Bhyve is a FreeBSD hypervisor. It first appeared in FreeBSD 10.0. However, it's
recommended to keep tracking FreeBSD 10-STABLE to make sure all new features
of bhyve are supported.
In order to enable bhyve on your FreeBSD host, you'll need to load the vmm
kernel module. Additionally, if_tap and if_bridge modules
should be loaded for networking support.
Additional information on bhyve could be obtained on bhyve.org.
The libvirt bhyve driver is a single-instance privileged driver. Some sample connection URIs are:
bhyve:///system (local access) bhyve+unix:///system (local access) bhyve+ssh://root@example.com/system (remote access, SSH tunnelled)
The bhyve driver in libvirt is in its early stage and under active development. So it supports only limited number of features bhyve provides.
Note: in older libvirt versions, only a single network device and a single disk device were supported per-domain. However, since 1.2.6 the libvirt bhyve driver supports up to 31 PCI devices.
Note: the Bhyve driver in libvirt will boot whichever device is first. If you want to install from CD, put the CD device first. If not, put the root HDD first.
Note: Only the SATA bus is supported. Only cdrom- and
disk-type disks are supported.
<domain type='bhyve'>
<name>bhyve</name>
<uuid>df3be7e7-a104-11e3-aeb0-50e5492bd3dc</uuid>
<memory>219136</memory>
<currentMemory>219136</currentMemory>
<vcpu>1</vcpu>
<os>
<type>hvm</type>
</os>
<features>
<apic/>
<acpi/>
</features>
<clock offset='utc'/>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>destroy</on_crash>
<devices>
<disk type='file'>
<driver name='file' type='raw'/>
<source file='/path/to/bhyve_freebsd.img'/>
<target dev='hda' bus='sata'/>
</disk>
<disk type='file' device='cdrom'>
<driver name='file' type='raw'/>
<source file='/path/to/cdrom.iso'/>
<target dev='hdc' bus='sata'/>
<readonly/>
</disk>
<interface type='bridge'>
<model type='virtio'/>
<source bridge="virbr0"/>
</interface>
</devices>
</domain>
(The <disk> sections may be swapped in order to install from cdrom.iso.)
Note the addition of <bootloader>.
<domain type='bhyve'>
<name>linux_guest</name>
<uuid>df3be7e7-a104-11e3-aeb0-50e5492bd3dc</uuid>
<memory>131072</memory>
<currentMemory>131072</currentMemory>
<vcpu>1</vcpu>
<bootloader>/usr/local/sbin/grub-bhyve</bootloader>
<os>
<type>hvm</type>
</os>
<features>
<apic/>
<acpi/>
</features>
<clock offset='utc'/>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>destroy</on_crash>
<devices>
<disk type='file' device='disk'>
<driver name='file' type='raw'/>
<source file='/path/to/guest_hdd.img'/>
<target dev='hda' bus='sata'/>
</disk>
<disk type='file' device='cdrom'>
<driver name='file' type='raw'/>
<source file='/path/to/cdrom.iso'/>
<target dev='hdc' bus='sata'/>
<readonly/>
</disk>
<interface type='bridge'>
<model type='virtio'/>
<source bridge="virbr0"/>
</interface>
</devices>
</domain>
Guest console connection is supported through the nmdm device. It could be enabled by adding
the following to the domain XML (Since 1.2.4):
...
<devices>
<serial type="nmdm">
<source master="/dev/nmdm0A" slave="/dev/nmdm0B"/>
</serial>
</devices>
...
Make sure to load the nmdm kernel module if you plan to use that.
Then virsh console command can be used to connect to the text console
of a guest.
NB: Some versions of bhyve have a bug that prevents guests from booting
until the console is opened by a client. This bug was fixed in FreeBSD
r262884. If
an older version is used, one either has to open a console manually with virsh console
to let a guest boot or start a guest using:
start --console domname
NB: An bootloader configured to require user interaction will prevent
the domain from starting (and thus virsh console or start
--console from functioning) until the user interacts with it manually on
the VM host. Because users typically do not have access to the VM host,
interactive bootloaders are unsupported by libvirt. However, if you happen to
run into this scenario and also happen to have access to the Bhyve host
machine, you may select a boot option and allow the domain to finish starting
by using an alternative terminal client on the VM host to connect to the
domain-configured null modem device. One example (assuming
/dev/nmdm0B is configured as the slave end of the domain serial
device) is:
cu -l /dev/nmdm0B
The virsh domxml-to-native command can preview the actual
bhyve commands that will be executed for a given domain.
It outputs two lines, the first line is a bhyveload command and
the second is a bhyve command.
Please note that the virsh domxml-to-native doesn't do any
real actions other than printing the command, for example, it doesn't try to
find a proper TAP interface and create it, like what is done when starting
a domain; and always returns tap0 for the network interface. So
if you're going to run these commands manually, most likely you might want to
tweak them.
# virsh -c "bhyve:///system" domxml-to-native --format bhyve-argv --xml /path/to/bhyve.xml /usr/sbin/bhyveload -m 214 -d /home/user/vm1.img vm1 /usr/sbin/bhyve -c 2 -m 214 -A -I -H -P -s 0:0,hostbridge -s 3:0,virtio-net,tap0,mac=52:54:00:5d:74:e3 -s 2:0,virtio-blk,/home/user/vm1.img -s 1,lpc -l com1,/dev/nmdm0A vm1
It's possible to use ZFS volumes as disk devices since 1.2.8. An example of domain XML device entry for that will look like:
...
<disk type='volume' device='disk'>
<source pool='zfspool' volume='vol1'/>
<target dev='vdb' bus='virtio'/>
</disk>
...
Please refer to the Storage documentation for more details on storage management.
It's possible to boot non-FreeBSD guests by specifying an explicit
bootloader, e.g. grub-bhyve(1). Arguments to the bootloader may be
specified as well. If the bootloader is grub-bhyve and arguments
are omitted, libvirt will try and infer boot ordering from user-supplied
<boot order='N'> configuration in the domain. Failing that, it will boot
the first disk in the domain (either cdrom- or
disk-type devices). If the disk type is disk, it will
attempt to boot from the first partition in the disk image.
...
<bootloader>/usr/local/sbin/grub-bhyve</bootloader>
<bootloader_args>...</bootloader_args>
...
Caveat: bootloader_args does not support any quoting.
Filenames, etc, must not have spaces or they will be tokenized incorrectly.
Originally bhyve supported only localtime for RTC. Support for UTC time was introduced in r284894 for 10-STABLE and in r279225 for -CURRENT. It's possible to use this in libvirt since 1.2.18, just place the following to domain XML:
<domain type="bhyve">
...
<clock offset='utc'/>
...
</domain>
Please note that if you run the older bhyve version that doesn't support UTC time, you'll fail to start a domain. As UTC is used as a default when you do not specify clock settings, you'll need to explicitly specify 'localtime' in this case:
<domain type="bhyve">
...
<clock offset='localtime'/>
...
</domain>