places to store domU kernels on the dom0 are in /
        !           489: (so they are near the dom0 kernel), in /usr/pkg/etc/xen (near the
        !           490: config files), or in /u0/xen (where the vdisks are).
        !           491: 
        !           492: See the VPS section near the end for discussion of alternate ways to
        !           493: obtain domU kernels.
        !           494: 
1.33      gdt       495: CPU and memory
                    496: --------------
                    497: 
1.48    ! gdt       498: A domain is provided with some number of vcpus, less than the number
        !           499: of cpus seen by the hypervisor.  (For a dom0, this is controlled by
        !           500: the boot argument "dom0_max_vcpus=1".)  For a domU, it is controlled
        !           501: from the config file by the "vcpus = N" directive.
        !           502: 
        !           503: A domain is provided with memory; this is controlled in the config
        !           504: file by "memory = N" (in megabytes).  In the straightforward case, the
        !           505: sum of the the memory allocated to the dom0 and all domUs must be less
1.33      gdt       506: than the available memory.
                    507: 
                    508: Xen also provides a "balloon" driver, which can be used to let domains
                    509: use more memory temporarily.  TODO: Explain better, and explain how
                    510: well it works with NetBSD.
1.28      gdt       511: 
                    512: Virtual disks
                    513: -------------
                    514: 
1.33      gdt       515: With the file/vnd style, typically one creates a directory,
                    516: e.g. /u0/xen, on a disk large enough to hold virtual disks for all
                    517: domUs.  Then, for each domU disk, one writes zeros to a file that then
                    518: serves to hold the virtual disk's bits; a suggested name is foo-xbd0
                    519: for the first virtual disk for the domU called foo.  Writing zeros to
                    520: the file serves two purposes.  One is that preallocating the contents
                    521: improves performance.  The other is that vnd on sparse files has
                    522: failed to work.  TODO: give working/notworking NetBSD versions for
                    523: sparse vnd.  Note that the use of file/vnd for Xen is not really
                    524: different than creating a file-backed virtual disk for some other
1.39      gdt       525: purpose, except that xentools handles the vnconfig commands.  To
                    526: create an empty 4G virtual disk, simply do
                    527: 
                    528:         dd if=/dev/zero of=foo-xbd0 bs=1m count=4096
1.33      gdt       529: 
                    530: With the lvm style, one creates logical devices.  They are then used
1.48    ! gdt       531: similarly to vnds.  TODO: Add an example with lvm.
        !           532: 
        !           533: In domU config files, the disks are defined as a sequence of 3-tuples.
        !           534: The first element is "method:/path/to/disk".  Common methods are
        !           535: "file:" for file-backed vnd. and "phy:" for something that is already
        !           536: a (TODO: character or block) device.
        !           537: 
        !           538: The second element is an artifact of how virtual disks are passed to
        !           539: Linux, and a source of confusion with NetBSD Xen usage.  Linux domUs
        !           540: are given a device name to associate with the disk, and values like
        !           541: "hda1" or "sda1" are common.  In a NetBSD domU, the first disk appears
        !           542: as xbd0, the second as xbd1, and so on.  However, xm/xl demand a
        !           543: second argument.  The name given is converted to a major/minor by
        !           544: consulting /dev and this is passed to the domU (TODO: check this).  In
        !           545: the general case, the dom0 and domU can be different operating
        !           546: systems, and it is an unwarranted assumption that they have consistent
        !           547: numbering in /dev, or even that the dom0 OS has a /dev.  With NetBSD
        !           548: as both dom0 and domU, using values of 0x0 for the first disk and 0x1
        !           549: for the second works fine and avoids this issue.
        !           550: 
        !           551: The third element is "w" for writable disks, and "r" for read-only
        !           552: disks.
1.28      gdt       553: 
                    554: Virtual Networking
                    555: ------------------
                    556: 
1.46      gdt       557: Xen provides virtual ethernets, each of which connects the dom0 and a
                    558: domU.  For each virtual network, there is an interface "xvifN.M" in
                    559: the dom0, and in domU index N, a matching interface xennetM (NetBSD
                    560: name).  The interfaces behave as if there is an Ethernet with two
                    561: adaptors connected.  From this primitive, one can construct various
                    562: configurations.  We focus on two common and useful cases for which
                    563: there are existing scripts: bridging and NAT.
