1: Introduction
2: ============
3:
4: [![[Xen
5: screenshot]](http://www.netbsd.org/gallery/in-Action/hubertf-xens.png)](../../gallery/in-Action/hubertf-xen.png)
6:
7: Xen is a virtual machine monitor or hypervisor for x86 hardware
8: (i686-class or higher), which supports running multiple guest
9: operating systems on a single physical machine. With Xen, one uses
10: the Xen kernel to control the CPU, memory and console, a dom0
11: operating system which mediates access to other hardware (e.g., disks,
12: network, USB), and one or more domU operating systems which operate in
13: an unprivileged virtualized environment. IO requests from the domU
14: systems are forwarded by the hypervisor (Xen) to the dom0 to be
15: fulfilled.
16:
17: Xen supports two styles of guests. The original is Para-Virtualized
18: (PV) which means that the guest OS does not attempt to access hardware
19: directly, but instead makes hypercalls to the hypervisor. This is
20: analogous to a user-space program making system calls. (The dom0
21: operating system uses PV calls for some functions, such as updating
22: memory mapping page tables, but has direct hardware access for disk
23: and network.) PV guests must be specifically coded for Xen.
24:
25: The more recent style is HVM, which means that the guest does not have
26: code for Xen and need not be aware that it is running under Xen.
27: Attempts to access hardware registers are trapped and emulated. This
28: style is less efficient but can run unmodified guests.
29:
30: Generally any amd64 machine will work with Xen and PV guests. In
31: theory i386 computers without amd64 support can be used for Xen <=
32: 4.2, but we have no recent reports of this working (this is a hint).
33: For HVM guests, the VT or VMX cpu feature (Intel) or SVM/HVM/VT
34: (amd64) is needed; "cpuctl identify 0" will show this. TODO: Clean up
35: and check the above features.
36:
37: At boot, the dom0 kernel is loaded as a module with Xen as the kernel.
38: The dom0 can start one or more domUs. (Booting is explained in detail
39: in the dom0 section.)
40:
41: NetBSD supports Xen in that it can serve as dom0, be used as a domU,
42: and that Xen kernels and tools are available in pkgsrc. This HOWTO
43: attempts to address both the case of running a NetBSD dom0 on hardware
44: and running domUs under it (NetBSD and other), and also running NetBSD
45: as a domU in a VPS.
46:
47: Some versions of Xen support "PCI passthrough", which means that
48: specific PCI devices can be made available to a specific domU instead
49: of the dom0. This can be useful to let a domU run X11, or access some
50: network interface or other peripheral.
51:
52: Prerequisites
53: -------------
54:
55: Installing NetBSD/Xen is not extremely difficult, but it is more
56: complex than a normal installation of NetBSD.
57: In general, this HOWTO is occasionally overly restrictive about how
58: things must be done, guiding the reader to stay on the established
59: path when there are no known good reasons to stray.
60:
61: This HOWTO presumes a basic familiarity with the Xen system
62: architecture. This HOWTO presumes familiarity with installing NetBSD
63: on i386/amd64 hardware and installing software from pkgsrc.
64: See also the [Xen website](http://www.xenproject.org/).
65:
66: History
67: -------
68:
69: NetBSD used to support Xen2; this has been removed.
70:
71: Before NetBSD's native bootloader could support Xen, the use of
72: grub was recommended. If necessary, see the
73: [old grub information](/ports/xen/howto-grub/).
74:
75: Versions of Xen and NetBSD
76: ==========================
77:
78: Most of the installation concepts and instructions are independent
79: of Xen version and NetBSD version. This section gives advice on
80: which version to choose. Versions not in pkgsrc and older unsupported
81: versions of NetBSD are intentionally ignored.
82:
83: Xen
84: ---
85:
86: In NetBSD, xen is provided in pkgsrc, via matching pairs of packages
87: xenkernel and xentools. We will refer only to the kernel versions,
88: but note that both packages must be installed together and must have
89: matching versions.
90:
91: xenkernel3 and xenkernel33 provide Xen 3.1 and 3.3. These no longer
92: receive security patches and should not be used. Xen 3.1 supports PCI
93: passthrough. Xen 3.1 supports non-PAE on i386.
94:
95: xenkernel41 provides Xen 4.1. This is no longer maintained by Xen,
96: but as of 2014-12 receives backported security patches. It is a
97: reasonable although trailing-edge choice.
98:
99: xenkernel42 provides Xen 4.2. This is maintained by Xen, but old as
100: of 2014-12.
101:
102: Ideally newer versions of Xen will be added to pkgsrc.
103:
104: Note that NetBSD support is called XEN3. It works with 3.1 through
105: 4.2 because the hypercall interface has been stable.
106:
107: Xen command program
108: -------------------
109:
110: Early Xen used a program called "xm" to manipulate the system from the
111: dom0. Starting in 4.1, a replacement program with similar behavior
112: called "xl" is provided. In 4.2 and later, "xl" is preferred. 4.4 is
113: the last version that has "xm".
