Annotation of wikisrc/ports/xen/howto.mdwn, revision 1.31

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: 
        !           285:        xend=YES
        !           286:        xenbackendd=YES
        !           287: 
        !           288: For 4.1 (and thus xm), add to rc.conf:
        !           289: 
        !           290:         xend=YES
        !           291:         xencommons=YES
        !           292: 
        !           293: TODO: Explain why if xm is preferred on 4.1, rc.d/xendomains has xl.
        !           294: 
        !           295: For 4.2 with xl, add to rc.conf:
        !           296: 
        !           297:         TODO: explain if there is a xend replacement
        !           298:         xencommons=YES
        !           299: 
        !           300: TODO: Recommend for/against xen-watchdog.
1.27      jnemeth   301: 
1.15      gdt       302: Updating NetBSD in a dom0
                    303: -------------------------
                    304: 
                    305: This is just like updating NetBSD on bare hardware, assuming the new
                    306: version supports the version of Xen you are running.  Generally, one
                    307: replaces the kernel and reboots, and then overlays userland binaries
                    308: and adjusts /etc.
                    309: 
                    310: Note that one must update both the non-Xen kernel typically used for
                    311: rescue purposes and the DOM0 kernel used with Xen.
                    312: 
1.22      gdt       313: To convert from grub to /boot, install an mbr bootblock with fdisk,
                    314: bootxx_ with installboot, /boot and /boot.cfg.  This really should be
                    315: no different than completely reinstalling boot blocks on a non-Xen
                    316: system.
                    317: 
1.15      gdt       318: Updating Xen versions
                    319: ---------------------
                    320: 
1.21      gdt       321: Updating Xen is conceptually not difficult, but can run into all the
                    322: issues found when installing Xen.  Assuming migration from 4.1 to 4.2,
                    323: remove the xenkernel41 and xentools41 packages and install the
                    324: xenkernel42 and xentools42 packages.  Copy the 4.2 xen.gz to /.
                    325: 
                    326: Ensure that the contents of /etc/rc.d/xen* are correct.  Enable the
                    327: correct set of daemons.  Ensure that the domU config files are valid
                    328: for the new version.
1.15      gdt       329: 
1.28      gdt       330: 
                    331: Unprivileged domains (domU)
                    332: ===========================
                    333: 
                    334: This section describes general concepts about domUs.  It does not
                    335: address specific domU operating systems or how to install them.
                    336: 
                    337: Provided Resources for PV domains
                    338: ---------------------------------
                    339: 
                    340: TODO: Explain that domUs get cpu, memory, disk and network.
                    341: Explain that randomness can be an issue.
                    342: 
                    343: Virtual disks
                    344: -------------
                    345: 
                    346: TODO: Explain how to set up files for vnd and that one should write all zeros to preallocate.
                    347: TODO: Explain in what NetBSD versions sparse vnd files do and don't work.
                    348: 
                    349: Virtual Networking
                    350: ------------------
                    351: 
                    352: TODO: explain xvif concept, and that it's general.
                    353: 
                    354: There are two normal styles: bridging and NAT.
                    355: 
                    356: With bridging, the domU perceives itself to be on the same network as
                    357: the dom0.  For server virtualization, this is usually best.
                    358: 
                    359: With NAT, the domU perceives itself to be behind a NAT running on the
                    360: dom0.  This is often appropriate when running Xen on a workstation.
                    361: 
                    362: One can construct arbitrary other configurations, but there is no
                    363: script support.
                    364: 
                    365: Config files
                    366: ------------
                    367: 
                    368: TODO: give example config files.   Use both lvm and vnd.
                    369: 
                    370: TODO: explain the mess with 3 arguments for disks and how to cope (0x1).
                    371: 
                    372: Starting domains
                    373: ----------------
                    374: 
                    375: TODO: Explain "xm start" and "xl start".  Explain rc.d/xendomains.
                    376: 
                    377: TODO: Explain why 4.1 rc.d/xendomains has xl, when one should use xm
                    378: on 4.1.
                    379: 
                    380: Creating specific unprivileged domains (domU)
                    381: =============================================
1.14      gdt       382: 
                    383: Creating domUs is almost entirely independent of operating system.  We
                    384: first explain NetBSD, and then differences for Linux and Solaris.
