Annotation of wikisrc/ports/xen/howto.mdwn, revision 1.170
1.144 maxv 1: [[!meta title="Xen HowTo"]]
2:
1.157 maxv 3: Xen is a Type 1 hypervisor which supports running multiple guest operating
4: systems on a single physical machine. One uses the Xen kernel to control the
5: CPU, memory and console, a dom0 operating system which mediates access to
6: other hardware (e.g., disks, network, USB), and one or more domU operating
7: systems which operate in an unprivileged virtualized environment. IO requests
8: from the domU systems are forwarded by the Xen hypervisor to the dom0 to be
9: fulfilled.
1.12 gdt 10:
1.149 maxv 11: Xen supports different styles of guest:
12:
13: [[!table data="""
14: Style of guest |Supported by NetBSD
1.150 maxv 15: PV |Yes (dom0, domU)
16: HVM |Yes (domU)
1.170 ! gdt 17: PVHVM |current-only (dom0, domU)
! 18: PVH |current-only (dom0, domU)
1.149 maxv 19: """]]
20:
21: In Para-Virtualized (PV) mode, the guest OS does not attempt to access
22: hardware directly, but instead makes hypercalls to the hypervisor; PV
1.170 ! gdt 23: guests must be specifically coded for Xen.
! 24:
! 25: In HVM mode, no guest modification is required; however, hardware
! 26: support is required, such as VT-x on Intel CPUs and SVM on AMD CPUs.
! 27:
! 28: In PVHVM mode, the guest mostly runs as HVM, but can use PV drivers for efficiency. See https://wiki.xen.org/wiki/PV_on_HVM
! 29:
! 30: In PVH mode, the guest uses PV interfaces for IO and native interfaces for everything else. This is also called PVHv2; see https://wiki.xenproject.org/wiki/PVH_(v2)_Domu
1.149 maxv 31:
1.27 jnemeth 32: At boot, the dom0 kernel is loaded as a module with Xen as the kernel.
1.12 gdt 33: The dom0 can start one or more domUs. (Booting is explained in detail
34: in the dom0 section.)
35:
36: This HOWTO presumes a basic familiarity with the Xen system
1.123 gdt 37: architecture, with installing NetBSD on i386/amd64 hardware, and with
38: installing software from pkgsrc. See also the [Xen
39: website](http://www.xenproject.org/).
1.1 mspo 40:
1.160 maxv 41: [[!toc]]
1.150 maxv 42:
1.160 maxv 43: #Versions and Support
1.15 gdt 44:
1.111 wiz 45: In NetBSD, Xen is provided in pkgsrc, via matching pairs of packages
1.15 gdt 46: xenkernel and xentools. We will refer only to the kernel versions,
47: but note that both packages must be installed together and must have
48: matching versions.
49:
1.145 maxv 50: Versions available in pkgsrc:
1.85 gdt 51:
1.145 maxv 52: [[!table data="""
1.166 gdt 53: Xen Version |Package Name |Xen CPU Support |xm? |EOL'ed By Upstream
1.167 gdt 54: 4.2 |xenkernel42 |i386 x86_64 |yes |Yes
55: 4.5 |xenkernel45 |x86_64 | |Yes
56: 4.6 |xenkernel46 |x86_64 | |Yes
57: 4.8 |xenkernel48 |x86_64 | |Yes
58: 4.11 |xenkernel411 |x86_64 | |No
1.145 maxv 59: """]]
1.113 gdt 60:
1.96 gdt 61: See also the [Xen Security Advisory page](http://xenbits.xen.org/xsa/).
62:
1.157 maxv 63: Multiprocessor (SMP) support in NetBSD differs depending on the domain:
1.145 maxv 64:
1.157 maxv 65: [[!table data="""
66: Domain |Supports SMP
67: dom0 |No
68: domU |Yes
69: """]]
1.15 gdt 70:
1.167 gdt 71: Note: NetBSD support is called XEN3. However, it does support Xen 4,
1.147 maxv 72: because the hypercall interface has remained identical.
73:
1.166 gdt 74: Older Xen had a python-based management tool called xm, now replaced
75: by xl. xm is obsolete, but 4.2 remains in pkgsrc because migrating
76: from xm to xl is not always trivial, and because 4.2 is the last
77: version to run on an i386 dom0.
78:
1.18 gdt 79: Architecture
80: ------------
81:
1.167 gdt 82: Xen 4.5 and later runs on x86_64 hardware (the NetBSD amd64 port).
83: Xen 4.2 can in theory use i386 hardware, but we do not have
84: recent reports of success.