114:
115: NetBSD
116: ------
117:
118: The netbsd-5, netbsd-6, netbsd-7, and -current branches are all
119: reasonable choices, with more or less the same considerations for
120: non-Xen use. Therefore, netbsd-6 is recommended as the stable version
121: of the most recent release for production use. For those wanting to
122: learn Xen or without production stability concerns, netbsd-7 is likely
123: most appropriate.
124:
125: As of NetBSD 6, a NetBSD domU will support multiple vcpus. There is
126: no SMP support for NetBSD as dom0. (The dom0 itself doesn't really
127: need SMP; the lack of support is really a problem when using a dom0 as
128: a normal computer.)
129:
130: Architecture
131: ------------
132:
133: Xen itself can run on i386 or amd64 machines. (Practically, almost
134: any computer where one would want to run Xen supports amd64.) If
135: using an i386 NetBSD kernel for the dom0, PAE is required (PAE
136: versions are built by default). While i386 dom0 works fine, amd64 is
137: recommended as more normal.
138:
139: Xen 4.2 is the last version to support i386 as a host. TODO: Clarify
140: if this is about the CPU having to be amd64, or about the dom0 kernel
141: having to be amd64.
142:
143: One can then run i386 domUs and amd64 domUs, in any combination. If
144: running an i386 NetBSD kernel as a domU, the PAE version is required.
145: (Note that emacs (at least) fails if run on i386 with PAE when built
146: without, and vice versa, presumably due to bugs in the undump code.)
147:
148: Recommendation
149: --------------
150:
151: Therefore, this HOWTO recommends running xenkernel42 (and xentools42),
152: xl, the NetBSD 6 stable branch, and to use an amd64 kernel as the
153: dom0. Either the i386 or amd64 of NetBSD may be used as domUs.
154:
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:
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.
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.
183:
184: Styles of dom0 operation
185: ------------------------
186:
187: There are two basic ways to use Xen. The traditional method is for
188: the dom0 to do absolutely nothing other than providing support to some
189: number of domUs. Such a system was probably installed for the sole
190: purpose of hosting domUs, and sits in a server room on a UPS.
191:
192: The other way is to put Xen under a normal-usage computer, so that the
193: dom0 is what the computer would have been without Xen, perhaps a
194: desktop or laptop. Then, one can run domUs at will. Purists will
195: deride this as less secure than the previous approach, and for a
196: computer whose purpose is to run domUs, they are right. But Xen and a
197: dom0 (without domUs) is not meaingfully less secure than the same
198: things running without Xen. One can boot Xen or boot regular NetBSD
199: alternately with little problems, simply refraining from starting the
200: Xen daemons when not running Xen.
201:
202: Note that NetBSD as dom0 does not support multiple CPUs. This will
203: limit the performance of the Xen/dom0 workstation approach.
204:
205: Installation of NetBSD
206: ----------------------
207:
208: First,
209: [install NetBSD/amd64](/guide/inst/)
210: just as you would if you were not using Xen.
211: However, the partitioning approach is very important.
212:
213: If you want to use RAIDframe for the dom0, there are no special issues
214: for Xen. Typically one provides RAID storage for the dom0, and the
215: domU systems are unaware of RAID. The 2nd-stage loader bootxx_* skips
216: over a RAID1 header to find /boot from a filesystem within a RAID
217: partition; this is no different when booting Xen.
218:
219: There are 4 styles of providing backing storage for the virtual disks
220: used by domUs: raw partitions, LVM, file-backed vnd(4), and SAN,
221:
222: With raw partitions, one has a disklabel (or gpt) partition sized for
223: each virtual disk to be used by the domU. (If you are able to predict
224: how domU usage will evolve, please add an explanation to the HOWTO.
225: Seriously, needs tend to change over time.)
226:
227: One can use [lvm(8)](/guide/lvm/) to create logical devices to use
228: for domU disks. This is almost as efficient as raw disk partitions
229: and more flexible. Hence raw disk partitions should typically not
230: be used.
231:
232: One can use files in the dom0 filesystem, typically created by dd'ing
233: /dev/zero to create a specific size. This is somewhat less efficient,
234: but very convenient, as one can cp the files for backup, or move them
235: between dom0 hosts.
236:
237: Finally, in theory one can place the files backing the domU disks in a
238: SAN. (This is an invitation for someone who has done this to add a
239: HOWTO page.)
240:
241: Installation of Xen
242: -------------------
243:
244: In the dom0, install sysutils/xenkernel42 and sysutils/xentools42 from
245: pkgsrc (or another matching pair).
246: See [the pkgsrc
247: documentation](http://www.NetBSD.org/docs/pkgsrc/) for help with pkgsrc.
248:
249: For Xen 3.1, support for HVM guests is in sysutils/xentool3-hvm. More
250: recent versions have HVM support integrated in the main xentools
251: package. It is entirely reasonable to run only PV guests.
252:
253: Next you need to install the selected Xen kernel itself, which is
254: installed by pkgsrc as "/usr/pkg/xen*-kernel/xen.gz". Copy it to /.