                    385: 
                    386: Creating an unprivileged NetBSD domain (domU)
                    387: ---------------------------------------------
1.1       mspo      388: 
                    389: Once you have *domain0* running, you need to start the xen tool daemon
1.5       mspo      390: (`/usr/pkg/share/examples/rc.d/xend start`) and the xen backend daemon
                    391: (`/usr/pkg/share/examples/rc.d/xenbackendd start` for Xen3\*,
                    392: `/usr/pkg/share/examples/rc.d/xencommons start` for Xen4.\*). Make sure
                    393: that `/dev/xencons` and `/dev/xenevt` exist before starting `xend`. You
                    394: can create them with this command:
1.1       mspo      395: 
1.3       mspo      396:     # cd /dev && sh MAKEDEV xen
1.1       mspo      397: 
1.5       mspo      398: xend will write logs to `/var/log/xend.log` and
                    399: `/var/log/xend-debug.log`. You can then control xen with the xm tool.
                    400: 'xm list' will show something like:
1.1       mspo      401: 
1.3       mspo      402:     # xm list
                    403:     Name              Id  Mem(MB)  CPU  State  Time(s)  Console
                    404:     Domain-0           0       64    0  r----     58.1
1.1       mspo      405: 
                    406: 'xm create' allows you to create a new domain. It uses a config file in
                    407: PKG\_SYSCONFDIR for its parameters. By default, this file will be in
1.5       mspo      408: `/usr/pkg/etc/xen/`. On creation, a kernel has to be specified, which
                    409: will be executed in the new domain (this kernel is in the *domain0* file
                    410: system, not on the new domain virtual disk; but please note, you should
                    411: install the same kernel into *domainU* as `/netbsd` in order to make
1.27      jnemeth   412: your system tools, like savecore(8), work). A suitable kernel is
1.5       mspo      413: provided as part of the i386 and amd64 binary sets: XEN3\_DOMU.
1.1       mspo      414: 
                    415: Here is an /usr/pkg/etc/xen/nbsd example config file:
                    416: 
1.3       mspo      417:     #  -*- mode: python; -*-
                    418:     #============================================================================
                    419:     # Python defaults setup for 'xm create'.
                    420:     # Edit this file to reflect the configuration of your system.
                    421:     #============================================================================
1.5       mspo      422: 
1.3       mspo      423:     #----------------------------------------------------------------------------
                    424:     # Kernel image file. This kernel will be loaded in the new domain.
                    425:     kernel = "/home/bouyer/netbsd-XEN3_DOMU"
                    426:     #kernel = "/home/bouyer/netbsd-INSTALL_XEN3_DOMU"
1.5       mspo      427: 
1.3       mspo      428:     # Memory allocation (in megabytes) for the new domain.
                    429:     memory = 128
1.5       mspo      430: 
1.3       mspo      431:     # A handy name for your new domain. This will appear in 'xm list',
                    432:     # and you can use this as parameters for xm in place of the domain
                    433:     # number. All domains must have different names.
                    434:     #
                    435:     name = "nbsd"
1.5       mspo      436: 
1.3       mspo      437:     # The number of virtual CPUs this domain has.
                    438:     #
                    439:     vcpus = 1
1.5       mspo      440: 
1.3       mspo      441:     #----------------------------------------------------------------------------
                    442:     # Define network interfaces for the new domain.
1.5       mspo      443: 
1.3       mspo      444:     # Number of network interfaces (must be at least 1). Default is 1.
                    445:     nics = 1
1.5       mspo      446: 
1.3       mspo      447:     # Define MAC and/or bridge for the network interfaces.
                    448:     #
                    449:     # The MAC address specified in ``mac'' is the one used for the interface
                    450:     # in the new domain. The interface in domain0 will use this address XOR'd
                    451:     # with 00:00:00:01:00:00 (i.e. aa:00:00:51:02:f0 in our example). Random
                    452:     # MACs are assigned if not given.
                    453:     #
                    454:     # ``bridge'' is a required parameter, which will be passed to the
                    455:     # vif-script called by xend(8) when a new domain is created to configure
                    456:     # the new xvif interface in domain0.
