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Diff for /wikisrc/ports/xen/howto.mdwn between versions 1.62 and 1.80

version 1.62, 2014/12/29 00:13:15	version 1.80, 2015/01/17 13:04:01
Line 100 Note that NetBSD support is called XEN3.	Line 100 Note that NetBSD support is called XEN3.
Xen command program	Xen command program
-------------------	-------------------

Early Xen used a program called "xm" to manipulate the system from the	Early Xen used a program called xm to manipulate the system from the
dom0. Starting in 4.1, a replacement program with similar behavior	dom0. Starting in 4.1, a replacement program with similar behavior
called "xl" is provided. In 4.2 and later, "xl" is preferred. 4.4 is	called xl is provided, but it does not work well in 4.1. In 4.2, both
the last version that has "xm".	xm and xl work fine. 4.4 is the last version that has xm. You must
	choose one or the other, because it affects which daemons you run.

NetBSD	NetBSD
------	------
Line 154 aging code and aging compilers, qemu (in	Line 155 aging code and aging compilers, qemu (in
support) is difficult to build. The following are known to work or FAIL:	support) is difficult to build. The following are known to work or FAIL:

xenkernel3 netbsd-5 amd64	xenkernel3 netbsd-5 amd64
	xentools3 netbsd-5 amd64
	xentools3=hvm netbsd-5 amd64 ????
xenkernel33 netbsd-5 amd64	xenkernel33 netbsd-5 amd64
	xentools33 netbsd-5 amd64
xenkernel41 netbsd-5 amd64	xenkernel41 netbsd-5 amd64
xentools41 netbsd-5 amd64	xentools41 netbsd-5 amd64
xenkernel42 netbsd-5 amd64	xenkernel42 netbsd-5 amd64
	xentools42 netbsd-5 amd64

xenkernel3 netbsd-6 i386 FAIL	xenkernel3 netbsd-6 i386 FAIL
xentools3 netbsd-6 i386	xentools3 netbsd-6 i386
xentools3-hvm netbsd-6 i386 FAIL (dependencies fail)	xentools3-hvm netbsd-6 i386 FAIL (dependencies fail)
xenkernel33 netbsd-6 i386	xenkernel33 netbsd-6 i386
xentools33 netbsd-6 i386	xentools33 netbsd-6 i386
xenkernel41 netbsd-6 i386	xenkernel41 netbsd-6 i386
xentools41 netbsd-6 i386	xentools41 netbsd-6 i386
xenkernel42 netbsd-6 i386	xenkernel42 netbsd-6 i386
xentools42 netbsd-6 i386 FAIL	xentools42 netbsd-6 i386 *MIXED

	(all 3 and 33 seem to FAIL)
	xenkernel41 netbsd-7 i386
	xentools41 netbsd-7 i386
	xenkernel42 netbsd-7 i386
	xentools42 netbsd-7 i386 ??FAIL

	(*On netbsd-6 i386, there is a xentools42 in the 2014Q3 official builds,
	but it does not build for gdt.)

NetBSD as a dom0	NetBSD as a dom0
================	================
Line 261 For debugging, one may copy xen-debug.gz	Line 275 For debugging, one may copy xen-debug.gz
to DIAGNOSTIC and DEBUG in NetBSD. xen-debug.gz is basically only	to DIAGNOSTIC and DEBUG in NetBSD. xen-debug.gz is basically only
useful with a serial console. Then, place a NetBSD XEN3_DOM0 kernel	useful with a serial console. Then, place a NetBSD XEN3_DOM0 kernel
in /, copied from releasedir/amd64/binary/kernel/netbsd-XEN3_DOM0.gz	in /, copied from releasedir/amd64/binary/kernel/netbsd-XEN3_DOM0.gz
of a NetBSD build. Both xen and NetBSD may be left compressed. (If	of a NetBSD build. If using i386, use
using i386, use releasedir/i386/binary/kernel/netbsd-XEN3PAE_DOM0.gz.)	releasedir/i386/binary/kernel/netbsd-XEN3PAE_DOM0.gz. (If using Xen
	3.1 and i386, you may use XEN3_DOM0 with the non-PAE Xen. But you
With Xen as the kernel, you must provide a dom0 NetBSD kernel to be	should not use Xen 3.1.) Both xen and the NetBSD kernel may be (and
used as a module; place this in /. Suitable kernels are provided in	typically are) left compressed.
releasedir/binary/kernel:
	In a dom0 kernel, kernfs is mandatory for xend to comunicate with the
i386 XEN3_DOM0	kernel, so ensure that /kern is in fstab. TODO: Say this is default,
i386 XEN3PAE_DOM0	or file a PR and give a reference.
amd64 XEN3_DOM0