1.28      gdt       564: 
1.48    ! gdt       565: With bridging (in the example above), the domU perceives itself to be
        !           566: on the same network as the dom0.  For server virtualization, this is
        !           567: usually best.  Bridging is accomplished by creating a bridge(4) device
        !           568: and adding the dom0's physical interface and the various xvifN.0
        !           569: interfaces to the bridge.  One specifies "bridge=bridge0" in the domU
        !           570: config file.  The bridge must be set up already in the dom0; an
        !           571: example /etc/ifconfig.bridge0 is:
1.46      gdt       572: 
                    573:         create
                    574:         up
                    575:         !brconfig bridge0 add wm0
1.28      gdt       576: 
                    577: With NAT, the domU perceives itself to be behind a NAT running on the
                    578: dom0.  This is often appropriate when running Xen on a workstation.
1.48    ! gdt       579: TODO: NAT appears to be configured by "vif = [ '' ]".
1.28      gdt       580: 
1.33      gdt       581: Sizing domains
                    582: --------------
                    583: 
                    584: Modern x86 hardware has vast amounts of resources.  However, many
                    585: virtual servers can function just fine on far less.  A system with
                    586: 256M of RAM and a 4G disk can be a reasonable choice.  Note that it is
                    587: far easier to adjust virtual resources than physical ones.  For
                    588: memory, it's just a config file edit and a reboot.  For disk, one can
                    589: create a new file and vnconfig it (or lvm), and then dump/restore,
                    590: just like updating physical disks, but without having to be there and
                    591: without those pesky connectors.
                    592: 
1.48    ! gdt       593: Starting domains automatically
        !           594: ------------------------------
1.28      gdt       595: 
1.48    ! gdt       596: To start domains foo at bar at boot and shut them down cleanly on dom0
        !           597: shutdown, in rc.conf add:
1.28      gdt       598: 
1.48    ! gdt       599:         xendomains="foo bar"
1.28      gdt       600: 
                    601: TODO: Explain why 4.1 rc.d/xendomains has xl, when one should use xm
1.48    ! gdt       602: on 4.1.  Or fix the xentools41 package to have xm
1.28      gdt       603: 
                    604: Creating specific unprivileged domains (domU)
                    605: =============================================
1.14      gdt       606: 
                    607: Creating domUs is almost entirely independent of operating system.  We
                    608: first explain NetBSD, and then differences for Linux and Solaris.
1.43      gdt       609: Note that you must have already completed the dom0 setup so that "xm
                    610: list" (or "xl list") works.
1.14      gdt       611: 
                    612: Creating an unprivileged NetBSD domain (domU)
                    613: ---------------------------------------------
1.1       mspo      614: 
                    615: 'xm create' allows you to create a new domain. It uses a config file in
                    616: PKG\_SYSCONFDIR for its parameters. By default, this file will be in
1.5       mspo      617: `/usr/pkg/etc/xen/`. On creation, a kernel has to be specified, which
                    618: will be executed in the new domain (this kernel is in the *domain0* file
                    619: system, not on the new domain virtual disk; but please note, you should
                    620: install the same kernel into *domainU* as `/netbsd` in order to make
1.27      jnemeth   621: your system tools, like savecore(8), work). A suitable kernel is
1.5       mspo      622: provided as part of the i386 and amd64 binary sets: XEN3\_DOMU.
1.1       mspo      623: 
                    624: Here is an /usr/pkg/etc/xen/nbsd example config file:
                    625: 
1.3       mspo      626:     #  -*- mode: python; -*-
                    627:     #============================================================================
                    628:     # Python defaults setup for 'xm create'.
                    629:     # Edit this file to reflect the configuration of your system.
                    630:     #============================================================================
1.5       mspo      631: 
1.3       mspo      632:     #----------------------------------------------------------------------------
                    633:     # Kernel image file. This kernel will be loaded in the new domain.
                    634:     kernel = "/home/bouyer/netbsd-XEN3_DOMU"
                    635:     #kernel = "/home/bouyer/netbsd-INSTALL_XEN3_DOMU"
1.5       mspo      636: 
1.3       mspo      637:     # Memory allocation (in megabytes) for the new domain.
                    638:     memory = 128
1.5       mspo      639: 
1.3       mspo      640:     # A handy name for your new domain. This will appear in 'xm list',
                    641:     # and you can use this as parameters for xm in place of the domain
                    642:     # number. All domains must have different names.
                    643:     #
                    644:     name = "nbsd"
1.5       mspo      645: 
1.3       mspo      646:     # The number of virtual CPUs this domain has.