                    457:     #
                    458:     # In this example, the xvif is added to bridge0, which should have been
                    459:     # set up prior to the new domain being created -- either in the
                    460:     # ``network'' script or using a /etc/ifconfig.bridge0 file.
                    461:     #
                    462:     vif = [ 'mac=aa:00:00:50:02:f0, bridge=bridge0' ]
1.5       mspo      463: 
1.3       mspo      464:     #----------------------------------------------------------------------------
                    465:     # Define the disk devices you want the domain to have access to, and
                    466:     # what you want them accessible as.
                    467:     #
                    468:     # Each disk entry is of the form:
                    469:     #
1.5       mspo      470:     #   phy:DEV,VDEV,MODE
1.3       mspo      471:     #
                    472:     # where DEV is the device, VDEV is the device name the domain will see,
                    473:     # and MODE is r for read-only, w for read-write.  You can also create
                    474:     # file-backed domains using disk entries of the form:
                    475:     #
1.5       mspo      476:     #   file:PATH,VDEV,MODE
1.3       mspo      477:     #
                    478:     # where PATH is the path to the file used as the virtual disk, and VDEV
                    479:     # and MODE have the same meaning as for ``phy'' devices.
                    480:     #
                    481:     # VDEV doesn't really matter for a NetBSD guest OS (it's just used as an index),
                    482:     # but it does for Linux.
                    483:     # Worse, the device has to exist in /dev/ of domain0, because xm will
                    484:     # try to stat() it. This means that in order to load a Linux guest OS
                    485:     # from a NetBSD domain0, you'll have to create /dev/hda1, /dev/hda2, ...
                    486:     # on domain0, with the major/minor from Linux :(
                    487:     # Alternatively it's possible to specify the device number in hex,
                    488:     # e.g. 0x301 for /dev/hda1, 0x302 for /dev/hda2, etc ...
1.5       mspo      489: 
1.3       mspo      490:     disk = [ 'phy:/dev/wd0e,0x1,w' ]
                    491:     #disk = [ 'file:/var/xen/nbsd-disk,0x01,w' ]
                    492:     #disk = [ 'file:/var/xen/nbsd-disk,0x301,w' ]
1.5       mspo      493: 
1.3       mspo      494:     #----------------------------------------------------------------------------
                    495:     # Set the kernel command line for the new domain.
1.5       mspo      496: 
1.3       mspo      497:     # Set root device. This one does matter for NetBSD
                    498:     root = "xbd0"
                    499:     # extra parameters passed to the kernel
                    500:     # this is where you can set boot flags like -s, -a, etc ...
                    501:     #extra = ""
1.5       mspo      502: 
1.3       mspo      503:     #----------------------------------------------------------------------------
                    504:     # Set according to whether you want the domain restarted when it exits.
                    505:     # The default is False.
                    506:     #autorestart = True
1.5       mspo      507: 
1.3       mspo      508:     # end of nbsd config file ====================================================
1.1       mspo      509: 
                    510: When a new domain is created, xen calls the
1.5       mspo      511: `/usr/pkg/etc/xen/vif-bridge` script for each virtual network interface
                    512: created in *domain0*. This can be used to automatically configure the
                    513: xvif?.? interfaces in *domain0*. In our example, these will be bridged
                    514: with the bridge0 device in *domain0*, but the bridge has to exist first.
                    515: To do this, create the file `/etc/ifconfig.bridge0` and make it look
                    516: like this:
1.1       mspo      517: 
1.3       mspo      518:     create
                    519:     !brconfig $int add ex0 up
1.1       mspo      520: 
1.5       mspo      521: (replace `ex0` with the name of your physical interface). Then bridge0
1.27      jnemeth   522: will be created on boot. See the bridge(4) man page for details.
1.1       mspo      523: 
1.5       mspo      524: So, here is a suitable `/usr/pkg/etc/xen/vif-bridge` for xvif?.? (a
                    525: working vif-bridge is also provided with xentools20) configuring:
1.1       mspo      526: 
1.5       mspo      527:     #!/bin/sh
1.3       mspo      528:     #============================================================================
1.31    ! gdt       529:     # $NetBSD: howto.mdwn,v 1.30 2014/12/24 15:21:41 gdt Exp $
1.3       mspo      530:     #
                    531:     # /usr/pkg/etc/xen/vif-bridge
                    532:     #
                    533:     # Script for configuring a vif in bridged mode with a dom0 interface.