1.155 maxv 85:
86: The dom0 system, plus each domU, can be either i386PAE or amd64.
87: i386 without PAE is not supported.
88:
1.157 maxv 89: The standard approach is to use NetBSD/amd64 for the dom0.
90:
1.167 gdt 91: To use an i386PAE dom0 (other than on 4.2), one must build or obtain a
92: 64bit Xen kernel and install it on the system.
1.157 maxv 93:
94: For domUs, i386PAE is considered as
95: [faster](https://lists.xen.org/archives/html/xen-devel/2012-07/msg00085.html)
96: than amd64.
1.29 gdt 97:
1.166 gdt 98: # Creating a dom0
1.15 gdt 99:
1.158 maxv 100: In order to install a NetBSD as a dom0, one must first install a normal
101: NetBSD system, and then pivot the install to a dom0 install by changing
102: the kernel and boot configuration.
1.15 gdt 103:
1.142 gdt 104: In 2018-05, trouble booting a dom0 was reported with 256M of RAM: with
105: 512M it worked reliably. This does not make sense, but if you see
106: "not ELF" after Xen boots, try increasing dom0 RAM.
107:
1.19 gdt 108: Installation of NetBSD
109: ----------------------
1.13 gdt 110:
1.157 maxv 111: [Install NetBSD/amd64](/guide/inst/)
1.19 gdt 112: just as you would if you were not using Xen.
1.1 mspo 113:
1.19 gdt 114: Installation of Xen
115: -------------------
1.1 mspo 116:
1.155 maxv 117: We will consider that you chose to use Xen 4.8, with NetBSD/amd64 as
118: dom0. In the dom0, install xenkernel48 and xentools48 from pkgsrc.
119:
120: Once this is done, install the Xen kernel itself:
121:
122: [[!template id=programlisting text="""
123: # cp /usr/pkg/xen48-kernel/xen.gz /
124: """]]
125:
1.159 maxv 126: Then, place a NetBSD XEN3_DOM0 kernel in the `/` directory. Such kernel
127: can either be compiled manually, or downloaded from the NetBSD FTP, for
128: example at:
129:
130: [[!template id=programlisting text="""
131: ftp.netbsd.org/pub/NetBSD/NetBSD-8.0/amd64/binary/kernel/netbsd-XEN3_DOM0.gz
132: """]]
1.20 gdt 133:
1.155 maxv 134: Add a line to /boot.cfg to boot Xen:
1.20 gdt 135:
1.157 maxv 136: [[!template id=filecontent name="/boot.cfg" text="""
1.152 maxv 137: menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=512M
138: """]]
1.20 gdt 139:
1.159 maxv 140: This specifies that the dom0 should have 512MB of ram, leaving the rest
141: to be allocated for domUs. To use a serial console, use:
1.77 gdt 142:
1.157 maxv 143: [[!template id=filecontent name="/boot.cfg" text="""
1.152 maxv 144: menu=Xen:load /netbsd-XEN3_DOM0.gz;multiboot /xen.gz dom0_mem=512M console=com1 com1=9600,8n1
145: """]]
1.77 gdt 146:
147: which will use the first serial port for Xen (which counts starting
1.139 gson 148: from 1, unlike NetBSD which counts starting from 0), forcing
149: speed/parity. Because the NetBSD command line lacks a
150: "console=pc" argument, it will use the default "xencons" console device,
151: which directs the console I/O through Xen to the same console device Xen
152: itself uses (in this case, the serial port).
153:
1.157 maxv 154: In an attempt to add performance, one can also add `dom0_max_vcpus=1 dom0_vcpus_pin`,
1.37 gdt 155: to force only one vcpu to be provided (since NetBSD dom0 can't use
1.158 maxv 156: more) and to pin that vcpu to a physical CPU. Xen has
157: [many boot options](http://xenbits.xenproject.org/docs/4.8-testing/misc/xen-command-line.html),
1.111 wiz 158: and other than dom0 memory and max_vcpus, they are generally not
1.93 gdt 159: necessary.
160:
1.159 maxv 161: Copy the boot scripts into `/etc/rc.d`:
162:
163: [[!template id=programlisting text="""
164: # cp /usr/pkg/share/examples/rc.d/xen* /etc/rc.d/
165: """]]
166:
1.158 maxv 167: Enable `xencommons`:
1.31 gdt 168:
1.157 maxv 169: [[!template id=filecontent name="/etc/rc.conf" text="""
1.152 maxv 170: xencommons=YES
171: """]]
1.31 gdt 172:
1.158 maxv 173: Now, reboot so that you are running a DOM0 kernel under Xen, rather
174: than GENERIC without Xen.