The first one is only for use with Xen 3.1 and i386-mode Xen (and you
should not do this). Current Xen always uses PAE on i386, but you
should generally use amd64 for the dom0. In a dom0 kernel, kernfs is
mandatory for xend to comunicate with the kernel, so ensure that /kern
is in fstab. TODO: Say this is default, or file a PR and give a
reference.

Because you already installed NetBSD, you have a working boot setup	Because you already installed NetBSD, you have a working boot setup
with an MBR bootblock, either bootxx_ffsv1 or bootxx_ffsv2 at the	with an MBR bootblock, either bootxx_ffsv1 or bootxx_ffsv2 at the
beginning of your root filesystem, /boot present, and likely	beginning of your root filesystem, /boot present, and likely
/boot.cfg. (If not, fix before continuing!)	/boot.cfg. (If not, fix before continuing!)

See boot.cfg(5) for an example. The basic line is	Add a line to to /boot.cfg to boot Xen. See boot.cfg(5) for an
	example. The basic line is

menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=256M	menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=256M

which specifies that the dom0 should have 256M, leaving the rest to be	which specifies that the dom0 should have 256M, leaving the rest to be
allocated for domUs. In an attempt to add performance, one can also	allocated for domUs. To use a serial console, use
add
	menu=Xen:load /netbsd-XEN3_DOM0.gz console=com0;multiboot /xen.gz dom0_mem=256M console=com1 com1=9600,8n1

	which will use the first serial port for Xen (which counts starting
	from 1), forcing speed/parity, and also for NetBSD (which counts
	starting at 0). In an attempt to add performance, one can also add

dom0_max_vcpus=1 dom0_vcpus_pin	dom0_max_vcpus=1 dom0_vcpus_pin

Line 301 As with non-Xen systems, you should have	Line 313 As with non-Xen systems, you should have
kernel that works without Xen) and fallback versions of the non-Xen	kernel that works without Xen) and fallback versions of the non-Xen
kernel, Xen, and the dom0 kernel.	kernel, Xen, and the dom0 kernel.

	Now, reboot so that you are running a DOM0 kernel under Xen, rather
	than GENERIC without Xen.

Using grub (historic)	Using grub (historic)
---------------------	---------------------

Line 319 Configuring Xen	Line 334 Configuring Xen

Xen logs will be in /var/log/xen.	Xen logs will be in /var/log/xen.

Now, you have a system that will boot Xen and the dom0 kernel, and	Now, you have a system that will boot Xen and the dom0 kernel, but not
just run the dom0 kernel. There will be no domUs, and none can be	do anything else special. Make sure that you have rebooted into Xen.
started because you still have to configure the dom0 tools. The	There will be no domUs, and none can be started because you still have
daemons which should be run vary with Xen version and with whether one	to configure the dom0 tools. The daemons which should be run vary
is using xm or xl. Note that xend is for supporting "xm", and should	with Xen version and with whether one is using xm or xl. Note that
only be used if you plan on using "xm". Do NOT enable xend if you	xend is for supporting "xm", and should only be used if you plan on
plan on using "xl" as it will cause problems.	using "xm". Do NOT enable xend if you plan on using "xl" as it will
	cause problems.