255: For debugging, one may copy xen-debug.gz; this is conceptually similar
256: to DIAGNOSTIC and DEBUG in NetBSD. xen-debug.gz is basically only
257: useful with a serial console. Then, place a NetBSD XEN3_DOM0 kernel
258: in /, copied from releasedir/amd64/binary/kernel/netbsd-XEN3_DOM0.gz
259: of a NetBSD build. Both xen and NetBSD may be left compressed. (If
260: using i386, use releasedir/i386/binary/kernel/netbsd-XEN3PAE_DOM0.gz.)
261:
262: In a dom0 kernel, kernfs is mandatory for xend to comunicate with the
263: kernel, so ensure that /kern is in fstab.
264:
265: Because you already installed NetBSD, you have a working boot setup
266: with an MBR bootblock, either bootxx_ffsv1 or bootxx_ffsv2 at the
267: beginning of your root filesystem, /boot present, and likely
268: /boot.cfg. (If not, fix before continuing!)
269:
270: See boot.cfg(5) for an example. The basic line is
271:
272: "menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=256M"
273:
274: which specifies that the dom0 should have 256M, leaving the rest to be
275: allocated for domUs.
276:
277: As with non-Xen systems, you should have a line to boot /netbsd (a
278: kernel that works without Xen) and fallback versions of the non-Xen
279: kernel, Xen, and the dom0 kernel.
280:
281: The [HowTo on Installing into
282: RAID-1](http://mail-index.NetBSD.org/port-xen/2006/03/01/0010.html)
283: explains how to set up booting a dom0 with Xen using grub with
284: NetBSD's RAIDframe. (This is obsolete with the use of NetBSD's native
285: boot.)
286:
287: Configuring Xen
288: ---------------
289:
290: Now, you have a system that will boot Xen and the dom0 kernel, and
291: just run the dom0 kernel. There will be no domUs, and none can be
292: started because you still have to configure the dom0 tools. The
293: daemons which should be run vary with Xen version and with whether one
294: is using xm or xl. Note that xend is for supporting "xm", and should
295: only be used if you plan on using "xm". Do NOT enable xend if you
296: plan on using "xl" as it will cause problems.
297:
298: TODO: Give 3.1 advice (or remove it from pkgsrc).
299:
300: For 3.3 (and thus xm), add to rc.conf (but note that you should have
301: installed 4.1 or 4.2):
302:
303: xend=YES
304: xenbackendd=YES
305:
306: For 4.1 (and thus xm; xl is believed not to work well), add to rc.conf:
307:
308: xend=YES
309: xencommons=YES
310:
311: TODO: Explain why if xm is preferred on 4.1, rc.d/xendomains has xl.
312: Or fix the package.
313:
314: For 4.2 with xm, add to rc.conf
315:
316: xend=YES
317: xencommons=YES
318:
319: For 4.2 with xl (preferred), add to rc.conf:
320:
321: TODO: explain if there is a xend replacement
322: xencommons=YES
323:
324: TODO: Recommend for/against xen-watchdog.
325:
326: After you have configured the daemons and rebooted, run the following
327: to inspect Xen's boot messages, available resources, and running
328: domains:
329:
330: xm dmesg
331: xm info
332: xm list
333:
334: Updating NetBSD in a dom0
335: -------------------------
336:
337: This is just like updating NetBSD on bare hardware, assuming the new
338: version supports the version of Xen you are running. Generally, one
339: replaces the kernel and reboots, and then overlays userland binaries
340: and adjusts /etc.
341:
342: Note that one must update both the non-Xen kernel typically used for
343: rescue purposes and the DOM0 kernel used with Xen.
344:
345: To convert from grub to /boot, install an mbr bootblock with fdisk,
346: bootxx_ with installboot, /boot and /boot.cfg. This really should be
347: no different than completely reinstalling boot blocks on a non-Xen
348: system.
349:
350: Updating Xen versions
351: ---------------------
352:
353: Updating Xen is conceptually not difficult, but can run into all the
354: issues found when installing Xen. Assuming migration from 4.1 to 4.2,
355: remove the xenkernel41 and xentools41 packages and install the
356: xenkernel42 and xentools42 packages. Copy the 4.2 xen.gz to /.
357:
358: Ensure that the contents of /etc/rc.d/xen* are correct. Enable the
359: correct set of daemons. Ensure that the domU config files are valid
360: for the new version.
361:
362:
363: Unprivileged domains (domU)
364: ===========================
365:
366: This section describes general concepts about domUs. It does not
367: address specific domU operating systems or how to install them. The
368: config files for domUs are typically in /usr/pkg/etc/xen, and are
369: typically named so that the file anme, domU name and the domU's host
370: name match.
371:
372: The domU is provided with cpu and memory by Xen, configured by the
373: dom0. The domU is provided with disk and network by the dom0,
374: mediated by Xen, and configured in the dom0.
375:
376: Entropy in domUs can be an issue; physical disks and network are on
377: the dom0. NetBSD's /dev/random system works, but is often challenged.
378:
379: CPU and memory
380: --------------
381:
382: A domain is provided with some number of vcpus, less than the
383: number of cpus seen by the hypervisor. For a dom0, this is controlled
384: by the boot argument "dom0_max_vcpus=1". For a domU, it is controlled
385: from the config file.