1.157 maxv 175:
1.31 gdt 176: TODO: Recommend for/against xen-watchdog.
1.27 jnemeth 177:
1.158 maxv 178: Once the reboot is done, use `xl` to inspect Xen's boot messages,
1.157 maxv 179: available resources, and running domains. For example:
1.34 gdt 180:
1.153 maxv 181: [[!template id=programlisting text="""
182: # xl dmesg
183: ... xen's boot info ...
184: # xl info
185: ... available memory, etc ...
186: # xl list
187: Name Id Mem(MB) CPU State Time(s) Console
188: Domain-0 0 64 0 r---- 58.1
189: """]]
190:
191: Xen logs will be in /var/log/xen.
1.33 gdt 192:
1.88 gdt 193: ### Issues with xencommons
194:
1.157 maxv 195: `xencommons` starts `xenstored`, which stores data on behalf of dom0 and
1.88 gdt 196: domUs. It does not currently work to stop and start xenstored.
197: Certainly all domUs should be shutdown first, following the sort order
198: of the rc.d scripts. However, the dom0 sets up state with xenstored,
199: and is not notified when xenstored exits, leading to not recreating
200: the state when the new xenstored starts. Until there's a mechanism to
201: make this work, one should not expect to be able to restart xenstored
202: (and thus xencommons). There is currently no reason to expect that
203: this will get fixed any time soon.
204:
1.41 gdt 205: anita (for testing NetBSD)
206: --------------------------
207:
1.157 maxv 208: With the setup so far (assuming 4.8/xl), one should be able to run
1.82 gdt 209: anita (see pkgsrc/misc/py-anita) to test NetBSD releases, by doing (as
210: root, because anita must create a domU):
211:
1.153 maxv 212: [[!template id=programlisting text="""
213: anita --vmm=xl test file:///usr/obj/i386/
214: """]]
1.82 gdt 215:
1.40 gdt 216: Xen-specific NetBSD issues
217: --------------------------
218:
219: There are (at least) two additional things different about NetBSD as a
220: dom0 kernel compared to hardware.
221:
1.111 wiz 222: One is that the module ABI is different because some of the #defines
1.109 gdt 223: change, so one must build modules for Xen. As of netbsd-7, the build
1.157 maxv 224: system does this automatically.
1.40 gdt 225:
226: The other difference is that XEN3_DOM0 does not have exactly the same
227: options as GENERIC. While it is debatable whether or not this is a
228: bug, users should be aware of this and can simply add missing config
229: items if desired.
230:
1.15 gdt 231: Updating NetBSD in a dom0
232: -------------------------
233:
234: This is just like updating NetBSD on bare hardware, assuming the new
235: version supports the version of Xen you are running. Generally, one
236: replaces the kernel and reboots, and then overlays userland binaries
1.157 maxv 237: and adjusts `/etc`.
1.15 gdt 238:
239: Note that one must update both the non-Xen kernel typically used for
240: rescue purposes and the DOM0 kernel used with Xen.
241:
1.55 gdt 242: Converting from grub to /boot
243: -----------------------------
244:
1.157 maxv 245: These instructions were used to convert a system from
1.55 gdt 246: grub to /boot. The system was originally installed in February of
247: 2006 with a RAID1 setup and grub to boot Xen 2, and has been updated
248: over time. Before these commands, it was running NetBSD 6 i386, Xen
249: 4.1 and grub, much like the message linked earlier in the grub
250: section.
251:
1.157 maxv 252: [[!template id=programlisting text="""
253: # Install MBR bootblocks on both disks.
254: fdisk -i /dev/rwd0d
255: fdisk -i /dev/rwd1d
256: # Install NetBSD primary boot loader (/ is FFSv1) into RAID1 components.
257: installboot -v /dev/rwd0d /usr/mdec/bootxx_ffsv1
258: installboot -v /dev/rwd1d /usr/mdec/bootxx_ffsv1
259: # Install secondary boot loader
260: cp -p /usr/mdec/boot /
261: # Create boot.cfg following earlier guidance:
262: menu=Xen:load /netbsd-XEN3PAE_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=512M
263: menu=Xen.ok:load /netbsd-XEN3PAE_DOM0.ok.gz console=pc;multiboot /xen.ok.gz dom0_mem=512M
264: menu=GENERIC:boot
265: menu=GENERIC single-user:boot -s
266: menu=GENERIC.ok:boot netbsd.ok
267: menu=GENERIC.ok single-user:boot netbsd.ok -s
268: menu=Drop to boot prompt:prompt
269: default=1
270: timeout=30
271: """]]
1.22 gdt 272:
1.102 gdt 273: Upgrading Xen versions
1.15 gdt 274: ---------------------
275:
1.110 gdt 276: Minor version upgrades are trivial. Just rebuild/replace the
1.157 maxv 277: xenkernel version and copy the new xen.gz to `/` (where `/boot.cfg`
1.110 gdt 278: references it), and reboot.