                    647:     #
                    648:     vcpus = 1
1.5       mspo      649: 
1.3       mspo      650:     #----------------------------------------------------------------------------
                    651:     # Define network interfaces for the new domain.
1.5       mspo      652: 
1.3       mspo      653:     # Number of network interfaces (must be at least 1). Default is 1.
                    654:     nics = 1
1.5       mspo      655: 
1.3       mspo      656:     # Define MAC and/or bridge for the network interfaces.
                    657:     #
                    658:     # The MAC address specified in ``mac'' is the one used for the interface
                    659:     # in the new domain. The interface in domain0 will use this address XOR'd
                    660:     # with 00:00:00:01:00:00 (i.e. aa:00:00:51:02:f0 in our example). Random
                    661:     # MACs are assigned if not given.
                    662:     #
                    663:     # ``bridge'' is a required parameter, which will be passed to the
                    664:     # vif-script called by xend(8) when a new domain is created to configure
                    665:     # the new xvif interface in domain0.
                    666:     #
                    667:     # In this example, the xvif is added to bridge0, which should have been
                    668:     # set up prior to the new domain being created -- either in the
                    669:     # ``network'' script or using a /etc/ifconfig.bridge0 file.
                    670:     #
                    671:     vif = [ 'mac=aa:00:00:50:02:f0, bridge=bridge0' ]
1.5       mspo      672: 
1.3       mspo      673:     #----------------------------------------------------------------------------
                    674:     # Define the disk devices you want the domain to have access to, and
                    675:     # what you want them accessible as.
                    676:     #
                    677:     # Each disk entry is of the form:
                    678:     #
1.5       mspo      679:     #   phy:DEV,VDEV,MODE
1.3       mspo      680:     #
                    681:     # where DEV is the device, VDEV is the device name the domain will see,
                    682:     # and MODE is r for read-only, w for read-write.  You can also create
                    683:     # file-backed domains using disk entries of the form:
                    684:     #
1.5       mspo      685:     #   file:PATH,VDEV,MODE
1.3       mspo      686:     #
                    687:     # where PATH is the path to the file used as the virtual disk, and VDEV
                    688:     # and MODE have the same meaning as for ``phy'' devices.
                    689:     #
                    690:     # VDEV doesn't really matter for a NetBSD guest OS (it's just used as an index),
                    691:     # but it does for Linux.
                    692:     # Worse, the device has to exist in /dev/ of domain0, because xm will
                    693:     # try to stat() it. This means that in order to load a Linux guest OS
                    694:     # from a NetBSD domain0, you'll have to create /dev/hda1, /dev/hda2, ...
                    695:     # on domain0, with the major/minor from Linux :(
                    696:     # Alternatively it's possible to specify the device number in hex,
                    697:     # e.g. 0x301 for /dev/hda1, 0x302 for /dev/hda2, etc ...
1.5       mspo      698: 
1.3       mspo      699:     disk = [ 'phy:/dev/wd0e,0x1,w' ]
                    700:     #disk = [ 'file:/var/xen/nbsd-disk,0x01,w' ]
                    701:     #disk = [ 'file:/var/xen/nbsd-disk,0x301,w' ]
1.5       mspo      702: 
1.3       mspo      703:     #----------------------------------------------------------------------------
                    704:     # Set the kernel command line for the new domain.
1.5       mspo      705: 
1.3       mspo      706:     # Set root device. This one does matter for NetBSD
                    707:     root = "xbd0"
                    708:     # extra parameters passed to the kernel
                    709:     # this is where you can set boot flags like -s, -a, etc ...
                    710:     #extra = ""
1.5       mspo      711: 
1.3       mspo      712:     #----------------------------------------------------------------------------
                    713:     # Set according to whether you want the domain restarted when it exits.
                    714:     # The default is False.
                    715:     #autorestart = True
1.5       mspo      716: 
1.3       mspo      717:     # end of nbsd config file ====================================================
1.1       mspo      718: 
                    719: When a new domain is created, xen calls the
1.5       mspo      720: `/usr/pkg/etc/xen/vif-bridge` script for each virtual network interface
                    721: created in *domain0*. This can be used to automatically configure the
                    722: xvif?.? interfaces in *domain0*. In our example, these will be bridged
                    723: with the bridge0 device in *domain0*, but the bridge has to exist first.