386:
387: A domain is provided with memory, In the straightforward case, the sum
388: of the the memory allocated to the dom0 and all domUs must be less
389: than the available memory.
390:
391: Xen also provides a "balloon" driver, which can be used to let domains
392: use more memory temporarily. TODO: Explain better, and explain how
393: well it works with NetBSD.
394:
395: Virtual disks
396: -------------
397:
398: With the file/vnd style, typically one creates a directory,
399: e.g. /u0/xen, on a disk large enough to hold virtual disks for all
400: domUs. Then, for each domU disk, one writes zeros to a file that then
401: serves to hold the virtual disk's bits; a suggested name is foo-xbd0
402: for the first virtual disk for the domU called foo. Writing zeros to
403: the file serves two purposes. One is that preallocating the contents
404: improves performance. The other is that vnd on sparse files has
405: failed to work. TODO: give working/notworking NetBSD versions for
406: sparse vnd. Note that the use of file/vnd for Xen is not really
407: different than creating a file-backed virtual disk for some other
408: purpose, except that xentools handles the vnconfig commands.
409:
410: With the lvm style, one creates logical devices. They are then used
411: similarly to vnds.
412:
413: Virtual Networking
414: ------------------
415:
416: TODO: explain xvif concept, and that it's general.
417:
418: There are two normal styles: bridging and NAT.
419:
420: With bridging, the domU perceives itself to be on the same network as
421: the dom0. For server virtualization, this is usually best.
422:
423: With NAT, the domU perceives itself to be behind a NAT running on the
424: dom0. This is often appropriate when running Xen on a workstation.
425:
426: One can construct arbitrary other configurations, but there is no
427: script support.
428:
429: Sizing domains
430: --------------
431:
432: Modern x86 hardware has vast amounts of resources. However, many
433: virtual servers can function just fine on far less. A system with
434: 256M of RAM and a 4G disk can be a reasonable choice. Note that it is
435: far easier to adjust virtual resources than physical ones. For
436: memory, it's just a config file edit and a reboot. For disk, one can
437: create a new file and vnconfig it (or lvm), and then dump/restore,
438: just like updating physical disks, but without having to be there and
439: without those pesky connectors.
440:
441: Config files
442: ------------
443:
444: TODO: give example config files. Use both lvm and vnd.
445:
446: TODO: explain the mess with 3 arguments for disks and how to cope (0x1).
447:
448: Starting domains
449: ----------------
450:
451: TODO: Explain "xm start" and "xl start". Explain rc.d/xendomains.
452:
453: TODO: Explain why 4.1 rc.d/xendomains has xl, when one should use xm
454: on 4.1.
455:
456: Creating specific unprivileged domains (domU)
457: =============================================
458:
459: Creating domUs is almost entirely independent of operating system. We
460: first explain NetBSD, and then differences for Linux and Solaris.
461:
462: Creating an unprivileged NetBSD domain (domU)
463: ---------------------------------------------
464:
465: Once you have *domain0* running, you need to start the xen tool daemon
466: (`/usr/pkg/share/examples/rc.d/xend start`) and the xen backend daemon
467: (`/usr/pkg/share/examples/rc.d/xenbackendd start` for Xen3\*,
468: `/usr/pkg/share/examples/rc.d/xencommons start` for Xen4.\*). Make sure
469: that `/dev/xencons` and `/dev/xenevt` exist before starting `xend`. You
470: can create them with this command:
471:
472: # cd /dev && sh MAKEDEV xen
473:
474: xend will write logs to `/var/log/xend.log` and
475: `/var/log/xend-debug.log`. You can then control xen with the xm tool.
476: 'xm list' will show something like:
477:
478: # xm list
479: Name Id Mem(MB) CPU State Time(s) Console
480: Domain-0 0 64 0 r---- 58.1
481:
482: 'xm create' allows you to create a new domain. It uses a config file in
483: PKG\_SYSCONFDIR for its parameters. By default, this file will be in
484: `/usr/pkg/etc/xen/`. On creation, a kernel has to be specified, which
485: will be executed in the new domain (this kernel is in the *domain0* file
486: system, not on the new domain virtual disk; but please note, you should
487: install the same kernel into *domainU* as `/netbsd` in order to make
488: your system tools, like savecore(8), work). A suitable kernel is
489: provided as part of the i386 and amd64 binary sets: XEN3\_DOMU.
490:
491: Here is an /usr/pkg/etc/xen/nbsd example config file:
492:
493: # -*- mode: python; -*-
494: #============================================================================
495: # Python defaults setup for 'xm create'.
496: # Edit this file to reflect the configuration of your system.
497: #============================================================================
498:
499: #----------------------------------------------------------------------------
500: # Kernel image file. This kernel will be loaded in the new domain.
501: kernel = "/home/bouyer/netbsd-XEN3_DOMU"
502: #kernel = "/home/bouyer/netbsd-INSTALL_XEN3_DOMU"
503:
504: # Memory allocation (in megabytes) for the new domain.