279:
1.160 maxv 280: #Unprivileged domains (domU)
1.28 gdt 281:
282: This section describes general concepts about domUs. It does not
1.33 gdt 283: address specific domU operating systems or how to install them. The
1.157 maxv 284: config files for domUs are typically in `/usr/pkg/etc/xen`, and are
1.60 wiki 285: typically named so that the file name, domU name and the domU's host
1.33 gdt 286: name match.
287:
1.111 wiz 288: The domU is provided with CPU and memory by Xen, configured by the
1.33 gdt 289: dom0. The domU is provided with disk and network by the dom0,
290: mediated by Xen, and configured in the dom0.
291:
292: Entropy in domUs can be an issue; physical disks and network are on
293: the dom0. NetBSD's /dev/random system works, but is often challenged.
294:
1.48 gdt 295: Config files
296: ------------
297:
1.165 gson 298: See /usr/pkg/share/examples/xen/xlexample*
1.164 gson 299: for a small number of well-commented examples, mostly for running
1.48 gdt 300: GNU/Linux.
301:
1.157 maxv 302: The following is an example minimal domain configuration file. The domU
303: serves as a network file server.
304:
305: [[!template id=filecontent name="/usr/pkg/etc/xen/foo" text="""
306: name = "domU-id"
307: kernel = "/netbsd-XEN3PAE_DOMU-i386-foo.gz"
308: memory = 1024
309: vif = [ 'mac=aa:00:00:d1:00:09,bridge=bridge0' ]
310: disk = [ 'file:/n0/xen/foo-wd0,0x0,w',
311: 'file:/n0/xen/foo-wd1,0x1,w' ]
312: """]]
1.48 gdt 313:
1.157 maxv 314: The domain will have name given in the `name` setting. The kernel has the
1.48 gdt 315: host/domU name in it, so that on the dom0 one can update the various
1.157 maxv 316: domUs independently. The `vif` line causes an interface to be provided,
1.48 gdt 317: with a specific mac address (do not reuse MAC addresses!), in bridge
318: mode. Two disks are provided, and they are both writable; the bits
319: are stored in files and Xen attaches them to a vnd(4) device in the
1.111 wiz 320: dom0 on domain creation. The system treats xbd0 as the boot device
1.48 gdt 321: without needing explicit configuration.
322:
1.163 gson 323: By convention, domain config files are kept in `/usr/pkg/etc/xen`. Note
1.157 maxv 324: that "xl create" takes the name of a config file, while other commands
325: take the name of a domain.
326:
327: Examples of commands:
1.48 gdt 328:
1.157 maxv 329: [[!template id=programlisting text="""
1.163 gson 330: xl create /usr/pkg/etc/xen/foo
331: xl console domU-id
332: xl create -c /usr/pkg/etc/xen/foo
333: xl shutdown domU-id
1.157 maxv 334: xl list
335: """]]
336:
337: Typing `^]` will exit the console session. Shutting down a domain is
1.48 gdt 338: equivalent to pushing the power button; a NetBSD domU will receive a
339: power-press event and do a clean shutdown. Shutting down the dom0
340: will trigger controlled shutdowns of all configured domUs.
341:
1.33 gdt 342: CPU and memory
343: --------------
344:
1.169 plunky 345: A domain is provided with some number of vcpus, up to the number
1.157 maxv 346: of CPUs seen by the hypervisor. For a domU, it is controlled
1.48 gdt 347: from the config file by the "vcpus = N" directive.
348:
349: A domain is provided with memory; this is controlled in the config
350: file by "memory = N" (in megabytes). In the straightforward case, the
351: sum of the the memory allocated to the dom0 and all domUs must be less
1.33 gdt 352: than the available memory.
353:
354: Xen also provides a "balloon" driver, which can be used to let domains
1.157 maxv 355: use more memory temporarily.
1.28 gdt 356:
357: Virtual disks
358: -------------
359:
1.158 maxv 360: In domU config files, the disks are defined as a sequence of 3-tuples:
361:
362: * The first element is "method:/path/to/disk". Common methods are
1.162 gutterid 363: "file:" for a file-backed vnd, and "phy:" for something that is already
364: a device, such as an LVM logical volume.
