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Annotation of wikisrc/ports/xen/howto.mdwn, revision 1.132

1.5 mspo 1: Introduction
1.13 gdt 2: ============
1.1 mspo 3:
4: [![[Xen
1.57 gdt 5: screenshot]](http://www.netbsd.org/gallery/in-Action/hubertf-xens.png)](http://www.netbsd.org/gallery/in-Action/hubertf-xen.png)
1.1 mspo 6:
1.58 gdt 7: Xen is a hypervisor (or virtual machine monitor) for x86 hardware
1.12 gdt 8: (i686-class or higher), which supports running multiple guest
1.58 gdt 9: operating systems on a single physical machine. Xen is a Type 1 or
10: bare-metal hypervisor; one uses the Xen kernel to control the CPU,
11: memory and console, a dom0 operating system which mediates access to
12: other hardware (e.g., disks, network, USB), and one or more domU
13: operating systems which operate in an unprivileged virtualized
14: environment. IO requests from the domU systems are forwarded by the
15: hypervisor (Xen) to the dom0 to be fulfilled.
1.12 gdt 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:
1.123 gdt 30: Generally any machine that runs NetBSD/amd64 will work with Xen and PV
31: guests. In theory i386 computers (without x86_64/amd64 support) can
32: be used for Xen <= 4.2, but we have no recent reports of this working
33: (this is a hint). For HVM guests, hardware support is needed, but it
34: is common on recent machines. For Intel CPUs, one needs the VT-x
35: extension, shown in "cpuctl identify 0" as VMX. For AMD CPUs, one
36: needs the AMD-V extensions, shown in "cpuctl identify 0" as SVM.
37: There are further features for IOMMU virtualization, Intel's VT-d and
38: AMD's AMD-Vi. TODO: Explain whether Xen on NetBSD makes use of these
39: features. TODO: Review by someone who really understands this.
1.19 gdt 40:
1.123 gdt 41: Note that a FreeBSD dom0 requires VT-x and VT-d (or equivalent); this
42: is because the FreeBSD dom0 does not run in PV mode.
1.118 gdt 43:
1.27 jnemeth 44: At boot, the dom0 kernel is loaded as a module with Xen as the kernel.
1.12 gdt 45: The dom0 can start one or more domUs. (Booting is explained in detail
46: in the dom0 section.)
47:
48: NetBSD supports Xen in that it can serve as dom0, be used as a domU,
49: and that Xen kernels and tools are available in pkgsrc. This HOWTO
50: attempts to address both the case of running a NetBSD dom0 on hardware
1.24 gdt 51: and running domUs under it (NetBSD and other), and also running NetBSD
52: as a domU in a VPS.
1.12 gdt 53:
1.123 gdt 54: Xen 3.1 in pkgsrc supports "PCI passthrough", which means that
1.20 gdt 55: specific PCI devices can be made available to a specific domU instead
56: of the dom0. This can be useful to let a domU run X11, or access some
57: network interface or other peripheral.
58:
1.111 wiz 59: NetBSD 6 and earlier supported Xen 2; support was removed from NetBSD
1.104 gdt 60: 7. Xen 2 has been removed from pkgsrc.
1.54 gdt 61:
1.12 gdt 62: Prerequisites
1.13 gdt 63: -------------
1.12 gdt 64:
65: Installing NetBSD/Xen is not extremely difficult, but it is more
66: complex than a normal installation of NetBSD.
1.15 gdt 67: In general, this HOWTO is occasionally overly restrictive about how
68: things must be done, guiding the reader to stay on the established
69: path when there are no known good reasons to stray.
1.12 gdt 70:
71: This HOWTO presumes a basic familiarity with the Xen system
1.123 gdt 72: architecture, with installing NetBSD on i386/amd64 hardware, and with
73: installing software from pkgsrc. See also the [Xen
74: website](http://www.xenproject.org/).
1.1 mspo 75:
1.15 gdt 76: Versions of Xen and NetBSD
77: ==========================
78:
1.27 jnemeth 79: Most of the installation concepts and instructions are independent
80: of Xen version and NetBSD version. This section gives advice on
81: which version to choose. Versions not in pkgsrc and older unsupported
82: versions of NetBSD are intentionally ignored.
1.15 gdt 83:
84: Xen
85: ---
86:
1.111 wiz 87: In NetBSD, Xen is provided in pkgsrc, via matching pairs of packages
1.15 gdt 88: xenkernel and xentools. We will refer only to the kernel versions,
89: but note that both packages must be installed together and must have
90: matching versions.
91:
1.104 gdt 92: xenkernel3 provides Xen 3.1. It is no longer maintained by Xen, and the last applied security patch was in
93: 2011. Thus, it should not be used. It supports PCI passthrough,
94: which is why people use it anyway. Xen 3.1 supports i386, both PAE and
95: non-PAE.
96:
97: xenkernel33 provides Xen 3.3. It is no longer maintained by Xen, and
98: the last applied security patch was in 2012. Thus, it should not be
99: used. Xen 3.3 supports i386, but only in PAE mode. There are no good
100: reasons to run this version.
101:
102: xenkernel41 provides Xen 4.1. It is no longer maintained by Xen, but
1.112 gdt 103: as of 2016-12 received backported security patches. Xen 4.1 supports
1.104 gdt 104: i386, but only in PAE mode. There are no good reasons to run this
105: version.
1.102 gdt 106:
1.104 gdt 107: xenkernel42 provides Xen 4.2. It is no longer maintained by Xen, but
1.112 gdt 108: as of 2016-12 received backported security patches. Xen 4.2 supports
1.104 gdt 109: i386, but only in PAE mode. The only reason to run this is if you
110: need to use xm instead of xl, or if you need to run an i386 dom0
111: (because your hardware is i386 only).
112:
1.114 gdt 113: xenkernel45 provides Xen 4.5. As of 2016-12, security patches were
1.119 gdt 114: released by Xen and applied to pkgsrc. Xen 4.5 requires using a dom0
115: running NetBSD's amd64 port (Intel or AMD hardware is fine), but domUs
1.131 gdt 116: can be amd64 or i386 PAE. While slightly old, n4.5 has been tested and
117: run by others, so it is the conservative choice.
1.104 gdt 118:
1.115 gdt 119: xenkernel46 provides Xen 4.6. It is new to pkgsrc as of 2016-05. As
1.114 gdt 120: of 2016-12, security patches were released by Xen and applied to
1.119 gdt 121: pkgsrc. Xen 4.6 similarly requires a NetBSD/amd64 dom0, but domUs can
1.131 gdt 122: be amd64 or i386 PAE. For new installations, 4.6 is probably the
123: appropriate choice and it will likely soon be the standard approach.
1.85 gdt 124:
1.114 gdt 125: Xen 4.7 (released 2016-06) and 4.8 (released 2016-12) are not yet in
126: pkgsrc.
1.113 gdt 127:
1.96 gdt 128: See also the [Xen Security Advisory page](http://xenbits.xen.org/xsa/).
129:
1.85 gdt 130: Note that NetBSD support is called XEN3. It works with Xen 3 and Xen
131: 4 because the hypercall interface has been stable.
1.20 gdt 132:
1.19 gdt 133: Xen command program
134: -------------------
135:
1.79 gdt 136: Early Xen used a program called xm to manipulate the system from the
1.19 gdt 137: dom0. Starting in 4.1, a replacement program with similar behavior
1.79 gdt 138: called xl is provided, but it does not work well in 4.1. In 4.2, both
1.127 gdt 139: xm and xl work fine. 4.4 is the last version that has xm.
140:
141: You must make a global choice to use xm or xl, because it affects not
142: only which command you use, but the command used by rc.d scripts
143: (specifically xendomains) and which daemons should be run. The
144: xentools packages provide xm for 3.1, 3.3 and 4.1 and xl for 4.2 and up.