The installation of NetBSD should already have created devices for xen	The installation of NetBSD should already have created devices for xen
(xencons, xenevt), but if they are not present, create them:	(xencons, xenevt), but if they are not present, create them:
Line 353 For 4.2 with xm, add to rc.conf	Line 369 For 4.2 with xm, add to rc.conf
xencommons=YES	xencommons=YES
xend=YES	xend=YES

For 4.2 with xl (preferred), add to rc.conf:	For 4.2 with xl, add to rc.conf:

xencommons=YES	xencommons=YES
TODO: explain if there is a xend replacement	TODO: explain if there is a xend replacement
Line 361 For 4.2 with xl (preferred), add to rc.c	Line 377 For 4.2 with xl (preferred), add to rc.c
TODO: Recommend for/against xen-watchdog.	TODO: Recommend for/against xen-watchdog.

After you have configured the daemons and either started them (in the	After you have configured the daemons and either started them (in the
order given) or rebooted, run the following (or use xl) to inspect	order given) or rebooted, use xm or xl to inspect Xen's boot messages,
Xen's boot messages, available resources, and running domains:	available resources, and running domains. An example with xm follows:

# xm dmesg	# xm dmesg
[xen's boot info]	[xen's boot info]
Line 372 Xen's boot messages, available resources	Line 388 Xen's boot messages, available resources
Name Id Mem(MB) CPU State Time(s) Console	Name Id Mem(MB) CPU State Time(s) Console
Domain-0 0 64 0 r---- 58.1	Domain-0 0 64 0 r---- 58.1

	With xl, the commands are the same, and the output may be slightly
	different. TODO: add example output for xl, after confirming on 4.2
	and resolving the TODO about rc.conf.

anita (for testing NetBSD)	anita (for testing NetBSD)
--------------------------	--------------------------

With the setup so far, one should be able to run anita (see	With the setup so far, one should be able to run anita (see
pkgsrc/sysutils/py-anita) to test NetBSD releases, by doing (as root,	pkgsrc/misc/py-anita) to test NetBSD releases, by doing (as root,
because anita must create a domU):	because anita must create a domU):

anita --vmm=xm test file:///usr/obj/i386/	anita --vmm=xm test file:///usr/obj/i386/

Alternatively, one can use --vmm=xl to use xl-based domU creation instead.	Alternatively, one can use --vmm=xl to use xl-based domU creation instead.
TODO: check this.	TODO: check this, and make the example use xl when confirmed.

Xen-specific NetBSD issues	Xen-specific NetBSD issues
--------------------------	--------------------------
Line 862 NetBSD as a domU in a VPS	Line 882 NetBSD as a domU in a VPS
The bulk of the HOWTO is about using NetBSD as a dom0 on your own	The bulk of the HOWTO is about using NetBSD as a dom0 on your own
hardware. This section explains how to deal with Xen in a domU as a	hardware. This section explains how to deal with Xen in a domU as a
virtual private server where you do not control or have access to the	virtual private server where you do not control or have access to the
dom0.	dom0. This is not intended to be an exhaustive list of VPS providers;
	only a few are mentioned that specifically support NetBSD.

VPS operators provide varying degrees of access and mechanisms for	VPS operators provide varying degrees of access and mechanisms for
configuration. The big issue is usually how one controls which kernel	configuration. The big issue is usually how one controls which kernel
is booted, because the kernel is nominally in the dom0 filesystem (to	is booted, because the kernel is nominally in the dom0 filesystem (to
which VPS users do not normally have acesss).	which VPS users do not normally have acesss). A second issue is how
	to install NetBSD.
A VPS user may want to compile a kernel for security updates, to run	A VPS user may want to compile a kernel for security updates, to run
npf, run IPsec, or any other reason why someone would want to change	npf, run IPsec, or any other reason why someone would want to change
their kernel.	their kernel.