1.158 maxv 365:
366: * The second element is an artifact of how virtual disks are passed to
367: Linux, and a source of confusion with NetBSD Xen usage. Linux domUs
368: are given a device name to associate with the disk, and values like
369: "hda1" or "sda1" are common. In a NetBSD domU, the first disk appears
370: as xbd0, the second as xbd1, and so on. However, xl demands a
371: second argument. The name given is converted to a major/minor by
372: calling stat(2) on the name in /dev and this is passed to the domU.
373: In the general case, the dom0 and domU can be different operating
374: systems, and it is an unwarranted assumption that they have consistent
375: numbering in /dev, or even that the dom0 OS has a /dev. With NetBSD
376: as both dom0 and domU, using values of 0x0 for the first disk and 0x1
377: for the second works fine and avoids this issue. For a GNU/Linux
378: guest, one can create /dev/hda1 in /dev, or to pass 0x301 for
379: /dev/hda1.
1.48 gdt 380:
1.158 maxv 381: * The third element is "w" for writable disks, and "r" for read-only
382: disks.
383:
384: Example:
385: [[!template id=filecontent name="/usr/pkg/etc/xen/foo" text="""
386: disk = [ 'file:/n0/xen/foo-wd0,0x0,w' ]
387: """]]
1.28 gdt 388:
1.127 gdt 389: Note that NetBSD by default creates only vnd[0123]. If you need more
390: than 4 total virtual disks at a time, run e.g. "./MAKEDEV vnd4" in the
391: dom0.
392:
393: Note that NetBSD by default creates only xbd[0123]. If you need more
394: virtual disks in a domU, run e.g. "./MAKEDEV xbd4" in the domU.
395:
1.28 gdt 396: Virtual Networking
397: ------------------
398:
1.111 wiz 399: Xen provides virtual Ethernets, each of which connects the dom0 and a
1.46 gdt 400: domU. For each virtual network, there is an interface "xvifN.M" in
1.158 maxv 401: the dom0, and a matching interface xennetM (NetBSD name) in domU index N.
402: The interfaces behave as if there is an Ethernet with two
1.111 wiz 403: adapters connected. From this primitive, one can construct various
1.46 gdt 404: configurations. We focus on two common and useful cases for which
405: there are existing scripts: bridging and NAT.
1.28 gdt 406:
1.48 gdt 407: With bridging (in the example above), the domU perceives itself to be
408: on the same network as the dom0. For server virtualization, this is
409: usually best. Bridging is accomplished by creating a bridge(4) device
410: and adding the dom0's physical interface and the various xvifN.0
411: interfaces to the bridge. One specifies "bridge=bridge0" in the domU
412: config file. The bridge must be set up already in the dom0; an
413: example /etc/ifconfig.bridge0 is:
1.46 gdt 414:
1.157 maxv 415: [[!template id=filecontent name="/etc/ifconfig.bridge0" text="""
416: create
417: up
418: !brconfig bridge0 add wm0
419: """]]
1.28 gdt 420:
421: With NAT, the domU perceives itself to be behind a NAT running on the
422: dom0. This is often appropriate when running Xen on a workstation.
1.48 gdt 423: TODO: NAT appears to be configured by "vif = [ '' ]".
1.28 gdt 424:
1.49 gdt 425: The MAC address specified is the one used for the interface in the new
1.53 gdt 426: domain. The interface in dom0 will use this address XOR'd with
1.49 gdt 427: 00:00:00:01:00:00. Random MAC addresses are assigned if not given.
428:
1.48 gdt 429: Starting domains automatically
430: ------------------------------
1.28 gdt 431:
1.158 maxv 432: To start domains `domU-netbsd` and `domU-linux` at boot and shut them
433: down cleanly on dom0 shutdown, add the following in rc.conf:
1.28 gdt 434:
1.158 maxv 435: [[!template id=filecontent name="/etc/rc.conf" text="""
436: xendomains="domU-netbsd domU-linux"
437: """]]
1.28 gdt 438:
1.160 maxv 439: #Creating a domU
1.14 gdt 440:
441: Creating domUs is almost entirely independent of operating system. We
1.49 gdt 442: have already presented the basics of config files. Note that you must
1.158 maxv 443: have already completed the dom0 setup so that "xl list" works.
1.14 gdt 444:
1.158 maxv 445: Creating a NetBSD domU
446: ----------------------
1.1 mspo 447:
1.49 gdt 448: See the earlier config file, and adjust memory. Decide on how much
1.162 gutterid 449: storage you will provide, and prepare it (file or LVM).
1.49 gdt 450:
1.111 wiz 451: While the kernel will be obtained from the dom0 file system, the same
1.49 gdt 452: file should be present in the domU as /netbsd so that tools like
453: savecore(8) can work. (This is helpful but not necessary.)