                    724: To do this, create the file `/etc/ifconfig.bridge0` and make it look
                    725: like this:
1.1       mspo      726: 
1.3       mspo      727:     create
                    728:     !brconfig $int add ex0 up
1.1       mspo      729: 
1.5       mspo      730: (replace `ex0` with the name of your physical interface). Then bridge0
1.27      jnemeth   731: will be created on boot. See the bridge(4) man page for details.
1.1       mspo      732: 
1.5       mspo      733: So, here is a suitable `/usr/pkg/etc/xen/vif-bridge` for xvif?.? (a
                    734: working vif-bridge is also provided with xentools20) configuring:
1.1       mspo      735: 
1.5       mspo      736:     #!/bin/sh
1.3       mspo      737:     #============================================================================
1.48    ! gdt       738:     # $NetBSD: howto.mdwn,v 1.47 2014/12/26 18:35:45 gdt Exp $
1.3       mspo      739:     #
                    740:     # /usr/pkg/etc/xen/vif-bridge
                    741:     #
                    742:     # Script for configuring a vif in bridged mode with a dom0 interface.
                    743:     # The xend(8) daemon calls a vif script when bringing a vif up or down.
                    744:     # The script name to use is defined in /usr/pkg/etc/xen/xend-config.sxp
                    745:     # in the ``vif-script'' field.
                    746:     #
                    747:     # Usage: vif-bridge up|down [var=value ...]
                    748:     #
                    749:     # Actions:
1.5       mspo      750:     #    up     Adds the vif interface to the bridge.
                    751:     #    down   Removes the vif interface from the bridge.
1.3       mspo      752:     #
                    753:     # Variables:
1.5       mspo      754:     #    domain name of the domain the interface is on (required).
                    755:     #    vifq   vif interface name (required).
                    756:     #    mac    vif MAC address (required).
                    757:     #    bridge bridge to add the vif to (required).
1.3       mspo      758:     #
                    759:     # Example invocation:
                    760:     #
                    761:     # vif-bridge up domain=VM1 vif=xvif1.0 mac="ee:14:01:d0:ec:af" bridge=bridge0
                    762:     #
                    763:     #============================================================================
1.5       mspo      764: 
1.3       mspo      765:     # Exit if anything goes wrong
                    766:     set -e
1.5       mspo      767: 
1.3       mspo      768:     echo "vif-bridge $*"
1.5       mspo      769: 
1.3       mspo      770:     # Operation name.
                    771:     OP=$1; shift
1.5       mspo      772: 
1.3       mspo      773:     # Pull variables in args into environment
                    774:     for arg ; do export "${arg}" ; done
1.5       mspo      775: 
1.3       mspo      776:     # Required parameters. Fail if not set.
                    777:     domain=${domain:?}
                    778:     vif=${vif:?}
                    779:     mac=${mac:?}
                    780:     bridge=${bridge:?}
1.5       mspo      781: 
1.3       mspo      782:     # Optional parameters. Set defaults.
                    783:     ip=${ip:-''}   # default to null (do nothing)
1.5       mspo      784: 
1.3       mspo      785:     # Are we going up or down?
                    786:     case $OP in
1.5       mspo      787:     up) brcmd='add' ;;
1.3       mspo      788:     down)   brcmd='delete' ;;
                    789:     *)
1.5       mspo      790:         echo 'Invalid command: ' $OP
                    791:         echo 'Valid commands are: up, down'
                    792:         exit 1
                    793:         ;;
1.3       mspo      794:     esac
1.5       mspo      795: 
1.3       mspo      796:     # Don't do anything if the bridge is "null".
                    797:     if [ "${bridge}" = "null" ] ; then
1.5       mspo      798:         exit
1.3       mspo      799:     fi
1.5       mspo      800: 
1.3       mspo      801:     # Don't do anything if the bridge doesn't exist.
                    802:     if ! ifconfig -l | grep "${bridge}" >/dev/null; then
1.5       mspo      803:         exit
1.3       mspo      804:     fi
1.5       mspo      805: 
1.3       mspo      806:     # Add/remove vif to/from bridge.
                    807:     ifconfig x${vif} $OP
                    808:     brconfig ${bridge} ${brcmd} x${vif}
1.1       mspo      809: 
                    810: Now, running
                    811: 
1.3       mspo      812:     xm create -c /usr/pkg/etc/xen/nbsd
1.1       mspo      813: 
1.5       mspo      814: should create a domain and load a NetBSD kernel in it. (Note: `-c`
                    815: causes xm to connect to the domain's console once created.) The kernel
                    816: will try to find its root file system on xbd0 (i.e., wd0e) which hasn't
                    817: been created yet. wd0e will be seen as a disk device in the new domain,
                    818: so it will be 'sub-partitioned'. We could attach a ccd to wd0e in
                    819: *domain0* and partition it, newfs and extract the NetBSD/i386 or amd64
                    820: tarballs there, but there's an easier way: load the
                    821: `netbsd-INSTALL_XEN3_DOMU` kernel provided in the NetBSD binary sets.