                    534:     # The xend(8) daemon calls a vif script when bringing a vif up or down.
                    535:     # The script name to use is defined in /usr/pkg/etc/xen/xend-config.sxp
                    536:     # in the ``vif-script'' field.
                    537:     #
                    538:     # Usage: vif-bridge up|down [var=value ...]
                    539:     #
                    540:     # Actions:
1.5       mspo      541:     #    up     Adds the vif interface to the bridge.
                    542:     #    down   Removes the vif interface from the bridge.
1.3       mspo      543:     #
                    544:     # Variables:
1.5       mspo      545:     #    domain name of the domain the interface is on (required).
                    546:     #    vifq   vif interface name (required).
                    547:     #    mac    vif MAC address (required).
                    548:     #    bridge bridge to add the vif to (required).
1.3       mspo      549:     #
                    550:     # Example invocation:
                    551:     #
                    552:     # vif-bridge up domain=VM1 vif=xvif1.0 mac="ee:14:01:d0:ec:af" bridge=bridge0
                    553:     #
                    554:     #============================================================================
1.5       mspo      555: 
1.3       mspo      556:     # Exit if anything goes wrong
                    557:     set -e
1.5       mspo      558: 
1.3       mspo      559:     echo "vif-bridge $*"
1.5       mspo      560: 
1.3       mspo      561:     # Operation name.
                    562:     OP=$1; shift
1.5       mspo      563: 
1.3       mspo      564:     # Pull variables in args into environment
                    565:     for arg ; do export "${arg}" ; done
1.5       mspo      566: 
1.3       mspo      567:     # Required parameters. Fail if not set.
                    568:     domain=${domain:?}
                    569:     vif=${vif:?}
                    570:     mac=${mac:?}
                    571:     bridge=${bridge:?}
1.5       mspo      572: 
1.3       mspo      573:     # Optional parameters. Set defaults.
                    574:     ip=${ip:-''}   # default to null (do nothing)
1.5       mspo      575: 
1.3       mspo      576:     # Are we going up or down?
                    577:     case $OP in
1.5       mspo      578:     up) brcmd='add' ;;
1.3       mspo      579:     down)   brcmd='delete' ;;
                    580:     *)
1.5       mspo      581:         echo 'Invalid command: ' $OP
                    582:         echo 'Valid commands are: up, down'
                    583:         exit 1
                    584:         ;;
1.3       mspo      585:     esac
1.5       mspo      586: 
1.3       mspo      587:     # Don't do anything if the bridge is "null".
                    588:     if [ "${bridge}" = "null" ] ; then
1.5       mspo      589:         exit
1.3       mspo      590:     fi
1.5       mspo      591: 
1.3       mspo      592:     # Don't do anything if the bridge doesn't exist.
                    593:     if ! ifconfig -l | grep "${bridge}" >/dev/null; then
1.5       mspo      594:         exit
1.3       mspo      595:     fi
1.5       mspo      596: 
1.3       mspo      597:     # Add/remove vif to/from bridge.
                    598:     ifconfig x${vif} $OP
                    599:     brconfig ${bridge} ${brcmd} x${vif}
1.1       mspo      600: 
                    601: Now, running
                    602: 
1.3       mspo      603:     xm create -c /usr/pkg/etc/xen/nbsd
1.1       mspo      604: 
1.5       mspo      605: should create a domain and load a NetBSD kernel in it. (Note: `-c`
                    606: causes xm to connect to the domain's console once created.) The kernel
                    607: will try to find its root file system on xbd0 (i.e., wd0e) which hasn't
                    608: been created yet. wd0e will be seen as a disk device in the new domain,
                    609: so it will be 'sub-partitioned'. We could attach a ccd to wd0e in
                    610: *domain0* and partition it, newfs and extract the NetBSD/i386 or amd64
                    611: tarballs there, but there's an easier way: load the
                    612: `netbsd-INSTALL_XEN3_DOMU` kernel provided in the NetBSD binary sets.
