FreeBSD Handbook
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21.2 FreeBSD as a Guest OS

21.2.1 Parallels on MacOS

Parallels Desktop for Mac® is a commercial software product available for Intel® based Apple® Mac computers running Mac OS® 10.4.6 or higher. FreeBSD is a fully supported guest operating system. Once Parallels has been installed on Mac OS X, the user must configure a virtual machine and then install the desired guest operating system.

21.2.1.1 Installing FreeBSD on Parallels/Mac OS® X

The first step in installing FreeBSD on Mac OS X/Parallels is to create a new virtual machine for installing FreeBSD. Select FreeBSD as the Guest OS Type when prompted:

And choose a reasonable amount of disk and memory depending on your plans for this virtual FreeBSD instance. 4GB and 512MB of RAM work well for most uses of FreeBSD under Parallels:

Select the type of networking and a network interface:

Save and finish the configuration:

After your FreeBSD virtual machine has been created, you will need to install FreeBSD on it. This is best done with an official FreeBSD CDROM or with an ISO image downloaded from an official FTP site. When you have the appropriate ISO image on your local Mac filesystem or a CDROM in your Mac's CD drive, click on the disc icon in the bottom right corner of your FreeBSD Parallels window. This will bring up a window that allows you to associate the CDROM drive in your virtual machine with an ISO file on disk or with your real CDROM drive.

Once you have made this association with your CDROM source, reboot your FreeBSD virtual machine as normal by clicking the reboot icon. Parallels will reboot with a special BIOS that first checks if you have a CDROM just as a normal BIOS would do.

In this case it will find the FreeBSD installation media and begin a normal sysinstall based installation as described in Chapter 2. You may install, but do not attempt to configure X11 at this time.

When you have finished the installation, reboot into your newly installed FreeBSD virtual machine.

21.2.1.2 Configuring FreeBSD on Mac OS X/Parallels

After FreeBSD has been successfully installed on Mac OS X with Parallels, there are a number of configuration steps that can be taken to optimize the system for virtualized operation.

Set boot loader variables

The most important step is to reduce the kern.hz tunable to reduce the CPU utilization of FreeBSD under the Parallels environment. This is accomplished by adding the following line to /boot/loader.conf:
```
kern.hz=100
```
Without this setting, an idle FreeBSD Parallels guest OS will use roughly 15% of the CPU of a single processor iMac®. After this change the usage will be closer to a mere 5%.
Create a new kernel configuration file

You can remove all of the SCSI, FireWire, and USB device drivers. Parallels provides a virtual network adapter used by the ed(4) driver, so all other network devices except for ed(4) and miibus(4) can be removed from the kernel.
Setup networking

The most basic networking setup involves simply using DHCP to connect your virtual machine to the same local area network as your host Mac. This can be accomplished by adding ifconfig_ed0="DHCP" to /etc/rc.conf. More advanced networking setups are described in Chapter 29.

21.2.2 FreeBSD with Xen™ on Linux

Contributed by Fukang Chen (Loader).

The Xen™ hypervisor is an open source paravirtualization product which is now supported by the commercial XenSource company. Guest operating systems are known as domU domains, and the host operating system is known as dom0. The first step in running a virtual FreeBSD instance under Linux is to install Xen for Linux dom0. The host operating system will be a Slackware Linux distribution.

21.2.2.1 Setup Xen 3 on Linux dom0

Download Xen 3.0 from XenSource

Download xen-3.0.4_1-src.tgz from http://www.xensource.com/.