                    822: Like other install kernels, it contains a ramdisk with sysinst, so you
                    823: can install NetBSD using sysinst on your new domain.
1.1       mspo      824: 
                    825: If you want to install NetBSD/Xen with a CDROM image, the following line
1.5       mspo      826: should be used in the `/usr/pkg/etc/xen/nbsd` file:
1.1       mspo      827: 
1.3       mspo      828:     disk = [ 'phy:/dev/wd0e,0x1,w', 'phy:/dev/cd0a,0x2,r' ]
1.1       mspo      829: 
                    830: After booting the domain, the option to install via CDROM may be
1.5       mspo      831: selected. The CDROM device should be changed to `xbd1d`.
1.1       mspo      832: 
1.5       mspo      833: Once done installing, `halt -p` the new domain (don't reboot or halt, it
                    834: would reload the INSTALL\_XEN3\_DOMU kernel even if you changed the
1.1       mspo      835: config file), switch the config file back to the XEN3\_DOMU kernel, and
1.5       mspo      836: start the new domain again. Now it should be able to use `root on xbd0a`
                    837: and you should have a second, functional NetBSD system on your xen
                    838: installation.
1.1       mspo      839: 
                    840: When the new domain is booting you'll see some warnings about *wscons*
                    841: and the pseudo-terminals. These can be fixed by editing the files
1.5       mspo      842: `/etc/ttys` and `/etc/wscons.conf`. You must disable all terminals in
                    843: `/etc/ttys`, except *console*, like this:
1.1       mspo      844: 
1.3       mspo      845:     console "/usr/libexec/getty Pc"         vt100   on secure
                    846:     ttyE0   "/usr/libexec/getty Pc"         vt220   off secure
                    847:     ttyE1   "/usr/libexec/getty Pc"         vt220   off secure
                    848:     ttyE2   "/usr/libexec/getty Pc"         vt220   off secure
                    849:     ttyE3   "/usr/libexec/getty Pc"         vt220   off secure
1.1       mspo      850: 
1.5       mspo      851: Finally, all screens must be commented out from `/etc/wscons.conf`.
1.1       mspo      852: 
                    853: It is also desirable to add
                    854: 
1.3       mspo      855:     powerd=YES
1.1       mspo      856: 
1.5       mspo      857: in rc.conf. This way, the domain will be properly shut down if
                    858: `xm shutdown -R` or `xm shutdown -H` is used on the domain0.
1.1       mspo      859: 
                    860: Your domain should be now ready to work, enjoy.
                    861: 
1.14      gdt       862: Creating an unprivileged Linux domain (domU)
1.5       mspo      863: --------------------------------------------
1.1       mspo      864: 
                    865: Creating unprivileged Linux domains isn't much different from
                    866: unprivileged NetBSD domains, but there are some details to know.
                    867: 
                    868: First, the second parameter passed to the disk declaration (the '0x1' in
                    869: the example below)
                    870: 
1.3       mspo      871:     disk = [ 'phy:/dev/wd0e,0x1,w' ]
1.1       mspo      872: 
                    873: does matter to Linux. It wants a Linux device number here (e.g. 0x300
                    874: for hda). Linux builds device numbers as: (major \<\< 8 + minor). So,
                    875: hda1 which has major 3 and minor 1 on a Linux system will have device
                    876: number 0x301. Alternatively, devices names can be used (hda, hdb, ...)
                    877: as xentools has a table to map these names to devices numbers. To export
                    878: a partition to a Linux guest we can use:
                    879: 
1.3       mspo      880:     disk = [ 'phy:/dev/wd0e,0x300,w' ]
                    881:     root = "/dev/hda1 ro"
1.1       mspo      882: 
                    883: and it will appear as /dev/hda on the Linux system, and be used as root
                    884: partition.