145:
146: In 4.2, you can choose to use xm by simply changing the ctl_command
147: variable.
148:
149: With xl, virtual devices are configured in parallel, which can cause
150: problems if they are written assuming serial operation (e.g., updating
1.130 gdt 151: firewall rules without explicit locking). There is now locking for
152: the provided scripts, which works for normal casses (e.g, file-backed
153: xbd, where a vnd must be allocated). But, as of 201612, it has not
154: been adequately tested for a complex custom setup with a large number
155: of interfaces.
1.19 gdt 156:
1.15 gdt 157: NetBSD
158: ------
159:
1.105 gdt 160: The netbsd-6, netbsd-7, and -current branches are all reasonable
161: choices, with more or less the same considerations for non-Xen use.
162: Therefore, netbsd-7 is recommended as the stable version of the most
1.117 gdt 163: recent release for production use. In addition, netbsd-7 and -current
164: have a important scheduler fix (in November of 2015) affecting
165: contention between dom0 and domUs; see
166: https://releng.netbsd.org/cgi-bin/req-7.cgi?show=1040 for a
167: description. For those wanting to learn Xen or without production
168: stability concerns, netbsd-7 is still likely most appropriate, but
169: -current is also a reasonable choice. (Xen runs ok on netbsd-5, but
170: the xentools packages are likely difficult to build, and netbsd-5 is
171: not supported.)
1.15 gdt 172:
173: As of NetBSD 6, a NetBSD domU will support multiple vcpus. There is
174: no SMP support for NetBSD as dom0. (The dom0 itself doesn't really
1.105 gdt 175: need SMP for dom0 functions; the lack of support is really a problem
176: when using a dom0 as a normal computer.)
1.15 gdt 177:
1.18 gdt 178: Architecture
179: ------------
180:
1.108 gdt 181: Xen itself can run on i386 (Xen < 3.1) or amd64 machines (all Xen
1.105 gdt 182: versions). (Practically, almost any computer where one would want to
183: run Xen today supports amd64.)
1.99 gdt 184:
185: Xen, the dom0 kernel, and each domU kernel can be either i386 or
186: amd64. When building a xenkernel package, one obtains i386 on an i386
1.111 wiz 187: host, and amd64 on an amd64 host. If the Xen kernel is i386, then the
188: dom0 kernel and all domU kernels must be i386. With an amd64 Xen
1.105 gdt 189: kernel, an amd64 dom0 kernel is known to work, and an i386PAE dom0
1.111 wiz 190: kernel should in theory work. An amd64 Xen/dom0 is known to support
1.105 gdt 191: both i386PAE and amd64 domUs.
1.99 gdt 192:
1.101 gdt 193: i386 dom0 and domU kernels must be PAE (except for Xen 3.1); these are
194: built by default. (Note that emacs (at least) fails if run on i386
195: with PAE when built without, and vice versa, presumably due to bugs in
196: the undump code.)
1.99 gdt 197:
198: Because of the above, the standard approach is to use amd64 for the
199: dom0.
1.29 gdt 200:
201: Xen 4.2 is the last version to support i386 as a host. TODO: Clarify
1.111 wiz 202: if this is about the CPU, the Xen kernel, or the dom0 kernel having to
1.100 gdt 203: be amd64.
204:
1.29 gdt 205:
1.89 gdt 206: Stability
207: ---------
208:
209: Mostly, NetBSD as a dom0 or domU is quite stable.
210: However, there are some open PRs indicating problems.
211:
1.91 gdt 212: - [PR 48125](http://gnats.netbsd.org/48125)
213: - [PR 47720](http://gnats.netbsd.org/47720)
1.89 gdt 214:
215: Note also that there are issues with sparse vnd(4) instances, but
1.105 gdt 216: these are not about Xen -- they just are noticed with sparse vnd(4)
217: instances in support of virtual disks in a dom0.
1.89 gdt 218:
1.15 gdt 219: Recommendation
220: --------------
221:
1.105 gdt 222: Therefore, this HOWTO recommends running xenkernel45 or xenkernel46,
223: xl, the NetBSD 7 stable branch, and to use an amd64 kernel as the
224: dom0. Either the i386PAE or amd64 version of NetBSD may be used as
225: domUs.
1.15 gdt 226:
1.125 gdt 227: Status
228: ------
1.36 gdt 229:
1.120 gdt 230: Ideally, all versions of Xen in pkgsrc would build on all supported
1.121 gdt 231: versions of NetBSD/amd64, to the point where this section would be
232: silly. However, that has not always been the case. Besides aging
233: code and aging compilers, qemu (included in xentools for HVM support)
1.124 gdt 234: is difficult to build. Note that there is intentionally no data for
1.125 gdt 235: 4.5+ up for i386, and often omits xentools info if the corresponding
236: kernel fails.
237:
238: The following table gives status, with the date last checked
239: (generally on the most recent quarterly branch). The first code is
240: "builds" if it builds ok, and "FAIL" for a failure to build. The
241: second code/date only appears for xenkernel* and is "works" if it runs
242: ok as a dom0, and "FAIL" if it won't boot or run a domU.
1.124 gdt 243:
244: xenkernel3 netbsd-6 i386 FAIL 201612
245: xenkernel33 netbsd-6 i386 FAIL 201612
1.125 gdt 246: xenkernel41 netbsd-6 i386 builds 201612
247: xenkernel42 netbsd-6 i386 builds 201612
1.126 gdt 248: xentools3 netbsd-6 i386 FAIL 201612
1.128 gdt 249: xentools33 netbsd-6 i386 FAIL 201612
1.125 gdt 250: xentools41 netbsd-6 i386 builds 201612
1.126 gdt 251: xentools42 netbsd-6 i386 FAIL 201612
1.64 gdt 252:
1.124 gdt 253: xenkernel3 netbsd-7 i386 FAIL 201412
254: xenkernel33 netbsd-7 i386 FAIL 201412
1.125 gdt 255: xenkernel41 netbsd-7 i386 builds 201412
256: xenkernel42 netbsd-7 i386 builds 201412
257: xentools41 netbsd-7 i386 builds 201412
1.122 gdt 258: xentools42 netbsd-7 i386 ??FAIL 201412
1.121 gdt 259:
1.124 gdt 260: xenkernel3 netbsd-6 amd64 FAIL 201612
261: xenkernel33 netbsd-6 amd64 FAIL 201612
1.125 gdt 262: xenkernel41 netbsd-6 amd64 builds 201612 works 201612
1.126 gdt 263: xenkernel42 netbsd-6 amd64 builds 201612 works 201612
1.125 gdt 264: xenkernel45 netbsd-6 amd64 builds 201612
265: xenkernel46 netbsd-6 amd64 builds 201612
266: xentools41 netbsd-6 amd64 builds 201612
267: xentools42 netbsd-6 amd64 builds 201612
268: xentools45 netbsd-6 amd64 builds 201612
1.124 gdt 269: xentools46 netbsd-6 amd64 FAIL 201612
1.121 gdt 270:
1.125 gdt 271: xenkernel3 netbsd-7 amd64 builds 201612
272: xenkernel33 netbsd-7 amd64 builds 201612
273: xenkernel41 netbsd-7 amd64 builds 201612
274: xenkernel42 netbsd-7 amd64 builds 201612
275: xenkernel45 netbsd-7 amd64 builds 201612
276: xenkernel46 netbsd-7 amd64 builds 201612
277: xentools3 netbsd-7 amd64 builds 201612
278: xentools3-hvm netbsd-7 amd64 builds 201612
1.121 gdt 279: xentools33 netbsd-7 amd64 FAIL 201612
1.125 gdt 280: xentools41 netbsd-7 amd64 builds 201612
281: xentools42 netbsd-7 amd64 builds 201612
282: xentools45 netbsd-7 amd64 builds 201612
283: xentools46 netbsd-7 amd64 builds 201612
1.69 gdt 284:
1.15 gdt 285: NetBSD as a dom0
286: ================
287:
288: NetBSD can be used as a dom0 and works very well. The following
289: sections address installation, updating NetBSD, and updating Xen.