Unpack the tarball

# cd xen-3.0.4_1-src
# KERNELS="linux-2.6-xen0 linux-2.6-xenU" make world
# make install

Note: To re-compile the kernel for dom0:
# cd xen-3.0.4_1-src/linux-2.6.16.33-xen0
# make menuconfig
# make
# make install
Older version of Xen may need to specify make ARCH=xen menuconfig

Add a menu entry into Grub menu.lst

Edit /boot/grub/menu.lst and add the following lines:

title Xen-3.0.4
root (hd0,0)
kernel /boot/xen-3.0.4-1.gz dom0_mem=262144
module /boot/vmlinuz-2.6.16.33-xen0 root=/dev/hda1 ro

Reboot your computer into Xen

First, edit /etc/xen/xend-config.sxp, and add the following line:

(network-script 'network-bridge netdev=eth0')

Then, we can launch Xen:

# /etc/init.d/xend start
# /etc/init.d/xendomains start

Our dom0 is running:

# xm list
Name                                      ID   Mem VCPUs      State   Time(s)
Domain-0                                   0   256     1     r-----  54452.9

21.2.2.2 FreeBSD 7-CURRENT domU

Download the FreeBSD domU kernel for Xen 3.0 and disk image from http://www.fsmware.com/

Put the configuration file xmexample1.bsd into /etc/xen/ and modify the related entries about where the kernel and the disk image are stored. It should look like the following:

kernel = "/opt/kernel-current"
memory = 256
name = "freebsd"
vif = [ '' ]
disk = [ 'file:/opt/mdroot-7.0,hda1,w' ]
#on_crash    = 'preserve'
extra = "boot_verbose"
extra += ",boot_single"
extra += ",kern.hz=100"
extra += ",vfs.root.mountfrom=ufs:/dev/xbd769a"

The mdroot-7.0.bz2 file should be uncompressed.

Next, the __xen_guest section in kernel-current needs to be altered to add the VIRT_BASE that Xen 3.0.3 requires:

# objcopy kernel-current -R __xen_guest
# perl -e 'print "LOADER=generic,GUEST_OS=freebsd,GUEST_VER=7.0,XEN_VER=xen-3.0,BSD_SYMTAB,VIRT_BASE=0xC0000000\x00"' > tmp
# objcopy kernel-current --add-section __xen_guest=tmp

# objdump -j __xen_guest -s kernel-current

kernel-current:     file format elf32-i386

Contents of section __xen_guest:
 0000 4c4f4144 45523d67 656e6572 69632c47  LOADER=generic,G
 0010 55455354 5f4f533d 66726565 6273642c  UEST_OS=freebsd,
 0020 47554553 545f5645 523d372e 302c5845  GUEST_VER=7.0,XE
 0030 4e5f5645 523d7865 6e2d332e 302c4253  N_VER=xen-3.0,BS
 0040 445f5359 4d544142 2c564952 545f4241  D_SYMTAB,VIRT_BA
 0050 53453d30 78433030 30303030 3000      SE=0xC0000000.

We are, now, ready to create and launch our domU:

# xm create /etc/xen/xmexample1.bsd -c
Using config file "/etc/xen/xmexample1.bsd".
Started domain freebsd
WARNING: loader(8) metadata is missing!
Copyright (c) 1992-2006 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
The Regents of the University of California. All rights reserved.
FreeBSD 7.0-CURRENT #113: Wed Jan  4 06:25:43 UTC 2006
    kmacy@freebsd7.gateway.2wire.net:/usr/home/kmacy/p4/freebsd7_xen3/src/sys/i386-xen/compile/XENCONF
WARNING: DIAGNOSTIC option enabled, expect reduced performance.
Xen reported: 1796.927 MHz processor.
Timecounter "ixen" frequency 1796927000 Hz quality 0
CPU: Intel(R) Pentium(R) 4 CPU 1.80GHz (1796.93-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0xf29  Stepping = 9
  Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,
  DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
  Features2=0x4400<CNTX-ID,<b14>>
real memory  = 265244672 (252 MB)
avail memory = 255963136 (244 MB)
xc0: <Xen Console> on motherboard
cpu0 on motherboard
Timecounters tick every 10.000 msec
[XEN] Initialising virtual ethernet driver.
xn0: Ethernet address: 00:16:3e:6b:de:3a
[XEN] 
Trying to mount root from ufs:/dev/xbd769a
WARNING: / was not properly dismounted
Loading configuration files.
No suitable dump device was found.
Entropy harvesting: interrupts ethernet point_to_point kickstart.
Starting file system checks:
/dev/xbd769a: 18859 files, 140370 used, 113473 free (10769 frags, 12838 blocks, 4.2% fragmentation)
Setting hostname: demo.freebsd.org.
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
      inet6 ::1 prefixlen 128 
      inet6 fe80::1%lo0 prefixlen 64 scopeid 0x2 
      inet 127.0.0.1 netmask 0xff000000 
Additional routing options:.
Mounting NFS file systems:.
Starting syslogd.
/etc/rc: WARNING: Dump device does not exist.  Savecore not run.
ELF ldconfig path: /lib /usr/lib /usr/lib/compat /usr/X11R6/lib /usr/local/lib
a.out ldconfig path: /usr/lib/aout /usr/lib/compat/aout /usr/X11R6/lib/aout
Starting usbd.
usb: Kernel module not available: No such file or directory
Starting local daemons:.
Updating motd.
Starting sshd.
Initial i386 initialization:.
Additional ABI support: linux.
Starting cron.
Local package initialization:.
Additional TCP options:.
Starting background file system checks in 60 seconds.