                    885: 
                    886: To install the Linux system on the partition to be exported to the guest
                    887: domain, the following method can be used: install sysutils/e2fsprogs
                    888: from pkgsrc. Use mke2fs to format the partition that will be the root
                    889: partition of your Linux domain, and mount it. Then copy the files from a
1.5       mspo      890: working Linux system, make adjustments in `/etc` (fstab, network
                    891: config). It should also be possible to extract binary packages such as
                    892: .rpm or .deb directly to the mounted partition using the appropriate
                    893: tool, possibly running under NetBSD's Linux emulation. Once the
                    894: filesystem has been populated, umount it. If desirable, the filesystem
                    895: can be converted to ext3 using tune2fs -j. It should now be possible to
                    896: boot the Linux guest domain, using one of the vmlinuz-\*-xenU kernels
                    897: available in the Xen binary distribution.
1.1       mspo      898: 
                    899: To get the linux console right, you need to add:
                    900: 
1.3       mspo      901:     extra = "xencons=tty1"
1.1       mspo      902: 
                    903: to your configuration since not all linux distributions auto-attach a
                    904: tty to the xen console.
                    905: 
1.14      gdt       906: Creating an unprivileged Solaris domain (domU)
1.5       mspo      907: ----------------------------------------------
1.1       mspo      908: 
                    909: Download an Opensolaris [release](http://opensolaris.org/os/downloads/)
                    910: or [development snapshot](http://genunix.org/) DVD image. Attach the DVD
1.5       mspo      911: image to a MAN.VND.4 device. Copy the kernel and ramdisk filesystem
                    912: image to your dom0 filesystem.
1.1       mspo      913: 
1.3       mspo      914:     dom0# mkdir /root/solaris
                    915:     dom0# vnconfig vnd0 osol-1002-124-x86.iso
                    916:     dom0# mount /dev/vnd0a /mnt
1.5       mspo      917: 
1.3       mspo      918:     ## for a 64-bit guest
                    919:     dom0# cp /mnt/boot/amd64/x86.microroot /root/solaris
                    920:     dom0# cp /mnt/platform/i86xpv/kernel/amd64/unix /root/solaris
1.5       mspo      921: 
1.3       mspo      922:     ## for a 32-bit guest
                    923:     dom0# cp /mnt/boot/x86.microroot /root/solaris
                    924:     dom0# cp /mnt/platform/i86xpv/kernel/unix /root/solaris
1.5       mspo      925: 
1.3       mspo      926:     dom0# umount /mnt
1.5       mspo      927:           
                    928: 
                    929: Keep the MAN.VND.4 configured. For some reason the boot process stalls
                    930: unless the DVD image is attached to the guest as a "phy" device. Create
                    931: an initial configuration file with the following contents. Substitute
                    932: */dev/wd0k* with an empty partition at least 8 GB large.
1.1       mspo      933: 
1.4       mspo      934:     memory = 640
                    935:     name = 'solaris'
                    936:     disk = [ 'phy:/dev/wd0k,0,w' ]
                    937:     disk += [ 'phy:/dev/vnd0d,6:cdrom,r' ]
                    938:     vif = [ 'bridge=bridge0' ]
                    939:     kernel = '/root/solaris/unix'
                    940:     ramdisk = '/root/solaris/x86.microroot'
                    941:     # for a 64-bit guest
                    942:     extra = '/platform/i86xpv/kernel/amd64/unix - nowin -B install_media=cdrom'
                    943:     # for a 32-bit guest
                    944:     #extra = '/platform/i86xpv/kernel/unix - nowin -B install_media=cdrom'
1.5       mspo      945:           
                    946: 
1.1       mspo      947: Start the guest.
                    948: 
1.4       mspo      949:     dom0# xm create -c solaris.cfg
                    950:     Started domain solaris
                    951:                           v3.3.2 chgset 'unavailable'
                    952:     SunOS Release 5.11 Version snv_124 64-bit
                    953:     Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.
                    954:     Use is subject to license terms.
                    955:     Hostname: opensolaris
                    956:     Remounting root read/write
                    957:     Probing for device nodes ...
                    958:     WARNING: emlxs: ddi_modopen drv/fct failed: err 2
                    959:     Preparing live image for use
                    960:     Done mounting Live image
1.5       mspo      961:           
1.1       mspo      962: 
                    963: Make sure the network is configured. Note that it can take a minute for
                    964: the xnf0 interface to appear.
                    965: 
1.4       mspo      966:     opensolaris console login: jack
                    967:     Password: jack
                    968:     Sun Microsystems Inc.   SunOS 5.11      snv_124 November 2008
                    969:     jack@opensolaris:~$ pfexec sh
                    970:     sh-3.2# ifconfig -a
                    971:     sh-3.2# exit
1.5       mspo      972:           
1.1       mspo      973: 
                    974: Set a password for VNC and start the VNC server which provides the X11
                    975: display where the installation program runs.