1.19 gdt 290: Note that it doesn't make sense to talk about installing a dom0 OS
291: without also installing Xen itself. We first address installing
292: NetBSD, which is not yet a dom0, and then adding Xen, pivoting the
293: NetBSD install to a dom0 install by just changing the kernel and boot
294: configuration.
1.15 gdt 295:
1.45 gdt 296: For experimenting with Xen, a machine with as little as 1G of RAM and
297: 100G of disk can work. For running many domUs in productions, far
298: more will be needed.
299:
1.15 gdt 300: Styles of dom0 operation
301: ------------------------
302:
303: There are two basic ways to use Xen. The traditional method is for
304: the dom0 to do absolutely nothing other than providing support to some
305: number of domUs. Such a system was probably installed for the sole
306: purpose of hosting domUs, and sits in a server room on a UPS.
307:
308: The other way is to put Xen under a normal-usage computer, so that the
309: dom0 is what the computer would have been without Xen, perhaps a
310: desktop or laptop. Then, one can run domUs at will. Purists will
311: deride this as less secure than the previous approach, and for a
312: computer whose purpose is to run domUs, they are right. But Xen and a
1.93 gdt 313: dom0 (without domUs) is not meaningfully less secure than the same
1.15 gdt 314: things running without Xen. One can boot Xen or boot regular NetBSD
315: alternately with little problems, simply refraining from starting the
316: Xen daemons when not running Xen.
317:
318: Note that NetBSD as dom0 does not support multiple CPUs. This will
1.51 gdt 319: limit the performance of the Xen/dom0 workstation approach. In theory
320: the only issue is that the "backend drivers" are not yet MPSAFE:
321: http://mail-index.netbsd.org/netbsd-users/2014/08/29/msg015195.html
1.15 gdt 322:
1.19 gdt 323: Installation of NetBSD
324: ----------------------
1.13 gdt 325:
1.19 gdt 326: First,
1.27 jnemeth 327: [install NetBSD/amd64](/guide/inst/)
1.19 gdt 328: just as you would if you were not using Xen.
329: However, the partitioning approach is very important.
330:
331: If you want to use RAIDframe for the dom0, there are no special issues
332: for Xen. Typically one provides RAID storage for the dom0, and the
1.22 gdt 333: domU systems are unaware of RAID. The 2nd-stage loader bootxx_* skips
1.111 wiz 334: over a RAID1 header to find /boot from a file system within a RAID
1.22 gdt 335: partition; this is no different when booting Xen.
1.19 gdt 336:
337: There are 4 styles of providing backing storage for the virtual disks
1.93 gdt 338: used by domUs: raw partitions, LVM, file-backed vnd(4), and SAN.
1.19 gdt 339:
340: With raw partitions, one has a disklabel (or gpt) partition sized for
341: each virtual disk to be used by the domU. (If you are able to predict
342: how domU usage will evolve, please add an explanation to the HOWTO.
343: Seriously, needs tend to change over time.)
344:
1.27 jnemeth 345: One can use [lvm(8)](/guide/lvm/) to create logical devices to use
346: for domU disks. This is almost as efficient as raw disk partitions
347: and more flexible. Hence raw disk partitions should typically not
348: be used.
1.19 gdt 349:
1.111 wiz 350: One can use files in the dom0 file system, typically created by dd'ing
1.19 gdt 351: /dev/zero to create a specific size. This is somewhat less efficient,
352: but very convenient, as one can cp the files for backup, or move them
353: between dom0 hosts.
354:
355: Finally, in theory one can place the files backing the domU disks in a
356: SAN. (This is an invitation for someone who has done this to add a
357: HOWTO page.)
1.1 mspo 358:
1.19 gdt 359: Installation of Xen
360: -------------------
1.1 mspo 361:
1.20 gdt 362: In the dom0, install sysutils/xenkernel42 and sysutils/xentools42 from
1.127 gdt 363: pkgsrc (or another matching pair). See [the pkgsrc
364: documentation](http://www.NetBSD.org/docs/pkgsrc/) for help with
365: pkgsrc. Ensure that your packages are recent; the HOWTO does not
366: contemplate old builds.
367:
1.20 gdt 368:
369: For Xen 3.1, support for HVM guests is in sysutils/xentool3-hvm. More
370: recent versions have HVM support integrated in the main xentools
371: package. It is entirely reasonable to run only PV guests.
372:
373: Next you need to install the selected Xen kernel itself, which is
374: installed by pkgsrc as "/usr/pkg/xen*-kernel/xen.gz". Copy it to /.
375: For debugging, one may copy xen-debug.gz; this is conceptually similar
376: to DIAGNOSTIC and DEBUG in NetBSD. xen-debug.gz is basically only
377: useful with a serial console. Then, place a NetBSD XEN3_DOM0 kernel
378: in /, copied from releasedir/amd64/binary/kernel/netbsd-XEN3_DOM0.gz
1.75 gdt 379: of a NetBSD build. If using i386, use
380: releasedir/i386/binary/kernel/netbsd-XEN3PAE_DOM0.gz. (If using Xen
381: 3.1 and i386, you may use XEN3_DOM0 with the non-PAE Xen. But you
382: should not use Xen 3.1.) Both xen and the NetBSD kernel may be (and
383: typically are) left compressed.
384:
1.111 wiz 385: In a dom0 kernel, kernfs is mandatory for xend to communicate with the
1.75 gdt 386: kernel, so ensure that /kern is in fstab. TODO: Say this is default,
387: or file a PR and give a reference.
1.20 gdt 388:
389: Because you already installed NetBSD, you have a working boot setup
390: with an MBR bootblock, either bootxx_ffsv1 or bootxx_ffsv2 at the
1.111 wiz 391: beginning of your root file system, /boot present, and likely
1.20 gdt 392: /boot.cfg. (If not, fix before continuing!)
393:
1.76 gdt 394: Add a line to to /boot.cfg to boot Xen. See boot.cfg(5) for an
395: example. The basic line is
1.20 gdt 396:
1.37 gdt 397: menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=256M
1.20 gdt 398:
399: which specifies that the dom0 should have 256M, leaving the rest to be
1.77 gdt 400: allocated for domUs. To use a serial console, use
401:
402: menu=Xen:load /netbsd-XEN3_DOM0.gz console=com0;multiboot /xen.gz dom0_mem=256M console=com1 com1=9600,8n1
403:
404: which will use the first serial port for Xen (which counts starting
405: from 1), forcing speed/parity, and also for NetBSD (which counts
406: starting at 0). In an attempt to add performance, one can also add
1.37 gdt 407:
408: dom0_max_vcpus=1 dom0_vcpus_pin
409:
410: to force only one vcpu to be provided (since NetBSD dom0 can't use
1.111 wiz 411: more) and to pin that vcpu to a physical CPU. TODO: benchmark this.
1.20 gdt 412:
1.93 gdt 413: Xen has [many boot
414: options](http://xenbits.xenproject.org/docs/4.5-testing/misc/xen-command-line.html),
1.111 wiz 415: and other than dom0 memory and max_vcpus, they are generally not
1.93 gdt 416: necessary.