                    613: Like other install kernels, it contains a ramdisk with sysinst, so you
                    614: can install NetBSD using sysinst on your new domain.
1.1       mspo      615: 
                    616: If you want to install NetBSD/Xen with a CDROM image, the following line
1.5       mspo      617: should be used in the `/usr/pkg/etc/xen/nbsd` file:
1.1       mspo      618: 
1.3       mspo      619:     disk = [ 'phy:/dev/wd0e,0x1,w', 'phy:/dev/cd0a,0x2,r' ]
1.1       mspo      620: 
                    621: After booting the domain, the option to install via CDROM may be
1.5       mspo      622: selected. The CDROM device should be changed to `xbd1d`.
1.1       mspo      623: 
1.5       mspo      624: Once done installing, `halt -p` the new domain (don't reboot or halt, it
                    625: would reload the INSTALL\_XEN3\_DOMU kernel even if you changed the
1.1       mspo      626: config file), switch the config file back to the XEN3\_DOMU kernel, and
1.5       mspo      627: start the new domain again. Now it should be able to use `root on xbd0a`
                    628: and you should have a second, functional NetBSD system on your xen
                    629: installation.
1.1       mspo      630: 
                    631: When the new domain is booting you'll see some warnings about *wscons*
                    632: and the pseudo-terminals. These can be fixed by editing the files
1.5       mspo      633: `/etc/ttys` and `/etc/wscons.conf`. You must disable all terminals in
                    634: `/etc/ttys`, except *console*, like this:
1.1       mspo      635: 
1.3       mspo      636:     console "/usr/libexec/getty Pc"         vt100   on secure
                    637:     ttyE0   "/usr/libexec/getty Pc"         vt220   off secure
                    638:     ttyE1   "/usr/libexec/getty Pc"         vt220   off secure
                    639:     ttyE2   "/usr/libexec/getty Pc"         vt220   off secure
                    640:     ttyE3   "/usr/libexec/getty Pc"         vt220   off secure
1.1       mspo      641: 
1.5       mspo      642: Finally, all screens must be commented out from `/etc/wscons.conf`.
1.1       mspo      643: 
                    644: It is also desirable to add
                    645: 
1.3       mspo      646:     powerd=YES
1.1       mspo      647: 
1.5       mspo      648: in rc.conf. This way, the domain will be properly shut down if
                    649: `xm shutdown -R` or `xm shutdown -H` is used on the domain0.
1.1       mspo      650: 
                    651: Your domain should be now ready to work, enjoy.
                    652: 
1.14      gdt       653: Creating an unprivileged Linux domain (domU)
1.5       mspo      654: --------------------------------------------
1.1       mspo      655: 
                    656: Creating unprivileged Linux domains isn't much different from
                    657: unprivileged NetBSD domains, but there are some details to know.
                    658: 
                    659: First, the second parameter passed to the disk declaration (the '0x1' in
                    660: the example below)
                    661: 
1.3       mspo      662:     disk = [ 'phy:/dev/wd0e,0x1,w' ]
1.1       mspo      663: 
                    664: does matter to Linux. It wants a Linux device number here (e.g. 0x300
                    665: for hda). Linux builds device numbers as: (major \<\< 8 + minor). So,
                    666: hda1 which has major 3 and minor 1 on a Linux system will have device
                    667: number 0x301. Alternatively, devices names can be used (hda, hdb, ...)
                    668: as xentools has a table to map these names to devices numbers. To export
                    669: a partition to a Linux guest we can use:
                    670: 
1.3       mspo      671:     disk = [ 'phy:/dev/wd0e,0x300,w' ]
                    672:     root = "/dev/hda1 ro"
1.1       mspo      673: 
                    674: and it will appear as /dev/hda on the Linux system, and be used as root
                    675: partition.