                    976: 
1.4       mspo      977:     jack@opensolaris:~$ vncpasswd
                    978:     Password: solaris
                    979:     Verify: solaris
                    980:     jack@opensolaris:~$ cp .Xclients .vnc/xstartup
                    981:     jack@opensolaris:~$ vncserver :1
1.5       mspo      982:           
1.1       mspo      983: 
1.5       mspo      984: From a remote machine connect to the VNC server. Use `ifconfig xnf0` on
                    985: the guest to find the correct IP address to use.
1.1       mspo      986: 
1.4       mspo      987:     remote$ vncviewer 172.18.2.99:1
1.5       mspo      988:           
1.1       mspo      989: 
                    990: It is also possible to launch the installation on a remote X11 display.
                    991: 
1.4       mspo      992:     jack@opensolaris:~$ export DISPLAY=172.18.1.1:0
                    993:     jack@opensolaris:~$ pfexec gui-install
1.5       mspo      994:            
1.1       mspo      995: 
                    996: After the GUI installation is complete you will be asked to reboot.
                    997: Before that you need to determine the ZFS ID for the new boot filesystem
                    998: and update the configuration file accordingly. Return to the guest
                    999: console.
                   1000: 
1.4       mspo     1001:     jack@opensolaris:~$ pfexec zdb -vvv rpool | grep bootfs
                   1002:                     bootfs = 43
                   1003:     ^C
                   1004:     jack@opensolaris:~$
1.5       mspo     1005:            
1.1       mspo     1006: 
                   1007: The final configuration file should look like this. Note in particular
                   1008: the last line.
                   1009: 
1.4       mspo     1010:     memory = 640
                   1011:     name = 'solaris'
                   1012:     disk = [ 'phy:/dev/wd0k,0,w' ]
                   1013:     vif = [ 'bridge=bridge0' ]
                   1014:     kernel = '/root/solaris/unix'
                   1015:     ramdisk = '/root/solaris/x86.microroot'
                   1016:     extra = '/platform/i86xpv/kernel/amd64/unix -B zfs-bootfs=rpool/43,bootpath="/xpvd/xdf@0:a"'
1.5       mspo     1017:            
1.1       mspo     1018: 
                   1019: Restart the guest to verify it works correctly.
                   1020: 
1.4       mspo     1021:     dom0# xm destroy solaris
                   1022:     dom0# xm create -c solaris.cfg
                   1023:     Using config file "./solaris.cfg".
                   1024:     v3.3.2 chgset 'unavailable'
                   1025:     Started domain solaris
                   1026:     SunOS Release 5.11 Version snv_124 64-bit
                   1027:     Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.
                   1028:     Use is subject to license terms.
                   1029:     WARNING: emlxs: ddi_modopen drv/fct failed: err 2
                   1030:     Hostname: osol
                   1031:     Configuring devices.
                   1032:     Loading smf(5) service descriptions: 160/160
                   1033:     svccfg import warnings. See /var/svc/log/system-manifest-import:default.log .
                   1034:     Reading ZFS config: done.
                   1035:     Mounting ZFS filesystems: (6/6)
                   1036:     Creating new rsa public/private host key pair
                   1037:     Creating new dsa public/private host key pair
1.5       mspo     1038: 
1.4       mspo     1039:     osol console login:
1.5       mspo     1040:            
1.1       mspo     1041: 
                   1042: Using PCI devices in guest domains
1.14      gdt      1043: ----------------------------------
1.1       mspo     1044: 
                   1045: The domain0 can give other domains access to selected PCI devices. This
                   1046: can allow, for example, a non-privileged domain to have access to a
                   1047: physical network interface or disk controller. However, keep in mind
                   1048: that giving a domain access to a PCI device most likely will give the
                   1049: domain read/write access to the whole physical memory, as PCs don't have
                   1050: an IOMMU to restrict memory access to DMA-capable device. Also, it's not
                   1051: possible to export ISA devices to non-domain0 domains (which means that
                   1052: the primary VGA adapter can't be exported. A guest domain trying to
                   1053: access the VGA registers will panic).
                   1054: 
                   1055: This functionality is only available in NetBSD-5.1 (and later) domain0
                   1056: and domU. If the domain0 is NetBSD, it has to be running Xen 3.1, as
                   1057: support has not been ported to later versions at this time.