417:
1.20 gdt 418: As with non-Xen systems, you should have a line to boot /netbsd (a
1.127 gdt 419: kernel that works without Xen). Consider a line to boot /netbsd.ok (a
420: fallback version of the non-Xen kernel, updated manually when you are
421: sure /netbsd is ok). Consider also a line to boot fallback versions
422: of Xen and the dom0 kernel, but note that non-Xen NetBSD can be used
423: to resolve Xen booting issues.
424:
425: Probably you want a default=N line to choose Xen in the absence of
426: intervention.
1.1 mspo 427:
1.76 gdt 428: Now, reboot so that you are running a DOM0 kernel under Xen, rather
429: than GENERIC without Xen.
430:
1.54 gdt 431: Using grub (historic)
432: ---------------------
433:
434: Before NetBSD's native bootloader could support Xen, the use of
435: grub was recommended. If necessary, see the
436: [old grub information](/ports/xen/howto-grub/).
437:
1.28 gdt 438: The [HowTo on Installing into
439: RAID-1](http://mail-index.NetBSD.org/port-xen/2006/03/01/0010.html)
440: explains how to set up booting a dom0 with Xen using grub with
441: NetBSD's RAIDframe. (This is obsolete with the use of NetBSD's native
442: boot.)
443:
1.21 gdt 444: Configuring Xen
445: ---------------
446:
1.53 gdt 447: Xen logs will be in /var/log/xen.
448:
1.76 gdt 449: Now, you have a system that will boot Xen and the dom0 kernel, but not
450: do anything else special. Make sure that you have rebooted into Xen.
451: There will be no domUs, and none can be started because you still have
1.102 gdt 452: to configure the dom0 daemons.
1.21 gdt 453:
1.102 gdt 454: The daemons which should be run vary with Xen version and with whether
1.127 gdt 455: one is using xm or xl. The Xen 3.1, 3.3 and 4.1 packages use xm. Xen
456: 4.2 and up packages use xl. To use xm with 4.2, edit xendomains to
457: use xm instead.
458:
1.132 ! gdt 459: For 3.1 and 3.3, you should enable xend and xenbackendd:
1.31 gdt 460:
1.32 gdt 461: xend=YES
462: xenbackendd=YES
1.31 gdt 463:
1.132 ! gdt 464: For 4.1 and up, you should enable xencommons. Not enabling xencommons
! 465: will result in a hang; it is necessary to hit ^C on the console to let
! 466: the machine finish booting. If you are using xm (default in 4.1, or
! 467: if you changed xendomains in 4.2), you should also enable xend:
1.31 gdt 468:
1.132 ! gdt 469: xend=YES # only if using xm, and only installed <= 4.2
1.53 gdt 470: xencommons=YES
1.31 gdt 471:
472: TODO: Recommend for/against xen-watchdog.
1.27 jnemeth 473:
1.53 gdt 474: After you have configured the daemons and either started them (in the
1.79 gdt 475: order given) or rebooted, use xm or xl to inspect Xen's boot messages,
1.102 gdt 476: available resources, and running domains. An example with xl follows:
1.34 gdt 477:
1.102 gdt 478: # xl dmesg
1.43 gdt 479: [xen's boot info]
1.102 gdt 480: # xl info
1.43 gdt 481: [available memory, etc.]
1.102 gdt 482: # xl list
1.43 gdt 483: Name Id Mem(MB) CPU State Time(s) Console
484: Domain-0 0 64 0 r---- 58.1
1.33 gdt 485:
1.88 gdt 486: ### Issues with xencommons
487:
488: xencommons starts xenstored, which stores data on behalf of dom0 and
489: domUs. It does not currently work to stop and start xenstored.
490: Certainly all domUs should be shutdown first, following the sort order
491: of the rc.d scripts. However, the dom0 sets up state with xenstored,
492: and is not notified when xenstored exits, leading to not recreating
493: the state when the new xenstored starts. Until there's a mechanism to
494: make this work, one should not expect to be able to restart xenstored
495: (and thus xencommons). There is currently no reason to expect that
496: this will get fixed any time soon.
497:
1.127 gdt 498: ### No-longer needed advice about devices
499:
500: The installation of NetBSD should already have created devices for xen
501: (xencons, xenevt, xsd_kva), but if they are not present, create them:
502:
503: cd /dev && sh MAKEDEV xen
504:
1.41 gdt 505: anita (for testing NetBSD)
506: --------------------------
507:
1.82 gdt 508: With the setup so far (assuming 4.2/xl), one should be able to run
509: anita (see pkgsrc/misc/py-anita) to test NetBSD releases, by doing (as
510: root, because anita must create a domU):
511:
512: anita --vmm=xl test file:///usr/obj/i386/
513:
514: Alternatively, one can use --vmm=xm to use xm-based domU creation
515: instead (and must, on Xen <= 4.1). TODO: confirm that anita xl really works.
516:
1.40 gdt 517: Xen-specific NetBSD issues
518: --------------------------
519:
520: There are (at least) two additional things different about NetBSD as a
521: dom0 kernel compared to hardware.
522:
1.111 wiz 523: One is that the module ABI is different because some of the #defines
1.109 gdt 524: change, so one must build modules for Xen. As of netbsd-7, the build
525: system does this automatically. TODO: check this. (Before building
526: Xen modules was added, it was awkward to use modules to the point
527: where it was considered that it did not work.)
1.40 gdt 528:
529: The other difference is that XEN3_DOM0 does not have exactly the same
530: options as GENERIC. While it is debatable whether or not this is a
531: bug, users should be aware of this and can simply add missing config
532: items if desired.
533:
1.15 gdt 534: Updating NetBSD in a dom0
535: -------------------------
536:
537: This is just like updating NetBSD on bare hardware, assuming the new
538: version supports the version of Xen you are running. Generally, one
539: replaces the kernel and reboots, and then overlays userland binaries
540: and adjusts /etc.
541:
542: Note that one must update both the non-Xen kernel typically used for
543: rescue purposes and the DOM0 kernel used with Xen.
544:
1.55 gdt 545: Converting from grub to /boot
546: -----------------------------
547:
548: These instructions were [TODO: will be] used to convert a system from
549: grub to /boot. The system was originally installed in February of
550: 2006 with a RAID1 setup and grub to boot Xen 2, and has been updated
551: over time. Before these commands, it was running NetBSD 6 i386, Xen
552: 4.1 and grub, much like the message linked earlier in the grub
553: section.
554:
1.111 wiz 555: # Install MBR bootblocks on both disks.
1.55 gdt 556: fdisk -i /dev/rwd0d
557: fdisk -i /dev/rwd1d
558: # Install NetBSD primary boot loader (/ is FFSv1) into RAID1 components.
559: installboot -v /dev/rwd0d /usr/mdec/bootxx_ffsv1
560: installboot -v /dev/rwd1d /usr/mdec/bootxx_ffsv1
561: # Install secondary boot loader
562: cp -p /usr/mdec/boot /
1.111 wiz 563: # Create boot.cfg following earlier guidance:
1.55 gdt 564: menu=Xen:load /netbsd-XEN3PAE_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=256M
565: menu=Xen.ok:load /netbsd-XEN3PAE_DOM0.ok.gz console=pc;multiboot /xen.ok.gz dom0_mem=256M
566: menu=GENERIC:boot
567: menu=GENERIC single-user:boot -s
568: menu=GENERIC.ok:boot netbsd.ok
569: menu=GENERIC.ok single-user:boot netbsd.ok -s
570: menu=Drop to boot prompt:prompt
571: default=1
572: timeout=30
573:
574: TODO: actually do this and fix it if necessary.