505: memory = 128
506:
507: # A handy name for your new domain. This will appear in 'xm list',
508: # and you can use this as parameters for xm in place of the domain
509: # number. All domains must have different names.
510: #
511: name = "nbsd"
512:
513: # The number of virtual CPUs this domain has.
514: #
515: vcpus = 1
516:
517: #----------------------------------------------------------------------------
518: # Define network interfaces for the new domain.
519:
520: # Number of network interfaces (must be at least 1). Default is 1.
521: nics = 1
522:
523: # Define MAC and/or bridge for the network interfaces.
524: #
525: # The MAC address specified in ``mac'' is the one used for the interface
526: # in the new domain. The interface in domain0 will use this address XOR'd
527: # with 00:00:00:01:00:00 (i.e. aa:00:00:51:02:f0 in our example). Random
528: # MACs are assigned if not given.
529: #
530: # ``bridge'' is a required parameter, which will be passed to the
531: # vif-script called by xend(8) when a new domain is created to configure
532: # the new xvif interface in domain0.
533: #
534: # In this example, the xvif is added to bridge0, which should have been
535: # set up prior to the new domain being created -- either in the
536: # ``network'' script or using a /etc/ifconfig.bridge0 file.
537: #
538: vif = [ 'mac=aa:00:00:50:02:f0, bridge=bridge0' ]
539:
540: #----------------------------------------------------------------------------
541: # Define the disk devices you want the domain to have access to, and
542: # what you want them accessible as.
543: #
544: # Each disk entry is of the form:
545: #
546: # phy:DEV,VDEV,MODE
547: #
548: # where DEV is the device, VDEV is the device name the domain will see,
549: # and MODE is r for read-only, w for read-write. You can also create
550: # file-backed domains using disk entries of the form:
551: #
552: # file:PATH,VDEV,MODE
553: #
554: # where PATH is the path to the file used as the virtual disk, and VDEV
555: # and MODE have the same meaning as for ``phy'' devices.
556: #
557: # VDEV doesn't really matter for a NetBSD guest OS (it's just used as an index),
558: # but it does for Linux.
559: # Worse, the device has to exist in /dev/ of domain0, because xm will
560: # try to stat() it. This means that in order to load a Linux guest OS
561: # from a NetBSD domain0, you'll have to create /dev/hda1, /dev/hda2, ...
562: # on domain0, with the major/minor from Linux :(
563: # Alternatively it's possible to specify the device number in hex,
564: # e.g. 0x301 for /dev/hda1, 0x302 for /dev/hda2, etc ...
565:
566: disk = [ 'phy:/dev/wd0e,0x1,w' ]
567: #disk = [ 'file:/var/xen/nbsd-disk,0x01,w' ]
568: #disk = [ 'file:/var/xen/nbsd-disk,0x301,w' ]
569:
570: #----------------------------------------------------------------------------
571: # Set the kernel command line for the new domain.
572:
573: # Set root device. This one does matter for NetBSD
574: root = "xbd0"
575: # extra parameters passed to the kernel
576: # this is where you can set boot flags like -s, -a, etc ...
577: #extra = ""
578:
579: #----------------------------------------------------------------------------
580: # Set according to whether you want the domain restarted when it exits.
581: # The default is False.
582: #autorestart = True
583:
584: # end of nbsd config file ====================================================
585:
586: When a new domain is created, xen calls the
587: `/usr/pkg/etc/xen/vif-bridge` script for each virtual network interface
588: created in *domain0*. This can be used to automatically configure the
589: xvif?.? interfaces in *domain0*. In our example, these will be bridged
590: with the bridge0 device in *domain0*, but the bridge has to exist first.
591: To do this, create the file `/etc/ifconfig.bridge0` and make it look
592: like this:
593:
594: create
595: !brconfig $int add ex0 up
596:
597: (replace `ex0` with the name of your physical interface). Then bridge0
598: will be created on boot. See the bridge(4) man page for details.
599:
600: So, here is a suitable `/usr/pkg/etc/xen/vif-bridge` for xvif?.? (a
601: working vif-bridge is also provided with xentools20) configuring:
602:
603: #!/bin/sh
604: #============================================================================
605: # $NetBSD: howto.mdwn,v 1.36 2014/12/24 16:02:49 gdt Exp $
606: #
607: # /usr/pkg/etc/xen/vif-bridge
608: #
609: # Script for configuring a vif in bridged mode with a dom0 interface.
610: # The xend(8) daemon calls a vif script when bringing a vif up or down.
611: # The script name to use is defined in /usr/pkg/etc/xen/xend-config.sxp
612: # in the ``vif-script'' field.
613: #
614: # Usage: vif-bridge up|down [var=value ...]
615: #
616: # Actions:
617: # up Adds the vif interface to the bridge.
618: # down Removes the vif interface from the bridge.
619: #
620: # Variables:
621: # domain name of the domain the interface is on (required).
622: # vifq vif interface name (required).
623: # mac vif MAC address (required).
624: # bridge bridge to add the vif to (required).