                   1058: 
                   1059: For a PCI device to be exported to a domU, is has to be attached to the
1.5       mspo     1060: `pciback` driver in domain0. Devices passed to the domain0 via the
                   1061: pciback.hide boot parameter will attach to `pciback` instead of the
                   1062: usual driver. The list of devices is specified as `(bus:dev.func)`,
                   1063: where bus and dev are 2-digit hexadecimal numbers, and func a
                   1064: single-digit number:
1.1       mspo     1065: 
1.4       mspo     1066:     pciback.hide=(00:0a.0)(00:06.0)
1.1       mspo     1067: 
                   1068: pciback devices should show up in the domain0's boot messages, and the
1.5       mspo     1069: devices should be listed in the `/kern/xen/pci` directory.
1.1       mspo     1070: 
1.5       mspo     1071: PCI devices to be exported to a domU are listed in the `pci` array of
                   1072: the domU's config file, with the format `'0000:bus:dev.func'`
1.1       mspo     1073: 
1.4       mspo     1074:     pci = [ '0000:00:06.0', '0000:00:0a.0' ]
1.1       mspo     1075: 
1.5       mspo     1076: In the domU an `xpci` device will show up, to which one or more pci
                   1077: busses will attach. Then the PCI drivers will attach to PCI busses as
                   1078: usual. Note that the default NetBSD DOMU kernels do not have `xpci` or
                   1079: any PCI drivers built in by default; you have to build your own kernel
                   1080: to use PCI devices in a domU. Here's a kernel config example:
1.1       mspo     1081: 
1.4       mspo     1082:     include         "arch/i386/conf/XEN3_DOMU"
                   1083:     #include         "arch/i386/conf/XENU"           # in NetBSD 3.0
1.5       mspo     1084: 
1.4       mspo     1085:     # Add support for PCI busses to the XEN3_DOMU kernel
                   1086:     xpci* at xenbus ?
                   1087:     pci* at xpci ?
1.5       mspo     1088: 
1.4       mspo     1089:     # Now add PCI and related devices to be used by this domain
                   1090:     # USB Controller and Devices
1.5       mspo     1091: 
1.4       mspo     1092:     # PCI USB controllers
                   1093:     uhci*   at pci? dev ? function ?        # Universal Host Controller (Intel)
1.5       mspo     1094: 
1.4       mspo     1095:     # USB bus support
                   1096:     usb*    at uhci?
1.5       mspo     1097: 
1.4       mspo     1098:     # USB Hubs
                   1099:     uhub*   at usb?
                   1100:     uhub*   at uhub? port ? configuration ? interface ?
1.5       mspo     1101: 
1.4       mspo     1102:     # USB Mass Storage
                   1103:     umass*  at uhub? port ? configuration ? interface ?
                   1104:     wd*     at umass?
                   1105:     # SCSI controllers
                   1106:     ahc*    at pci? dev ? function ?        # Adaptec [23]94x, aic78x0 SCSI
1.5       mspo     1107: 
1.4       mspo     1108:     # SCSI bus support (for both ahc and umass)
                   1109:     scsibus* at scsi?
1.5       mspo     1110: 
1.4       mspo     1111:     # SCSI devices
                   1112:     sd*     at scsibus? target ? lun ?      # SCSI disk drives
                   1113:     cd*     at scsibus? target ? lun ?      # SCSI CD-ROM drives
1.1       mspo     1114: 
                   1115: 
1.28      gdt      1116: NetBSD as a domU in a VPS
                   1117: =========================
                   1118: 
                   1119: The bulk of the HOWTO is about using NetBSD as a dom0 on your own
                   1120: hardware.  This section explains how to deal with Xen in a domU as a
                   1121: virtual private server where you do not control or have access to the
                   1122: dom0.
                   1123: 
                   1124: TODO: Perhaps reference panix, prmgr, amazon as interesting examples.
                   1125: 
                   1126: TODO: Somewhere, discuss pvgrub and py-grub to load the domU kernel
                   1127: from the domU filesystem.
1.44      gdt      1128: 
                   1129: Using npf
                   1130: ---------
                   1131: 
                   1132: In standard kernels, npf is a module, and thus cannot be loadeed in a
                   1133: DOMU kernel.
                   1134: 
                   1135: TODO: explain how to compile npf into a custom kernel, answering:
                   1136: http://mail-index.netbsd.org/netbsd-users/2014/12/26/msg015576.html

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