1.22 gdt 575:
1.102 gdt 576: Upgrading Xen versions
1.15 gdt 577: ---------------------
578:
1.110 gdt 579: Minor version upgrades are trivial. Just rebuild/replace the
580: xenkernel version and copy the new xen.gz to / (where /boot.cfg
581: references it), and reboot.
582:
583: Major version upgrades are conceptually not difficult, but can run
584: into all the issues found when installing Xen. Assuming migration
585: from 4.1 to 4.2, remove the xenkernel41 and xentools41 packages and
586: install the xenkernel42 and xentools42 packages. Copy the 4.2 xen.gz
587: to /.
1.21 gdt 588:
1.102 gdt 589: Ensure that the contents of /etc/rc.d/xen* are correct. Specifically,
590: they must match the package you just installed and not be left over
591: from some previous installation.
592:
593: Enable the correct set of daemons; see the configuring section above.
594: (Upgrading from 3.x to 4.x without doing this will result in a hang.)
595:
596: Ensure that the domU config files are valid for the new version.
1.110 gdt 597: Specifically, for 4.x remove autorestart=True, and ensure that disks
598: are specified with numbers as the second argument, as the examples
599: above show, and not NetBSD device names.
1.15 gdt 600:
1.97 gdt 601: Hardware known to work
602: ----------------------
603:
604: Arguably, this section is misplaced, and there should be a page of
605: hardware that runs NetBSD/amd64 well, with the mostly-well-founded
606: assumption that NetBSD/xen runs fine on any modern hardware that
1.129 gdt 607: NetBSD/amd64 runs well on. Until then, we give motherboard/CPU (and
608: sometimes RAM) pairs/triples to aid those choosing a motherboard.
609: Note that Xen systems usually do not run X, so a listing here does not
610: imply that X works at all.
1.97 gdt 611:
612: Supermicro X9SRL-F, Xeon E5-1650 v2, 96 GiB ECC
613: Supermicro ??, Atom C2758 (8 core), 32 GiB ECC
614: ASUS M5A78L-M/USB3 AM3+ microATX, AMD Piledriver X8 4000MHz, 16 GiB ECC
615:
616: Older hardware:
617:
1.98 gdt 618: Intel D915GEV, Pentium4 CPU 3.40GHz, 4GB 533MHz Synchronous DDR2
1.129 gdt 619: INTEL DG33FB, "Intel(R) Core(TM)2 Duo CPU E6850 @ 3.00GHz"
620: INTEL DG33FB, "Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz"
1.28 gdt 621:
1.82 gdt 622: Running Xen under qemu
623: ----------------------
624:
625: The astute reader will note that this section is somewhat twisted.
626: However, it can be useful to run Xen under qemu either because the
627: version of NetBSD as a dom0 does not run on the hardware in use, or to
628: generate automated test cases involving Xen.
629:
1.84 gdt 630: In 2015-01, the following combination was reported to mostly work:
1.82 gdt 631:
632: host OS: NetBSD/amd64 6.1.4
633: qemu: 2.2.0 from pkgsrc
634: Xen kernel: xenkernel42-4.2.5nb1 from pkgsrc
635: dom0 kernel: NetBSD/amd64 6.1.5
636: Xen tools: xentools42-4.2.5 from pkgsrc
637:
1.91 gdt 638: See [PR 47720](http://gnats.netbsd.org/47720) for a problem with dom0
639: shutdown.
1.84 gdt 640:
1.28 gdt 641: Unprivileged domains (domU)
642: ===========================
643:
644: This section describes general concepts about domUs. It does not
1.33 gdt 645: address specific domU operating systems or how to install them. The
646: config files for domUs are typically in /usr/pkg/etc/xen, and are
1.60 wiki 647: typically named so that the file name, domU name and the domU's host
1.33 gdt 648: name match.
649:
1.111 wiz 650: The domU is provided with CPU and memory by Xen, configured by the
1.33 gdt 651: dom0. The domU is provided with disk and network by the dom0,
652: mediated by Xen, and configured in the dom0.
653:
654: Entropy in domUs can be an issue; physical disks and network are on
655: the dom0. NetBSD's /dev/random system works, but is often challenged.
656:
1.48 gdt 657: Config files
658: ------------
659:
660: There is no good order to present config files and the concepts
661: surrounding what is being configured. We first show an example config
662: file, and then in the various sections give details.
663:
664: See (at least in xentools41) /usr/pkg/share/examples/xen/xmexample*,
665: for a large number of well-commented examples, mostly for running
666: GNU/Linux.
667:
668: The following is an example minimal domain configuration file
669: "/usr/pkg/etc/xen/foo". It is (with only a name change) an actual
670: known working config file on Xen 4.1 (NetBSD 5 amd64 dom0 and NetBSD 5
671: i386 domU). The domU serves as a network file server.
672:
673: # -*- mode: python; -*-
674:
675: kernel = "/netbsd-XEN3PAE_DOMU-i386-foo.gz"
676: memory = 1024
677: vif = [ 'mac=aa:00:00:d1:00:09,bridge=bridge0' ]
678: disk = [ 'file:/n0/xen/foo-wd0,0x0,w',
679: 'file:/n0/xen/foo-wd1,0x1,w' ]
680:
681: The domain will have the same name as the file. The kernel has the
682: host/domU name in it, so that on the dom0 one can update the various
683: domUs independently. The vif line causes an interface to be provided,
684: with a specific mac address (do not reuse MAC addresses!), in bridge
685: mode. Two disks are provided, and they are both writable; the bits
686: are stored in files and Xen attaches them to a vnd(4) device in the
1.111 wiz 687: dom0 on domain creation. The system treats xbd0 as the boot device
1.48 gdt 688: without needing explicit configuration.
689:
690: By default xm looks for domain config files in /usr/pkg/etc/xen. Note
691: that "xm create" takes the name of a config file, while other commands
692: take the name of a domain. To create the domain, connect to the
693: console, create the domain while attaching the console, shutdown the
694: domain, and see if it has finished stopping, do (or xl with Xen >=
695: 4.2):
696:
697: xm create foo
698: xm console foo
699: xm create -c foo
700: xm shutdown foo
1.90 gdt 701: xm list
1.48 gdt 702:
703: Typing ^] will exit the console session. Shutting down a domain is
704: equivalent to pushing the power button; a NetBSD domU will receive a
705: power-press event and do a clean shutdown. Shutting down the dom0
706: will trigger controlled shutdowns of all configured domUs.
707:
708: domU kernels
709: ------------
710:
711: On a physical computer, the BIOS reads sector 0, and a chain of boot
712: loaders finds and loads a kernel. Normally this comes from the root
1.111 wiz 713: file system. With Xen domUs, the process is totally different. The
1.48 gdt 714: normal path is for the domU kernel to be a file in the dom0's
1.111 wiz 715: file system. At the request of the dom0, Xen loads that kernel into a
1.48 gdt 716: new domU instance and starts execution. While domU kernels can be
717: anyplace, reasonable places to store domU kernels on the dom0 are in /
718: (so they are near the dom0 kernel), in /usr/pkg/etc/xen (near the
719: config files), or in /u0/xen (where the vdisks are).
720:
1.59 gdt 721: Note that loading the domU kernel from the dom0 implies that boot
722: blocks, /boot, /boot.cfg, and so on are all ignored in the domU.
1.48 gdt 723: See the VPS section near the end for discussion of alternate ways to
724: obtain domU kernels.
725:
1.33 gdt 726: CPU and memory
727: --------------
728:
1.48 gdt 729: A domain is provided with some number of vcpus, less than the number
1.111 wiz 730: of CPUs seen by the hypervisor. (For a dom0, this is controlled by
1.48 gdt 731: the boot argument "dom0_max_vcpus=1".) For a domU, it is controlled
732: from the config file by the "vcpus = N" directive.