454:
455: The kernel must be specifically for Xen and for use as a domU. The
456: i386 and amd64 provide the following kernels:
457:
458: i386 XEN3PAE_DOMU
1.95 gdt 459: amd64 XEN3_DOMU
1.5 mspo 460:
1.49 gdt 461: This will boot NetBSD, but this is not that useful if the disk is
462: empty. One approach is to unpack sets onto the disk outside of xen
463: (by mounting it, just as you would prepare a physical disk for a
464: system you can't run the installer on).
465:
466: A second approach is to run an INSTALL kernel, which has a miniroot
467: and can load sets from the network. To do this, copy the INSTALL
468: kernel to / and change the kernel line in the config file to:
1.5 mspo 469:
1.49 gdt 470: kernel = "/home/bouyer/netbsd-INSTALL_XEN3_DOMU"
1.5 mspo 471:
1.163 gson 472: Then, start the domain as "xl create -c configfile".
1.1 mspo 473:
1.49 gdt 474: Alternatively, if you want to install NetBSD/Xen with a CDROM image, the following
475: line should be used in the config file.
1.1 mspo 476:
1.3 mspo 477: disk = [ 'phy:/dev/wd0e,0x1,w', 'phy:/dev/cd0a,0x2,r' ]
1.1 mspo 478:
479: After booting the domain, the option to install via CDROM may be
1.49 gdt 480: selected. The CDROM device should be changed to `xbd1d`.
1.1 mspo 481:
1.49 gdt 482: Once done installing, "halt -p" the new domain (don't reboot or halt,
483: it would reload the INSTALL_XEN3_DOMU kernel even if you changed the
484: config file), switch the config file back to the XEN3_DOMU kernel,
485: and start the new domain again. Now it should be able to use "root on
486: xbd0a" and you should have a, functional NetBSD domU.
1.1 mspo 487:
1.49 gdt 488: TODO: check if this is still accurate.
1.1 mspo 489: When the new domain is booting you'll see some warnings about *wscons*
490: and the pseudo-terminals. These can be fixed by editing the files
1.5 mspo 491: `/etc/ttys` and `/etc/wscons.conf`. You must disable all terminals in
492: `/etc/ttys`, except *console*, like this:
1.1 mspo 493:
1.3 mspo 494: console "/usr/libexec/getty Pc" vt100 on secure
495: ttyE0 "/usr/libexec/getty Pc" vt220 off secure
496: ttyE1 "/usr/libexec/getty Pc" vt220 off secure
497: ttyE2 "/usr/libexec/getty Pc" vt220 off secure
498: ttyE3 "/usr/libexec/getty Pc" vt220 off secure
1.1 mspo 499:
1.5 mspo 500: Finally, all screens must be commented out from `/etc/wscons.conf`.
1.1 mspo 501:
502: It is also desirable to add
503:
1.49 gdt 504: powerd=YES
1.1 mspo 505:
1.5 mspo 506: in rc.conf. This way, the domain will be properly shut down if
1.53 gdt 507: `xm shutdown -R` or `xm shutdown -H` is used on the dom0.
1.1 mspo 508:
1.92 gdt 509: It is not strictly necessary to have a kernel (as /netbsd) in the domU
1.111 wiz 510: file system. However, various programs (e.g. netstat) will use that
1.92 gdt 511: kernel to look up symbols to read from kernel virtual memory. If
512: /netbsd is not the running kernel, those lookups will fail. (This is
513: not really a Xen-specific issue, but because the domU kernel is
514: obtained from the dom0, it is far more likely to be out of sync or
515: missing with Xen.)
516:
1.158 maxv 517: Creating a Linux domU
518: ---------------------
1.1 mspo 519:
520: Creating unprivileged Linux domains isn't much different from
521: unprivileged NetBSD domains, but there are some details to know.
522:
523: First, the second parameter passed to the disk declaration (the '0x1' in
524: the example below)
525:
1.3 mspo 526: disk = [ 'phy:/dev/wd0e,0x1,w' ]
1.1 mspo 527:
528: does matter to Linux. It wants a Linux device number here (e.g. 0x300
1.49 gdt 529: for hda). Linux builds device numbers as: (major \<\< 8 + minor).
530: So, hda1 which has major 3 and minor 1 on a Linux system will have
531: device number 0x301. Alternatively, devices names can be used (hda,
532: hdb, ...) as xentools has a table to map these names to devices
533: numbers. To export a partition to a Linux guest we can use:
1.1 mspo 534:
1.49 gdt 535: disk = [ 'phy:/dev/wd0e,0x300,w' ]
536: root = "/dev/hda1 ro"
1.1 mspo 537:
538: and it will appear as /dev/hda on the Linux system, and be used as root
539: partition.