625: #
626: # Example invocation:
627: #
628: # vif-bridge up domain=VM1 vif=xvif1.0 mac="ee:14:01:d0:ec:af" bridge=bridge0
629: #
630: #============================================================================
631:
632: # Exit if anything goes wrong
633: set -e
634:
635: echo "vif-bridge $*"
636:
637: # Operation name.
638: OP=$1; shift
639:
640: # Pull variables in args into environment
641: for arg ; do export "${arg}" ; done
642:
643: # Required parameters. Fail if not set.
644: domain=${domain:?}
645: vif=${vif:?}
646: mac=${mac:?}
647: bridge=${bridge:?}
648:
649: # Optional parameters. Set defaults.
650: ip=${ip:-''} # default to null (do nothing)
651:
652: # Are we going up or down?
653: case $OP in
654: up) brcmd='add' ;;
655: down) brcmd='delete' ;;
656: *)
657: echo 'Invalid command: ' $OP
658: echo 'Valid commands are: up, down'
659: exit 1
660: ;;
661: esac
662:
663: # Don't do anything if the bridge is "null".
664: if [ "${bridge}" = "null" ] ; then
665: exit
666: fi
667:
668: # Don't do anything if the bridge doesn't exist.
669: if ! ifconfig -l | grep "${bridge}" >/dev/null; then
670: exit
671: fi
672:
673: # Add/remove vif to/from bridge.
674: ifconfig x${vif} $OP
675: brconfig ${bridge} ${brcmd} x${vif}
676:
677: Now, running
678:
679: xm create -c /usr/pkg/etc/xen/nbsd
680:
681: should create a domain and load a NetBSD kernel in it. (Note: `-c`
682: causes xm to connect to the domain's console once created.) The kernel
683: will try to find its root file system on xbd0 (i.e., wd0e) which hasn't
684: been created yet. wd0e will be seen as a disk device in the new domain,
685: so it will be 'sub-partitioned'. We could attach a ccd to wd0e in
686: *domain0* and partition it, newfs and extract the NetBSD/i386 or amd64
687: tarballs there, but there's an easier way: load the
688: `netbsd-INSTALL_XEN3_DOMU` kernel provided in the NetBSD binary sets.
689: Like other install kernels, it contains a ramdisk with sysinst, so you
690: can install NetBSD using sysinst on your new domain.
691:
692: If you want to install NetBSD/Xen with a CDROM image, the following line
693: should be used in the `/usr/pkg/etc/xen/nbsd` file:
694:
695: disk = [ 'phy:/dev/wd0e,0x1,w', 'phy:/dev/cd0a,0x2,r' ]
696:
697: After booting the domain, the option to install via CDROM may be
698: selected. The CDROM device should be changed to `xbd1d`.
699:
700: Once done installing, `halt -p` the new domain (don't reboot or halt, it
701: would reload the INSTALL\_XEN3\_DOMU kernel even if you changed the
702: config file), switch the config file back to the XEN3\_DOMU kernel, and
703: start the new domain again. Now it should be able to use `root on xbd0a`
704: and you should have a second, functional NetBSD system on your xen
705: installation.
706:
707: When the new domain is booting you'll see some warnings about *wscons*
708: and the pseudo-terminals. These can be fixed by editing the files
709: `/etc/ttys` and `/etc/wscons.conf`. You must disable all terminals in
710: `/etc/ttys`, except *console*, like this:
711:
712: console "/usr/libexec/getty Pc" vt100 on secure
713: ttyE0 "/usr/libexec/getty Pc" vt220 off secure
714: ttyE1 "/usr/libexec/getty Pc" vt220 off secure
715: ttyE2 "/usr/libexec/getty Pc" vt220 off secure
716: ttyE3 "/usr/libexec/getty Pc" vt220 off secure
717:
718: Finally, all screens must be commented out from `/etc/wscons.conf`.
719:
720: It is also desirable to add
721:
722: powerd=YES
723:
724: in rc.conf. This way, the domain will be properly shut down if
725: `xm shutdown -R` or `xm shutdown -H` is used on the domain0.
726:
727: Your domain should be now ready to work, enjoy.
728:
729: Creating an unprivileged Linux domain (domU)
730: --------------------------------------------
731:
732: Creating unprivileged Linux domains isn't much different from
733: unprivileged NetBSD domains, but there are some details to know.
734:
735: First, the second parameter passed to the disk declaration (the '0x1' in
736: the example below)
737:
738: disk = [ 'phy:/dev/wd0e,0x1,w' ]
739:
740: does matter to Linux. It wants a Linux device number here (e.g. 0x300
741: for hda). Linux builds device numbers as: (major \<\< 8 + minor). So,
742: hda1 which has major 3 and minor 1 on a Linux system will have device
743: number 0x301. Alternatively, devices names can be used (hda, hdb, ...)
744: as xentools has a table to map these names to devices numbers. To export
745: a partition to a Linux guest we can use:
746:
747: disk = [ 'phy:/dev/wd0e,0x300,w' ]
748: root = "/dev/hda1 ro"
749:
750: and it will appear as /dev/hda on the Linux system, and be used as root
751: partition.