733:
734: A domain is provided with memory; this is controlled in the config
735: file by "memory = N" (in megabytes). In the straightforward case, the
736: sum of the the memory allocated to the dom0 and all domUs must be less
1.33 gdt 737: than the available memory.
738:
739: Xen also provides a "balloon" driver, which can be used to let domains
740: use more memory temporarily. TODO: Explain better, and explain how
741: well it works with NetBSD.
1.28 gdt 742:
743: Virtual disks
744: -------------
745:
1.33 gdt 746: With the file/vnd style, typically one creates a directory,
747: e.g. /u0/xen, on a disk large enough to hold virtual disks for all
748: domUs. Then, for each domU disk, one writes zeros to a file that then
749: serves to hold the virtual disk's bits; a suggested name is foo-xbd0
750: for the first virtual disk for the domU called foo. Writing zeros to
751: the file serves two purposes. One is that preallocating the contents
752: improves performance. The other is that vnd on sparse files has
753: failed to work. TODO: give working/notworking NetBSD versions for
1.127 gdt 754: sparse vnd and gnats reference. Note that the use of file/vnd for Xen
755: is not really different than creating a file-backed virtual disk for
756: some other purpose, except that xentools handles the vnconfig
757: commands. To create an empty 4G virtual disk, simply do
1.39 gdt 758:
759: dd if=/dev/zero of=foo-xbd0 bs=1m count=4096
1.33 gdt 760:
1.89 gdt 761: Do not use qemu-img-xen, because this will create sparse file. There
762: have been recent (2015) reports of sparse vnd(4) devices causing
763: lockups, but there is apparently no PR.
764:
1.33 gdt 765: With the lvm style, one creates logical devices. They are then used
1.48 gdt 766: similarly to vnds. TODO: Add an example with lvm.
767:
768: In domU config files, the disks are defined as a sequence of 3-tuples.
769: The first element is "method:/path/to/disk". Common methods are
770: "file:" for file-backed vnd. and "phy:" for something that is already
771: a (TODO: character or block) device.
772:
773: The second element is an artifact of how virtual disks are passed to
774: Linux, and a source of confusion with NetBSD Xen usage. Linux domUs
775: are given a device name to associate with the disk, and values like
776: "hda1" or "sda1" are common. In a NetBSD domU, the first disk appears
777: as xbd0, the second as xbd1, and so on. However, xm/xl demand a
778: second argument. The name given is converted to a major/minor by
1.49 gdt 779: calling stat(2) on the name in /dev and this is passed to the domU.
780: In the general case, the dom0 and domU can be different operating
1.48 gdt 781: systems, and it is an unwarranted assumption that they have consistent
782: numbering in /dev, or even that the dom0 OS has a /dev. With NetBSD
783: as both dom0 and domU, using values of 0x0 for the first disk and 0x1
1.49 gdt 784: for the second works fine and avoids this issue. For a GNU/Linux
785: guest, one can create /dev/hda1 in /dev, or to pass 0x301 for
786: /dev/hda1.
1.48 gdt 787:
788: The third element is "w" for writable disks, and "r" for read-only
789: disks.
1.28 gdt 790:
1.127 gdt 791: Note that NetBSD by default creates only vnd[0123]. If you need more
792: than 4 total virtual disks at a time, run e.g. "./MAKEDEV vnd4" in the
793: dom0.
794:
795: Note that NetBSD by default creates only xbd[0123]. If you need more
796: virtual disks in a domU, run e.g. "./MAKEDEV xbd4" in the domU.
797:
1.28 gdt 798: Virtual Networking
799: ------------------
800:
1.111 wiz 801: Xen provides virtual Ethernets, each of which connects the dom0 and a
1.46 gdt 802: domU. For each virtual network, there is an interface "xvifN.M" in
803: the dom0, and in domU index N, a matching interface xennetM (NetBSD
804: name). The interfaces behave as if there is an Ethernet with two
1.111 wiz 805: adapters connected. From this primitive, one can construct various
1.46 gdt 806: configurations. We focus on two common and useful cases for which
807: there are existing scripts: bridging and NAT.
1.28 gdt 808:
1.48 gdt 809: With bridging (in the example above), the domU perceives itself to be
810: on the same network as the dom0. For server virtualization, this is
811: usually best. Bridging is accomplished by creating a bridge(4) device
812: and adding the dom0's physical interface and the various xvifN.0
813: interfaces to the bridge. One specifies "bridge=bridge0" in the domU
814: config file. The bridge must be set up already in the dom0; an
815: example /etc/ifconfig.bridge0 is:
1.46 gdt 816:
817: create
818: up
819: !brconfig bridge0 add wm0
1.28 gdt 820:
821: With NAT, the domU perceives itself to be behind a NAT running on the
822: dom0. This is often appropriate when running Xen on a workstation.
1.48 gdt 823: TODO: NAT appears to be configured by "vif = [ '' ]".
1.28 gdt 824:
1.49 gdt 825: The MAC address specified is the one used for the interface in the new
1.53 gdt 826: domain. The interface in dom0 will use this address XOR'd with
1.49 gdt 827: 00:00:00:01:00:00. Random MAC addresses are assigned if not given.
828:
1.33 gdt 829: Sizing domains
830: --------------
831:
832: Modern x86 hardware has vast amounts of resources. However, many
833: virtual servers can function just fine on far less. A system with
834: 256M of RAM and a 4G disk can be a reasonable choice. Note that it is
835: far easier to adjust virtual resources than physical ones. For
836: memory, it's just a config file edit and a reboot. For disk, one can
837: create a new file and vnconfig it (or lvm), and then dump/restore,
838: just like updating physical disks, but without having to be there and
839: without those pesky connectors.
840:
1.48 gdt 841: Starting domains automatically
842: ------------------------------
1.28 gdt 843:
1.48 gdt 844: To start domains foo at bar at boot and shut them down cleanly on dom0
845: shutdown, in rc.conf add:
1.28 gdt 846:
1.48 gdt 847: xendomains="foo bar"
1.28 gdt 848:
1.111 wiz 849: Note that earlier versions of the xentools41 xendomains rc.d script
850: used xl, when one should use xm with 4.1.
1.28 gdt 851:
852: Creating specific unprivileged domains (domU)
853: =============================================
1.14 gdt 854:
855: Creating domUs is almost entirely independent of operating system. We
1.49 gdt 856: have already presented the basics of config files. Note that you must
857: have already completed the dom0 setup so that "xl list" (or "xm list")
858: works.
1.14 gdt 859:
860: Creating an unprivileged NetBSD domain (domU)
861: ---------------------------------------------
1.1 mspo 862:
1.49 gdt 863: See the earlier config file, and adjust memory. Decide on how much
864: storage you will provide, and prepare it (file or lvm).
865:
1.111 wiz 866: While the kernel will be obtained from the dom0 file system, the same
1.49 gdt 867: file should be present in the domU as /netbsd so that tools like
868: savecore(8) can work. (This is helpful but not necessary.)
869:
870: The kernel must be specifically for Xen and for use as a domU. The
871: i386 and amd64 provide the following kernels:
872:
873: i386 XEN3_DOMU
874: i386 XEN3PAE_DOMU
1.95 gdt 875: amd64 XEN3_DOMU
1.5 mspo 876:
1.49 gdt 877: Unless using Xen 3.1 (and you shouldn't) with i386-mode Xen, you must
878: use the PAE version of the i386 kernel.
879:
880: This will boot NetBSD, but this is not that useful if the disk is
881: empty. One approach is to unpack sets onto the disk outside of xen
882: (by mounting it, just as you would prepare a physical disk for a
883: system you can't run the installer on).