540:
1.49 gdt 541: To install the Linux system on the partition to be exported to the
542: guest domain, the following method can be used: install
543: sysutils/e2fsprogs from pkgsrc. Use mke2fs to format the partition
544: that will be the root partition of your Linux domain, and mount it.
545: Then copy the files from a working Linux system, make adjustments in
546: `/etc` (fstab, network config). It should also be possible to extract
547: binary packages such as .rpm or .deb directly to the mounted partition
548: using the appropriate tool, possibly running under NetBSD's Linux
1.111 wiz 549: emulation. Once the file system has been populated, umount it. If
550: desirable, the file system can be converted to ext3 using tune2fs -j.
1.49 gdt 551: It should now be possible to boot the Linux guest domain, using one of
552: the vmlinuz-\*-xenU kernels available in the Xen binary distribution.
1.1 mspo 553:
1.111 wiz 554: To get the Linux console right, you need to add:
1.1 mspo 555:
1.3 mspo 556: extra = "xencons=tty1"
1.1 mspo 557:
1.111 wiz 558: to your configuration since not all Linux distributions auto-attach a
1.1 mspo 559: tty to the xen console.
560:
1.158 maxv 561: Creating a Solaris domU
562: -----------------------
1.1 mspo 563:
1.50 gdt 564: See possibly outdated
565: [Solaris domU instructions](/ports/xen/howto-solaris/).
1.5 mspo 566:
1.1 mspo 567:
1.52 gdt 568: PCI passthrough: Using PCI devices in guest domains
569: ---------------------------------------------------
1.1 mspo 570:
1.53 gdt 571: The dom0 can give other domains access to selected PCI
1.52 gdt 572: devices. This can allow, for example, a non-privileged domain to have
573: access to a physical network interface or disk controller. However,
574: keep in mind that giving a domain access to a PCI device most likely
575: will give the domain read/write access to the whole physical memory,
576: as PCs don't have an IOMMU to restrict memory access to DMA-capable
1.53 gdt 577: device. Also, it's not possible to export ISA devices to non-dom0
1.52 gdt 578: domains, which means that the primary VGA adapter can't be exported.
579: A guest domain trying to access the VGA registers will panic.
580:
1.53 gdt 581: If the dom0 is NetBSD, it has to be running Xen 3.1, as support has
1.52 gdt 582: not been ported to later versions at this time.
583:
584: For a PCI device to be exported to a domU, is has to be attached to
585: the "pciback" driver in dom0. Devices passed to the dom0 via the
586: pciback.hide boot parameter will attach to "pciback" instead of the
587: usual driver. The list of devices is specified as "(bus:dev.func)",
1.5 mspo 588: where bus and dev are 2-digit hexadecimal numbers, and func a
589: single-digit number:
1.1 mspo 590:
1.52 gdt 591: pciback.hide=(00:0a.0)(00:06.0)
1.1 mspo 592:
1.52 gdt 593: pciback devices should show up in the dom0's boot messages, and the
1.5 mspo 594: devices should be listed in the `/kern/xen/pci` directory.
1.1 mspo 595:
1.52 gdt 596: PCI devices to be exported to a domU are listed in the "pci" array of
597: the domU's config file, with the format "0000:bus:dev.func".
1.1 mspo 598:
1.52 gdt 599: pci = [ '0000:00:06.0', '0000:00:0a.0' ]
1.1 mspo 600:
1.52 gdt 601: In the domU an "xpci" device will show up, to which one or more pci
1.111 wiz 602: buses will attach. Then the PCI drivers will attach to PCI buses as
1.52 gdt 603: usual. Note that the default NetBSD DOMU kernels do not have "xpci"
604: or any PCI drivers built in by default; you have to build your own
605: kernel to use PCI devices in a domU. Here's a kernel config example;
606: note that only the "xpci" lines are unusual.
607:
608: include "arch/i386/conf/XEN3_DOMU"
609:
1.111 wiz 610: # Add support for PCI buses to the XEN3_DOMU kernel
1.52 gdt 611: xpci* at xenbus ?
612: pci* at xpci ?
613:
614: # PCI USB controllers
615: uhci* at pci? dev ? function ? # Universal Host Controller (Intel)
616:
617: # USB bus support
618: usb* at uhci?
619:
620: # USB Hubs
621: uhub* at usb?
622: uhub* at uhub? port ? configuration ? interface ?