                    676: 
                    677: To install the Linux system on the partition to be exported to the guest
                    678: domain, the following method can be used: install sysutils/e2fsprogs
                    679: from pkgsrc. Use mke2fs to format the partition that will be the root
                    680: partition of your Linux domain, and mount it. Then copy the files from a
1.5       mspo      681: working Linux system, make adjustments in `/etc` (fstab, network
                    682: config). It should also be possible to extract binary packages such as
                    683: .rpm or .deb directly to the mounted partition using the appropriate
                    684: tool, possibly running under NetBSD's Linux emulation. Once the
                    685: filesystem has been populated, umount it. If desirable, the filesystem
                    686: can be converted to ext3 using tune2fs -j. It should now be possible to
                    687: boot the Linux guest domain, using one of the vmlinuz-\*-xenU kernels
                    688: available in the Xen binary distribution.
1.1       mspo      689: 
                    690: To get the linux console right, you need to add:
                    691: 
1.3       mspo      692:     extra = "xencons=tty1"
1.1       mspo      693: 
                    694: to your configuration since not all linux distributions auto-attach a
                    695: tty to the xen console.
                    696: 
1.14      gdt       697: Creating an unprivileged Solaris domain (domU)
1.5       mspo      698: ----------------------------------------------
1.1       mspo      699: 
                    700: Download an Opensolaris [release](http://opensolaris.org/os/downloads/)
                    701: or [development snapshot](http://genunix.org/) DVD image. Attach the DVD
1.5       mspo      702: image to a MAN.VND.4 device. Copy the kernel and ramdisk filesystem
                    703: image to your dom0 filesystem.
1.1       mspo      704: 
1.3       mspo      705:     dom0# mkdir /root/solaris
                    706:     dom0# vnconfig vnd0 osol-1002-124-x86.iso
                    707:     dom0# mount /dev/vnd0a /mnt
1.5       mspo      708: 
1.3       mspo      709:     ## for a 64-bit guest
                    710:     dom0# cp /mnt/boot/amd64/x86.microroot /root/solaris
                    711:     dom0# cp /mnt/platform/i86xpv/kernel/amd64/unix /root/solaris
1.5       mspo      712: 
1.3       mspo      713:     ## for a 32-bit guest
                    714:     dom0# cp /mnt/boot/x86.microroot /root/solaris
                    715:     dom0# cp /mnt/platform/i86xpv/kernel/unix /root/solaris
1.5       mspo      716: 
1.3       mspo      717:     dom0# umount /mnt
1.5       mspo      718:           
                    719: 
                    720: Keep the MAN.VND.4 configured. For some reason the boot process stalls
                    721: unless the DVD image is attached to the guest as a "phy" device. Create
                    722: an initial configuration file with the following contents. Substitute
                    723: */dev/wd0k* with an empty partition at least 8 GB large.
1.1       mspo      724: 
1.4       mspo      725:     memory = 640
                    726:     name = 'solaris'
                    727:     disk = [ 'phy:/dev/wd0k,0,w' ]
                    728:     disk += [ 'phy:/dev/vnd0d,6:cdrom,r' ]
                    729:     vif = [ 'bridge=bridge0' ]
                    730:     kernel = '/root/solaris/unix'
                    731:     ramdisk = '/root/solaris/x86.microroot'
                    732:     # for a 64-bit guest
                    733:     extra = '/platform/i86xpv/kernel/amd64/unix - nowin -B install_media=cdrom'
                    734:     # for a 32-bit guest
                    735:     #extra = '/platform/i86xpv/kernel/unix - nowin -B install_media=cdrom'
1.5       mspo      736:           
                    737: 
1.1       mspo      738: Start the guest.
                    739: 
1.4       mspo      740:     dom0# xm create -c solaris.cfg
                    741:     Started domain solaris
                    742:                           v3.3.2 chgset 'unavailable'
                    743:     SunOS Release 5.11 Version snv_124 64-bit
                    744:     Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.
                    745:     Use is subject to license terms.
                    746:     Hostname: opensolaris
                    747:     Remounting root read/write
                    748:     Probing for device nodes ...
                    749:     WARNING: emlxs: ddi_modopen drv/fct failed: err 2
                    750:     Preparing live image for use
                    751:     Done mounting Live image
1.5       mspo      752:           
1.1       mspo      753: 
                    754: Make sure the network is configured. Note that it can take a minute for
                    755: the xnf0 interface to appear.