884:
885: A second approach is to run an INSTALL kernel, which has a miniroot
886: and can load sets from the network. To do this, copy the INSTALL
887: kernel to / and change the kernel line in the config file to:
1.5 mspo 888:
1.49 gdt 889: kernel = "/home/bouyer/netbsd-INSTALL_XEN3_DOMU"
1.5 mspo 890:
1.49 gdt 891: Then, start the domain as "xl create -c configname".
1.1 mspo 892:
1.49 gdt 893: Alternatively, if you want to install NetBSD/Xen with a CDROM image, the following
894: line should be used in the config file.
1.1 mspo 895:
1.3 mspo 896: disk = [ 'phy:/dev/wd0e,0x1,w', 'phy:/dev/cd0a,0x2,r' ]
1.1 mspo 897:
898: After booting the domain, the option to install via CDROM may be
1.49 gdt 899: selected. The CDROM device should be changed to `xbd1d`.
1.1 mspo 900:
1.49 gdt 901: Once done installing, "halt -p" the new domain (don't reboot or halt,
902: it would reload the INSTALL_XEN3_DOMU kernel even if you changed the
903: config file), switch the config file back to the XEN3_DOMU kernel,
904: and start the new domain again. Now it should be able to use "root on
905: xbd0a" and you should have a, functional NetBSD domU.
1.1 mspo 906:
1.49 gdt 907: TODO: check if this is still accurate.
1.1 mspo 908: When the new domain is booting you'll see some warnings about *wscons*
909: and the pseudo-terminals. These can be fixed by editing the files
1.5 mspo 910: `/etc/ttys` and `/etc/wscons.conf`. You must disable all terminals in
911: `/etc/ttys`, except *console*, like this:
1.1 mspo 912:
1.3 mspo 913: console "/usr/libexec/getty Pc" vt100 on secure
914: ttyE0 "/usr/libexec/getty Pc" vt220 off secure
915: ttyE1 "/usr/libexec/getty Pc" vt220 off secure
916: ttyE2 "/usr/libexec/getty Pc" vt220 off secure
917: ttyE3 "/usr/libexec/getty Pc" vt220 off secure
1.1 mspo 918:
1.5 mspo 919: Finally, all screens must be commented out from `/etc/wscons.conf`.
1.1 mspo 920:
921: It is also desirable to add
922:
1.49 gdt 923: powerd=YES
1.1 mspo 924:
1.5 mspo 925: in rc.conf. This way, the domain will be properly shut down if
1.53 gdt 926: `xm shutdown -R` or `xm shutdown -H` is used on the dom0.
1.1 mspo 927:
1.92 gdt 928: It is not strictly necessary to have a kernel (as /netbsd) in the domU
1.111 wiz 929: file system. However, various programs (e.g. netstat) will use that
1.92 gdt 930: kernel to look up symbols to read from kernel virtual memory. If
931: /netbsd is not the running kernel, those lookups will fail. (This is
932: not really a Xen-specific issue, but because the domU kernel is
933: obtained from the dom0, it is far more likely to be out of sync or
934: missing with Xen.)
935:
1.14 gdt 936: Creating an unprivileged Linux domain (domU)
1.5 mspo 937: --------------------------------------------
1.1 mspo 938:
939: Creating unprivileged Linux domains isn't much different from
940: unprivileged NetBSD domains, but there are some details to know.
941:
942: First, the second parameter passed to the disk declaration (the '0x1' in
943: the example below)
944:
1.3 mspo 945: disk = [ 'phy:/dev/wd0e,0x1,w' ]
1.1 mspo 946:
947: does matter to Linux. It wants a Linux device number here (e.g. 0x300
1.49 gdt 948: for hda). Linux builds device numbers as: (major \<\< 8 + minor).
949: So, hda1 which has major 3 and minor 1 on a Linux system will have
950: device number 0x301. Alternatively, devices names can be used (hda,
951: hdb, ...) as xentools has a table to map these names to devices
952: numbers. To export a partition to a Linux guest we can use:
1.1 mspo 953:
1.49 gdt 954: disk = [ 'phy:/dev/wd0e,0x300,w' ]
955: root = "/dev/hda1 ro"
1.1 mspo 956:
957: and it will appear as /dev/hda on the Linux system, and be used as root
958: partition.
959:
1.49 gdt 960: To install the Linux system on the partition to be exported to the
961: guest domain, the following method can be used: install
962: sysutils/e2fsprogs from pkgsrc. Use mke2fs to format the partition
963: that will be the root partition of your Linux domain, and mount it.
964: Then copy the files from a working Linux system, make adjustments in
965: `/etc` (fstab, network config). It should also be possible to extract
966: binary packages such as .rpm or .deb directly to the mounted partition
967: using the appropriate tool, possibly running under NetBSD's Linux
1.111 wiz 968: emulation. Once the file system has been populated, umount it. If
969: desirable, the file system can be converted to ext3 using tune2fs -j.
1.49 gdt 970: It should now be possible to boot the Linux guest domain, using one of
971: the vmlinuz-\*-xenU kernels available in the Xen binary distribution.
1.1 mspo 972:
1.111 wiz 973: To get the Linux console right, you need to add:
1.1 mspo 974:
1.3 mspo 975: extra = "xencons=tty1"
1.1 mspo 976:
1.111 wiz 977: to your configuration since not all Linux distributions auto-attach a
1.1 mspo 978: tty to the xen console.
979:
1.14 gdt 980: Creating an unprivileged Solaris domain (domU)
1.5 mspo 981: ----------------------------------------------
1.1 mspo 982:
1.50 gdt 983: See possibly outdated
984: [Solaris domU instructions](/ports/xen/howto-solaris/).
1.5 mspo 985:
1.1 mspo 986:
1.52 gdt 987: PCI passthrough: Using PCI devices in guest domains
988: ---------------------------------------------------
1.1 mspo 989:
1.53 gdt 990: The dom0 can give other domains access to selected PCI
1.52 gdt 991: devices. This can allow, for example, a non-privileged domain to have
992: access to a physical network interface or disk controller. However,
993: keep in mind that giving a domain access to a PCI device most likely
994: will give the domain read/write access to the whole physical memory,
995: as PCs don't have an IOMMU to restrict memory access to DMA-capable
1.53 gdt 996: device. Also, it's not possible to export ISA devices to non-dom0
1.52 gdt 997: domains, which means that the primary VGA adapter can't be exported.
998: A guest domain trying to access the VGA registers will panic.
999:
1.53 gdt 1000: If the dom0 is NetBSD, it has to be running Xen 3.1, as support has
1.52 gdt 1001: not been ported to later versions at this time.
1002:
1003: For a PCI device to be exported to a domU, is has to be attached to
1004: the "pciback" driver in dom0. Devices passed to the dom0 via the
1005: pciback.hide boot parameter will attach to "pciback" instead of the
1006: usual driver. The list of devices is specified as "(bus:dev.func)",
1.5 mspo 1007: where bus and dev are 2-digit hexadecimal numbers, and func a
1008: single-digit number:
1.1 mspo 1009:
1.52 gdt 1010: pciback.hide=(00:0a.0)(00:06.0)
1.1 mspo 1011:
1.52 gdt 1012: pciback devices should show up in the dom0's boot messages, and the
1.5 mspo 1013: devices should be listed in the `/kern/xen/pci` directory.
1.1 mspo 1014:
1.52 gdt 1015: PCI devices to be exported to a domU are listed in the "pci" array of
1016: the domU's config file, with the format "0000:bus:dev.func".