752:
753: To install the Linux system on the partition to be exported to the guest
754: domain, the following method can be used: install sysutils/e2fsprogs
755: from pkgsrc. Use mke2fs to format the partition that will be the root
756: partition of your Linux domain, and mount it. Then copy the files from a
757: working Linux system, make adjustments in `/etc` (fstab, network
758: config). It should also be possible to extract binary packages such as
759: .rpm or .deb directly to the mounted partition using the appropriate
760: tool, possibly running under NetBSD's Linux emulation. Once the
761: filesystem has been populated, umount it. If desirable, the filesystem
762: can be converted to ext3 using tune2fs -j. It should now be possible to
763: boot the Linux guest domain, using one of the vmlinuz-\*-xenU kernels
764: available in the Xen binary distribution.
765:
766: To get the linux console right, you need to add:
767:
768: extra = "xencons=tty1"
769:
770: to your configuration since not all linux distributions auto-attach a
771: tty to the xen console.
772:
773: Creating an unprivileged Solaris domain (domU)
774: ----------------------------------------------
775:
776: Download an Opensolaris [release](http://opensolaris.org/os/downloads/)
777: or [development snapshot](http://genunix.org/) DVD image. Attach the DVD
778: image to a MAN.VND.4 device. Copy the kernel and ramdisk filesystem
779: image to your dom0 filesystem.
780:
781: dom0# mkdir /root/solaris
782: dom0# vnconfig vnd0 osol-1002-124-x86.iso
783: dom0# mount /dev/vnd0a /mnt
784:
785: ## for a 64-bit guest
786: dom0# cp /mnt/boot/amd64/x86.microroot /root/solaris
787: dom0# cp /mnt/platform/i86xpv/kernel/amd64/unix /root/solaris
788:
789: ## for a 32-bit guest
790: dom0# cp /mnt/boot/x86.microroot /root/solaris
791: dom0# cp /mnt/platform/i86xpv/kernel/unix /root/solaris
792:
793: dom0# umount /mnt
794:
795:
796: Keep the MAN.VND.4 configured. For some reason the boot process stalls
797: unless the DVD image is attached to the guest as a "phy" device. Create
798: an initial configuration file with the following contents. Substitute
799: */dev/wd0k* with an empty partition at least 8 GB large.
800:
801: memory = 640
802: name = 'solaris'
803: disk = [ 'phy:/dev/wd0k,0,w' ]
804: disk += [ 'phy:/dev/vnd0d,6:cdrom,r' ]
805: vif = [ 'bridge=bridge0' ]
806: kernel = '/root/solaris/unix'
807: ramdisk = '/root/solaris/x86.microroot'
808: # for a 64-bit guest
809: extra = '/platform/i86xpv/kernel/amd64/unix - nowin -B install_media=cdrom'
810: # for a 32-bit guest
811: #extra = '/platform/i86xpv/kernel/unix - nowin -B install_media=cdrom'
812:
813:
814: Start the guest.
815:
816: dom0# xm create -c solaris.cfg
817: Started domain solaris
818: v3.3.2 chgset 'unavailable'
819: SunOS Release 5.11 Version snv_124 64-bit
820: Copyright 1983-2009 Sun Microsystems, Inc. All rights reserved.
821: Use is subject to license terms.
822: Hostname: opensolaris
823: Remounting root read/write
824: Probing for device nodes ...
825: WARNING: emlxs: ddi_modopen drv/fct failed: err 2
826: Preparing live image for use
827: Done mounting Live image
828:
829:
830: Make sure the network is configured. Note that it can take a minute for
831: the xnf0 interface to appear.
832:
833: opensolaris console login: jack
834: Password: jack
835: Sun Microsystems Inc. SunOS 5.11 snv_124 November 2008
836: jack@opensolaris:~$ pfexec sh
837: sh-3.2# ifconfig -a
838: sh-3.2# exit
839:
840:
841: Set a password for VNC and start the VNC server which provides the X11
842: display where the installation program runs.
843:
844: jack@opensolaris:~$ vncpasswd
845: Password: solaris
846: Verify: solaris
847: jack@opensolaris:~$ cp .Xclients .vnc/xstartup
848: jack@opensolaris:~$ vncserver :1
849:
850:
851: From a remote machine connect to the VNC server. Use `ifconfig xnf0` on
852: the guest to find the correct IP address to use.
853:
854: remote$ vncviewer 172.18.2.99:1
855:
856:
857: It is also possible to launch the installation on a remote X11 display.
858:
859: jack@opensolaris:~$ export DISPLAY=172.18.1.1:0
860: jack@opensolaris:~$ pfexec gui-install
861:
862:
863: After the GUI installation is complete you will be asked to reboot.
864: Before that you need to determine the ZFS ID for the new boot filesystem
865: and update the configuration file accordingly. Return to the guest
866: console.
867:
868: jack@opensolaris:~$ pfexec zdb -vvv rpool | grep bootfs
869: bootfs = 43
870: ^C
871: jack@opensolaris:~$
872:
873:
874: The final configuration file should look like this. Note in particular
875: the last line.