One approach is to have an adminstrative interface to upload a kernel,	One approach is to have an adminstrative interface to upload a kernel,
or to select from a prepopulated list. Other approaches are py-grub	or to select from a prepopulated list. Other approaches are pygrub
(deprecated) and pvgrub, which are ways to have a bootloader obtain a	(deprecated) and pvgrub, which are ways to have a bootloader obtain a
kernel from the domU filesystem. This is closer to a regular physical	kernel from the domU filesystem. This is closer to a regular physical
computer, where someone who controls a machine can replace the kernel.	computer, where someone who controls a machine can replace the kernel.

py-grub	A second issue is multiple CPUs. With NetBSD 6, domUs support
	multiple vcpus, and it is typical for VPS providers to enable multiple
	CPUs for NetBSD domUs.

	pygrub
-------	-------

py-grub runs in the dom0 and looks into the domU filesystem. This	pygrub runs in the dom0 and looks into the domU filesystem. This
implies that the domU must have a kernel in a filesystem in a format	implies that the domU must have a kernel in a filesystem in a format
known to py-grub. As of 2014, py-grub seems to be of mostly historical interest.	known to pygrub. As of 2014, pygrub seems to be of mostly historical
	interest.

pvgrub	pvgrub
------	------
Line 893 pvgrub is a version of grub that uses PV	Line 919 pvgrub is a version of grub that uses PV
calls. It is booted from the dom0 as the domU kernel, and then reads	calls. It is booted from the dom0 as the domU kernel, and then reads
/grub/menu.lst and loads a kernel from the domU filesystem.	/grub/menu.lst and loads a kernel from the domU filesystem.

[prgmr.com](http://prgmr.com/) uses this approach to let users choose	[Panix](http://www.panix.com/) lets users use pvgrub. Panix reports
their own operating system and kernel. See then [prgmr.com NetBSD	that pvgrub works with FFsv2 with 16K/2K and 32K/4K block/frag sizes
HOWTO](http://wiki.prgmr.com/mediawiki/index.php/NetBSD_as_a_DomU).	(and hence with defaults from "newfs -O 2"). See [Panix's pvgrub
	page](http://www.panix.com/v-colo/grub.html), which describes only
Because [grub's FFS code](http://xenbits.xensource.com/hg/xen-unstable.hg/file/bca284f67702/tools/libfsimage/ufs/fsys_ufs.c)	Linux but should be updated to cover NetBSD :-).
appears not to support all aspects of modern FFS,
typically one has an ext2 or FAT partition for the kernel, so that	[prgmr.com](http://prgmr.com/) also lets users with pvgrub to boot
grub can understand it, which leads to /netbsd not being the actual	their own kernel. See then [prgmr.com NetBSD
kernel. One must remember to update the special boot partiion.	HOWTO](http://wiki.prgmr.com/mediawiki/index.php/NetBSD_as_a_DomU)
	(which is in need of updating).

	It appears that [grub's FFS
	code](http://xenbits.xensource.com/hg/xen-unstable.hg/file/bca284f67702/tools/libfsimage/ufs/fsys_ufs.c)
	does not support all aspects of modern FFS, but there are also reports
	that FFSv2 works fine. At prgmr, typically one has an ext2 or FAT
	partition for the kernel with the intent that grub can understand it,
	which leads to /netbsd not being the actual kernel. One must remember
	to update the special boot partiion.

Amazon	Amazon
------	------
Line 917 DOMU kernel.	Line 952 DOMU kernel.
TODO: explain how to compile npf into a custom kernel, answering (but	TODO: explain how to compile npf into a custom kernel, answering (but
note that the problem was caused by not booting the right kernel):	note that the problem was caused by not booting the right kernel):
http://mail-index.netbsd.org/netbsd-users/2014/12/26/msg015576.html	http://mail-index.netbsd.org/netbsd-users/2014/12/26/msg015576.html

	TODO items for improving NetBSD/xen
	===================================

	* Package Xen 4.4.
	* Get PCI passthrough working on Xen 4.2 (or 4.4).
	* Get pvgrub into pkgsrc, either via xentools or separately.
	* grub
	* Check/add support to pkgsrc grub2 for UFS2 and arbitrary
	fragsize/blocksize (UFS2 support may be present; the point is to
	make it so that with any UFS1/UFS2 filesystem setup that works
	with NetBSD grub will also work).
	See [pkg/40258](http://gnats.netbsd.org/40258).
	* Push patches upstream.
	* Get UFS2 patches into pvgrub.
	* Add support for PV ops to a version of /boot, and make it usable as
	a kernel in Xen, similar to pvgrub.

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