623:
624: # USB Mass Storage
625: umass* at uhub? port ? configuration ? interface ?
626: wd* at umass?
627: # SCSI controllers
628: ahc* at pci? dev ? function ? # Adaptec [23]94x, aic78x0 SCSI
629:
630: # SCSI bus support (for both ahc and umass)
631: scsibus* at scsi?
632:
633: # SCSI devices
634: sd* at scsibus? target ? lun ? # SCSI disk drives
635: cd* at scsibus? target ? lun ? # SCSI CD-ROM drives
1.1 mspo 636:
637:
1.160 maxv 638: #NetBSD as a domU in a VPS
1.28 gdt 639:
640: The bulk of the HOWTO is about using NetBSD as a dom0 on your own
641: hardware. This section explains how to deal with Xen in a domU as a
642: virtual private server where you do not control or have access to the
1.70 gdt 643: dom0. This is not intended to be an exhaustive list of VPS providers;
644: only a few are mentioned that specifically support NetBSD.
1.28 gdt 645:
1.52 gdt 646: VPS operators provide varying degrees of access and mechanisms for
647: configuration. The big issue is usually how one controls which kernel
1.111 wiz 648: is booted, because the kernel is nominally in the dom0 file system (to
649: which VPS users do not normally have access). A second issue is how
1.70 gdt 650: to install NetBSD.
1.52 gdt 651: A VPS user may want to compile a kernel for security updates, to run
652: npf, run IPsec, or any other reason why someone would want to change
653: their kernel.
654:
1.111 wiz 655: One approach is to have an administrative interface to upload a kernel,
1.68 gdt 656: or to select from a prepopulated list. Other approaches are pygrub
1.59 gdt 657: (deprecated) and pvgrub, which are ways to have a bootloader obtain a
1.111 wiz 658: kernel from the domU file system. This is closer to a regular physical
1.59 gdt 659: computer, where someone who controls a machine can replace the kernel.
1.52 gdt 660:
1.74 gdt 661: A second issue is multiple CPUs. With NetBSD 6, domUs support
662: multiple vcpus, and it is typical for VPS providers to enable multiple
663: CPUs for NetBSD domUs.
664:
1.59 gdt 665: pvgrub
666: ------
667:
668: pvgrub is a version of grub that uses PV operations instead of BIOS
669: calls. It is booted from the dom0 as the domU kernel, and then reads
1.111 wiz 670: /grub/menu.lst and loads a kernel from the domU file system.
1.59 gdt 671:
1.70 gdt 672: [Panix](http://www.panix.com/) lets users use pvgrub. Panix reports
1.71 gdt 673: that pvgrub works with FFsv2 with 16K/2K and 32K/4K block/frag sizes
674: (and hence with defaults from "newfs -O 2"). See [Panix's pvgrub
1.70 gdt 675: page](http://www.panix.com/v-colo/grub.html), which describes only
1.74 gdt 676: Linux but should be updated to cover NetBSD :-).
1.70 gdt 677:
678: [prgmr.com](http://prgmr.com/) also lets users with pvgrub to boot
679: their own kernel. See then [prgmr.com NetBSD
1.74 gdt 680: HOWTO](http://wiki.prgmr.com/mediawiki/index.php/NetBSD_as_a_DomU)
681: (which is in need of updating).
1.59 gdt 682:
1.70 gdt 683: It appears that [grub's FFS
684: code](http://xenbits.xensource.com/hg/xen-unstable.hg/file/bca284f67702/tools/libfsimage/ufs/fsys_ufs.c)
685: does not support all aspects of modern FFS, but there are also reports
1.72 gdt 686: that FFSv2 works fine. At prgmr, typically one has an ext2 or FAT
1.70 gdt 687: partition for the kernel with the intent that grub can understand it,
688: which leads to /netbsd not being the actual kernel. One must remember
1.111 wiz 689: to update the special boot partition.
1.59 gdt 690:
1.168 wiki 691: pygrub
692: -------
693:
694: pygrub runs in the dom0 and looks into the domU file system. This
695: implies that the domU must have a kernel in a file system in a format
696: known to pygrub.
697:
698: pygrub doesn't seem to work to load Linux images under NetBSD dom0,
699: and is inherently less secure than pvgrub due to running inside dom0. For both these
700: reasons, pygrub should not be used, and is only still present so that
701: historical DomU images using it still work.
702:
703: As of 2014, pygrub seems to be of mostly historical
704: interest. New DomUs should use pvgrub.
705:
1.59 gdt 706: Amazon
707: ------
708:
1.143 wiki 709: See the [Amazon EC2 page](/amazon_ec2/).
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