876:
877: memory = 640
878: name = 'solaris'
879: disk = [ 'phy:/dev/wd0k,0,w' ]
880: vif = [ 'bridge=bridge0' ]
881: kernel = '/root/solaris/unix'
882: ramdisk = '/root/solaris/x86.microroot'
883: extra = '/platform/i86xpv/kernel/amd64/unix -B zfs-bootfs=rpool/43,bootpath="/xpvd/xdf@0:a"'
884:
885:
886: Restart the guest to verify it works correctly.
887:
888: dom0# xm destroy solaris
889: dom0# xm create -c solaris.cfg
890: Using config file "./solaris.cfg".
891: v3.3.2 chgset 'unavailable'
892: Started domain solaris
893: SunOS Release 5.11 Version snv_124 64-bit
894: Copyright 1983-2009 Sun Microsystems, Inc. All rights reserved.
895: Use is subject to license terms.
896: WARNING: emlxs: ddi_modopen drv/fct failed: err 2
897: Hostname: osol
898: Configuring devices.
899: Loading smf(5) service descriptions: 160/160
900: svccfg import warnings. See /var/svc/log/system-manifest-import:default.log .
901: Reading ZFS config: done.
902: Mounting ZFS filesystems: (6/6)
903: Creating new rsa public/private host key pair
904: Creating new dsa public/private host key pair
905:
906: osol console login:
907:
908:
909: Using PCI devices in guest domains
910: ----------------------------------
911:
912: The domain0 can give other domains access to selected PCI devices. This
913: can allow, for example, a non-privileged domain to have access to a
914: physical network interface or disk controller. However, keep in mind
915: that giving a domain access to a PCI device most likely will give the
916: domain read/write access to the whole physical memory, as PCs don't have
917: an IOMMU to restrict memory access to DMA-capable device. Also, it's not
918: possible to export ISA devices to non-domain0 domains (which means that
919: the primary VGA adapter can't be exported. A guest domain trying to
920: access the VGA registers will panic).
921:
922: This functionality is only available in NetBSD-5.1 (and later) domain0
923: and domU. If the domain0 is NetBSD, it has to be running Xen 3.1, as
924: support has not been ported to later versions at this time.
925:
926: For a PCI device to be exported to a domU, is has to be attached to the
927: `pciback` driver in domain0. Devices passed to the domain0 via the
928: pciback.hide boot parameter will attach to `pciback` instead of the
929: usual driver. The list of devices is specified as `(bus:dev.func)`,
930: where bus and dev are 2-digit hexadecimal numbers, and func a
931: single-digit number:
932:
933: pciback.hide=(00:0a.0)(00:06.0)
934:
935: pciback devices should show up in the domain0's boot messages, and the
936: devices should be listed in the `/kern/xen/pci` directory.
937:
938: PCI devices to be exported to a domU are listed in the `pci` array of
939: the domU's config file, with the format `'0000:bus:dev.func'`
940:
941: pci = [ '0000:00:06.0', '0000:00:0a.0' ]
942:
943: In the domU an `xpci` device will show up, to which one or more pci
944: busses will attach. Then the PCI drivers will attach to PCI busses as
945: usual. Note that the default NetBSD DOMU kernels do not have `xpci` or
946: any PCI drivers built in by default; you have to build your own kernel
947: to use PCI devices in a domU. Here's a kernel config example:
948:
949: include "arch/i386/conf/XEN3_DOMU"
950: #include "arch/i386/conf/XENU" # in NetBSD 3.0
951:
952: # Add support for PCI busses to the XEN3_DOMU kernel
953: xpci* at xenbus ?
954: pci* at xpci ?
955:
956: # Now add PCI and related devices to be used by this domain
957: # USB Controller and Devices
958:
959: # PCI USB controllers
960: uhci* at pci? dev ? function ? # Universal Host Controller (Intel)
961:
962: # USB bus support
963: usb* at uhci?
964:
965: # USB Hubs
966: uhub* at usb?
967: uhub* at uhub? port ? configuration ? interface ?
968:
969: # USB Mass Storage
970: umass* at uhub? port ? configuration ? interface ?
971: wd* at umass?
972: # SCSI controllers
973: ahc* at pci? dev ? function ? # Adaptec [23]94x, aic78x0 SCSI
974:
975: # SCSI bus support (for both ahc and umass)
976: scsibus* at scsi?
977:
978: # SCSI devices
979: sd* at scsibus? target ? lun ? # SCSI disk drives
980: cd* at scsibus? target ? lun ? # SCSI CD-ROM drives
981:
982:
983: NetBSD as a domU in a VPS
984: =========================
985:
986: The bulk of the HOWTO is about using NetBSD as a dom0 on your own
987: hardware. This section explains how to deal with Xen in a domU as a
988: virtual private server where you do not control or have access to the
989: dom0.
990:
991: TODO: Perhaps reference panix, prmgr, amazon as interesting examples.
992:
993: TODO: Somewhere, discuss pvgrub and py-grub to load the domU kernel
994: from the domU filesystem.
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