Sun Apr  1 02:11:43 UTC 2007

FreeBSD/i386 (demo.freebsd.org) (xc0)

login:

The domU should run the FreeBSD 7.0-CURRENT kernel:

# uname -a
FreeBSD demo.freebsd.org 7.0-CURRENT FreeBSD 7.0-CURRENT #113: Wed Jan  4 06:25:43 UTC 2006     
kmacy@freebsd7.gateway.2wire.net:/usr/home/kmacy/p4/freebsd7_xen3/src/sys/i386-xen/compile/XENCONF  i386

The network can now be configured on the domU. The FreeBSD domU will use a specific interface called xn0:

# ifconfig xn0 10.10.10.200 netmask 255.0.0.0
# ifconfig
xn0: flags=843<UP,BROADCAST,RUNNING,SIMPLEX> mtu 1500
    inet 10.10.10.200 netmask 0xff000000 broadcast 10.255.255.255
    ether 00:16:3e:6b:de:3a
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
      inet6 ::1 prefixlen 128 
      inet6 fe80::1%lo0 prefixlen 64 scopeid 0x2 
      inet 127.0.0.1 netmask 0xff000000

On dom0 Slackware, some Xen dependant network interfaces should show up:

# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:07:E9:A0:02:C2  
          inet addr:10.10.10.130  Bcast:0.0.0.0  Mask:255.0.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:815 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1400 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:204857 (200.0 KiB)  TX bytes:129915 (126.8 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:99 errors:0 dropped:0 overruns:0 frame:0
          TX packets:99 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:9744 (9.5 KiB)  TX bytes:9744 (9.5 KiB)

peth0     Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF  
          UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1
          RX packets:1853349 errors:0 dropped:0 overruns:0 frame:0
          TX packets:952923 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:2432115831 (2.2 GiB)  TX bytes:86528526 (82.5 MiB)
          Base address:0xc000 Memory:ef020000-ef040000 

vif0.1    Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF  
          UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1
          RX packets:1400 errors:0 dropped:0 overruns:0 frame:0
          TX packets:815 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:129915 (126.8 KiB)  TX bytes:204857 (200.0 KiB)

vif1.0    Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF  
          UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1
          RX packets:3 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2 errors:0 dropped:157 overruns:0 carrier:0
          collisions:0 txqueuelen:1 
          RX bytes:140 (140.0 b)  TX bytes:158 (158.0 b)

xenbr1    Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF  
          UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1
          RX packets:4 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:112 (112.0 b)  TX bytes:0 (0.0 b)

# brctl show
bridge name     bridge id           STP enabled         interfaces
xenbr1          8000.feffffffffff   no                  vif0.1
                                                        peth0
                                                        vif1.0

21.2.3 VMware on Windows®/Mac®/Linux®

This section has yet to be written.