                    756: 
1.4       mspo      757:     opensolaris console login: jack
                    758:     Password: jack
                    759:     Sun Microsystems Inc.   SunOS 5.11      snv_124 November 2008
                    760:     jack@opensolaris:~$ pfexec sh
                    761:     sh-3.2# ifconfig -a
                    762:     sh-3.2# exit
1.5       mspo      763:           
1.1       mspo      764: 
                    765: Set a password for VNC and start the VNC server which provides the X11
                    766: display where the installation program runs.
                    767: 
1.4       mspo      768:     jack@opensolaris:~$ vncpasswd
                    769:     Password: solaris
                    770:     Verify: solaris
                    771:     jack@opensolaris:~$ cp .Xclients .vnc/xstartup
                    772:     jack@opensolaris:~$ vncserver :1
1.5       mspo      773:           
1.1       mspo      774: 
1.5       mspo      775: From a remote machine connect to the VNC server. Use `ifconfig xnf0` on
                    776: the guest to find the correct IP address to use.
1.1       mspo      777: 
1.4       mspo      778:     remote$ vncviewer 172.18.2.99:1
1.5       mspo      779:           
1.1       mspo      780: 
                    781: It is also possible to launch the installation on a remote X11 display.
                    782: 
1.4       mspo      783:     jack@opensolaris:~$ export DISPLAY=172.18.1.1:0
                    784:     jack@opensolaris:~$ pfexec gui-install
1.5       mspo      785:            
1.1       mspo      786: 
                    787: After the GUI installation is complete you will be asked to reboot.
                    788: Before that you need to determine the ZFS ID for the new boot filesystem
                    789: and update the configuration file accordingly. Return to the guest
                    790: console.
                    791: 
1.4       mspo      792:     jack@opensolaris:~$ pfexec zdb -vvv rpool | grep bootfs
                    793:                     bootfs = 43
                    794:     ^C
                    795:     jack@opensolaris:~$
1.5       mspo      796:            
1.1       mspo      797: 
                    798: The final configuration file should look like this. Note in particular
                    799: the last line.
                    800: 
1.4       mspo      801:     memory = 640
                    802:     name = 'solaris'
                    803:     disk = [ 'phy:/dev/wd0k,0,w' ]
                    804:     vif = [ 'bridge=bridge0' ]
                    805:     kernel = '/root/solaris/unix'
                    806:     ramdisk = '/root/solaris/x86.microroot'
                    807:     extra = '/platform/i86xpv/kernel/amd64/unix -B zfs-bootfs=rpool/43,bootpath="/xpvd/xdf@0:a"'
1.5       mspo      808:            
1.1       mspo      809: 
                    810: Restart the guest to verify it works correctly.
                    811: 
1.4       mspo      812:     dom0# xm destroy solaris
                    813:     dom0# xm create -c solaris.cfg
                    814:     Using config file "./solaris.cfg".
                    815:     v3.3.2 chgset 'unavailable'
                    816:     Started domain solaris
                    817:     SunOS Release 5.11 Version snv_124 64-bit
                    818:     Copyright 1983-2009 Sun Microsystems, Inc.  All rights reserved.
                    819:     Use is subject to license terms.
                    820:     WARNING: emlxs: ddi_modopen drv/fct failed: err 2
                    821:     Hostname: osol
                    822:     Configuring devices.
                    823:     Loading smf(5) service descriptions: 160/160
                    824:     svccfg import warnings. See /var/svc/log/system-manifest-import:default.log .
                    825:     Reading ZFS config: done.
                    826:     Mounting ZFS filesystems: (6/6)
                    827:     Creating new rsa public/private host key pair
                    828:     Creating new dsa public/private host key pair
1.5       mspo      829: 
1.4       mspo      830:     osol console login:
1.5       mspo      831:            
1.1       mspo      832: 
                    833: Using PCI devices in guest domains
1.14      gdt       834: ----------------------------------
1.1       mspo      835: 
                    836: The domain0 can give other domains access to selected PCI devices. This
                    837: can allow, for example, a non-privileged domain to have access to a
                    838: physical network interface or disk controller. However, keep in mind
                    839: that giving a domain access to a PCI device most likely will give the
                    840: domain read/write access to the whole physical memory, as PCs don't have
                    841: an IOMMU to restrict memory access to DMA-capable device. Also, it's not
                    842: possible to export ISA devices to non-domain0 domains (which means that
                    843: the primary VGA adapter can't be exported. A guest domain trying to
                    844: access the VGA registers will panic).
