Create interfaces в rc.conf.

# vi /etc/rc.conf

cloned_interfaces="bridge0 tap1"
ifconfig_bridge0="addm tap1 addm re0 up"

Add modules.

# vi /boot/loader.conf

vmm_load="YES"
if_bridge_load="YES"
if_tap_load="YES"

Add autostart tap interface.

# echo 'net.link.tap.up_on_open=1' >> /etc/sysctl.conf

Reboot server.

# reboot

Create folder for iso-images.

# mkdir -p /vm/iso

Create folder for virtual machine.

# mkdir /vm/f2o

Go to this folder and create VM image.

# truncate -s 8G f2o.img

Start installation FreeBSD.

# /usr/share/examples/bhyve/vmrun.sh -c 1 -m 256M -t tap1 -d f2o.img -i -I /vm/iso/FreeBSD-install-disk.iso f2o

After installation poweroff VM and boot without iso-image.

# /usr/share/examples/bhyve/vmrun.sh -c 1 -m 256M -t tap1 -d f2o.img f2o