1.1 mspo 1017:
1.52 gdt 1018: pci = [ '0000:00:06.0', '0000:00:0a.0' ]
1.1 mspo 1019:
1.52 gdt 1020: In the domU an "xpci" device will show up, to which one or more pci
1.111 wiz 1021: buses will attach. Then the PCI drivers will attach to PCI buses as
1.52 gdt 1022: usual. Note that the default NetBSD DOMU kernels do not have "xpci"
1023: or any PCI drivers built in by default; you have to build your own
1024: kernel to use PCI devices in a domU. Here's a kernel config example;
1025: note that only the "xpci" lines are unusual.
1026:
1027: include "arch/i386/conf/XEN3_DOMU"
1028:
1.111 wiz 1029: # Add support for PCI buses to the XEN3_DOMU kernel
1.52 gdt 1030: xpci* at xenbus ?
1031: pci* at xpci ?
1032:
1033: # PCI USB controllers
1034: uhci* at pci? dev ? function ? # Universal Host Controller (Intel)
1035:
1036: # USB bus support
1037: usb* at uhci?
1038:
1039: # USB Hubs
1040: uhub* at usb?
1041: uhub* at uhub? port ? configuration ? interface ?
1042:
1043: # USB Mass Storage
1044: umass* at uhub? port ? configuration ? interface ?
1045: wd* at umass?
1046: # SCSI controllers
1047: ahc* at pci? dev ? function ? # Adaptec [23]94x, aic78x0 SCSI
1048:
1049: # SCSI bus support (for both ahc and umass)
1050: scsibus* at scsi?
1051:
1052: # SCSI devices
1053: sd* at scsibus? target ? lun ? # SCSI disk drives
1054: cd* at scsibus? target ? lun ? # SCSI CD-ROM drives
1.1 mspo 1055:
1056:
1.28 gdt 1057: NetBSD as a domU in a VPS
1058: =========================
1059:
1060: The bulk of the HOWTO is about using NetBSD as a dom0 on your own
1061: hardware. This section explains how to deal with Xen in a domU as a
1062: virtual private server where you do not control or have access to the
1.70 gdt 1063: dom0. This is not intended to be an exhaustive list of VPS providers;
1064: only a few are mentioned that specifically support NetBSD.
1.28 gdt 1065:
1.52 gdt 1066: VPS operators provide varying degrees of access and mechanisms for
1067: configuration. The big issue is usually how one controls which kernel
1.111 wiz 1068: is booted, because the kernel is nominally in the dom0 file system (to
1069: which VPS users do not normally have access). A second issue is how
1.70 gdt 1070: to install NetBSD.
1.52 gdt 1071: A VPS user may want to compile a kernel for security updates, to run
1072: npf, run IPsec, or any other reason why someone would want to change
1073: their kernel.
1074:
1.111 wiz 1075: One approach is to have an administrative interface to upload a kernel,
1.68 gdt 1076: or to select from a prepopulated list. Other approaches are pygrub
1.59 gdt 1077: (deprecated) and pvgrub, which are ways to have a bootloader obtain a
1.111 wiz 1078: kernel from the domU file system. This is closer to a regular physical
1.59 gdt 1079: computer, where someone who controls a machine can replace the kernel.
1.52 gdt 1080:
1.74 gdt 1081: A second issue is multiple CPUs. With NetBSD 6, domUs support
1082: multiple vcpus, and it is typical for VPS providers to enable multiple
1083: CPUs for NetBSD domUs.
1084:
1.68 gdt 1085: pygrub
1.59 gdt 1086: -------
1.52 gdt 1087:
1.111 wiz 1088: pygrub runs in the dom0 and looks into the domU file system. This
1089: implies that the domU must have a kernel in a file system in a format
1.68 gdt 1090: known to pygrub. As of 2014, pygrub seems to be of mostly historical
1091: interest.
1.52 gdt 1092:
1.59 gdt 1093: pvgrub
1094: ------
1095:
1096: pvgrub is a version of grub that uses PV operations instead of BIOS
1097: calls. It is booted from the dom0 as the domU kernel, and then reads
1.111 wiz 1098: /grub/menu.lst and loads a kernel from the domU file system.
1.59 gdt 1099:
1.70 gdt 1100: [Panix](http://www.panix.com/) lets users use pvgrub. Panix reports
1.71 gdt 1101: that pvgrub works with FFsv2 with 16K/2K and 32K/4K block/frag sizes
1102: (and hence with defaults from "newfs -O 2"). See [Panix's pvgrub
1.70 gdt 1103: page](http://www.panix.com/v-colo/grub.html), which describes only
1.74 gdt 1104: Linux but should be updated to cover NetBSD :-).
1.70 gdt 1105:
1106: [prgmr.com](http://prgmr.com/) also lets users with pvgrub to boot
1107: their own kernel. See then [prgmr.com NetBSD
1.74 gdt 1108: HOWTO](http://wiki.prgmr.com/mediawiki/index.php/NetBSD_as_a_DomU)
1109: (which is in need of updating).
1.59 gdt 1110:
1.70 gdt 1111: It appears that [grub's FFS
1112: code](http://xenbits.xensource.com/hg/xen-unstable.hg/file/bca284f67702/tools/libfsimage/ufs/fsys_ufs.c)
1113: does not support all aspects of modern FFS, but there are also reports
1.72 gdt 1114: that FFSv2 works fine. At prgmr, typically one has an ext2 or FAT
1.70 gdt 1115: partition for the kernel with the intent that grub can understand it,
1116: which leads to /netbsd not being the actual kernel. One must remember
1.111 wiz 1117: to update the special boot partition.
1.59 gdt 1118:
1119: Amazon
1120: ------
1121:
1.95 gdt 1122: See the [Amazon EC2 page](../amazon_ec2/).
1.44 gdt 1123:
1124: Using npf
1125: ---------
1126:
1.81 gdt 1127: In standard kernels, npf is a module, and thus cannot be loaded in a
1.44 gdt 1128: DOMU kernel.
1129:
1.95 gdt 1130: TODO: Explain how to compile npf into a custom kernel, answering (but
1131: note that the problem was caused by not booting the right kernel)
1132: [this email to
1133: netbsd-users](http://mail-index.netbsd.org/netbsd-users/2014/12/26/msg015576.html).
1.65 gdt 1134:
1135: TODO items for improving NetBSD/xen
1136: ===================================
1137:
1.93 gdt 1138: * Make the NetBSD dom0 kernel work with SMP.
1139: * Test the Xen 4.5 packages adequately to be able to recommend them as
1140: the standard approach.
1141: * Get PCI passthrough working on Xen 4.5
1.65 gdt 1142: * Get pvgrub into pkgsrc, either via xentools or separately.
1143: * grub
1.70 gdt 1144: * Check/add support to pkgsrc grub2 for UFS2 and arbitrary
1.66 gdt 1145: fragsize/blocksize (UFS2 support may be present; the point is to
1.111 wiz 1146: make it so that with any UFS1/UFS2 file system setup that works
1.66 gdt 1147: with NetBSD grub will also work).
1.70 gdt 1148: See [pkg/40258](http://gnats.netbsd.org/40258).
1.65 gdt 1149: * Push patches upstream.
1150: * Get UFS2 patches into pvgrub.
1151: * Add support for PV ops to a version of /boot, and make it usable as
1152: a kernel in Xen, similar to pvgrub.
1.93 gdt 1153: * Solve somehow the issue with modules for GENERIC not being loadable
1154: in a Xen dom0 or domU kernel.
1155:
1156: Random pointers
1157: ===============
1158:
1.117 gdt 1159: This section contains links from elsewhere not yet integrated into the
1160: HOWTO, and other guides.
1.93 gdt 1161:
1162: * http://www.lumbercartel.ca/library/xen/
1163: * http://pbraun.nethence.com/doc/sysutils/xen_netbsd_dom0.html
1.117 gdt 1164: * https://gmplib.org/~tege/xen.html

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