                    845: 
                    846: This functionality is only available in NetBSD-5.1 (and later) domain0
                    847: and domU. If the domain0 is NetBSD, it has to be running Xen 3.1, as
                    848: support has not been ported to later versions at this time.
                    849: 
                    850: For a PCI device to be exported to a domU, is has to be attached to the
1.5       mspo      851: `pciback` driver in domain0. Devices passed to the domain0 via the
                    852: pciback.hide boot parameter will attach to `pciback` instead of the
                    853: usual driver. The list of devices is specified as `(bus:dev.func)`,
                    854: where bus and dev are 2-digit hexadecimal numbers, and func a
                    855: single-digit number:
1.1       mspo      856: 
1.4       mspo      857:     pciback.hide=(00:0a.0)(00:06.0)
1.1       mspo      858: 
                    859: pciback devices should show up in the domain0's boot messages, and the
1.5       mspo      860: devices should be listed in the `/kern/xen/pci` directory.
1.1       mspo      861: 
1.5       mspo      862: PCI devices to be exported to a domU are listed in the `pci` array of
                    863: the domU's config file, with the format `'0000:bus:dev.func'`
1.1       mspo      864: 
1.4       mspo      865:     pci = [ '0000:00:06.0', '0000:00:0a.0' ]
1.1       mspo      866: 
1.5       mspo      867: In the domU an `xpci` device will show up, to which one or more pci
                    868: busses will attach. Then the PCI drivers will attach to PCI busses as
                    869: usual. Note that the default NetBSD DOMU kernels do not have `xpci` or
                    870: any PCI drivers built in by default; you have to build your own kernel
                    871: to use PCI devices in a domU. Here's a kernel config example:
1.1       mspo      872: 
1.4       mspo      873:     include         "arch/i386/conf/XEN3_DOMU"
                    874:     #include         "arch/i386/conf/XENU"           # in NetBSD 3.0
1.5       mspo      875: 
1.4       mspo      876:     # Add support for PCI busses to the XEN3_DOMU kernel
                    877:     xpci* at xenbus ?
                    878:     pci* at xpci ?
1.5       mspo      879: 
1.4       mspo      880:     # Now add PCI and related devices to be used by this domain
                    881:     # USB Controller and Devices
1.5       mspo      882: 
1.4       mspo      883:     # PCI USB controllers
                    884:     uhci*   at pci? dev ? function ?        # Universal Host Controller (Intel)
1.5       mspo      885: 
1.4       mspo      886:     # USB bus support
                    887:     usb*    at uhci?
1.5       mspo      888: 
1.4       mspo      889:     # USB Hubs
                    890:     uhub*   at usb?
                    891:     uhub*   at uhub? port ? configuration ? interface ?
1.5       mspo      892: 
1.4       mspo      893:     # USB Mass Storage
                    894:     umass*  at uhub? port ? configuration ? interface ?
                    895:     wd*     at umass?
                    896:     # SCSI controllers
                    897:     ahc*    at pci? dev ? function ?        # Adaptec [23]94x, aic78x0 SCSI
1.5       mspo      898: 
1.4       mspo      899:     # SCSI bus support (for both ahc and umass)
                    900:     scsibus* at scsi?
1.5       mspo      901: 
1.4       mspo      902:     # SCSI devices
                    903:     sd*     at scsibus? target ? lun ?      # SCSI disk drives
                    904:     cd*     at scsibus? target ? lun ?      # SCSI CD-ROM drives
1.1       mspo      905: 
                    906: 
1.28      gdt       907: NetBSD as a domU in a VPS
                    908: =========================
                    909: 
                    910: The bulk of the HOWTO is about using NetBSD as a dom0 on your own
                    911: hardware.  This section explains how to deal with Xen in a domU as a
                    912: virtual private server where you do not control or have access to the
                    913: dom0.
                    914: 
                    915: TODO: Perhaps reference panix, prmgr, amazon as interesting examples.
                    916: 
                    917: TODO: Somewhere, discuss pvgrub and py-grub to load the domU kernel
                    918: from the domU filesystem.

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