Get a machine

Get a ready made virtual machine image

Run the machine

following change the bios part

qemu-system-x86_64 -m 4096 -smp 4 -serial mon:stdio -nographic -drive file=FreeBSD-14.0-RELEASE-amd64.qcow2 -enable-kvm

Close the machine from within freebsd

poweroff

Download say FreeBSD-15.0-RELEASE-amd64-BASIC-CLOUDINIT-ufs.qcow2.xz

Get a machine

cp FreeBSD-15.0-RELEASE-amd64-BASIC-CLOUDINIT-ufs.qcow2.xz vm00.qcow2.xz

Make a copy of the file to avoid future downloads

uzxz vm00.qcow2.zx

Expand the image

qemu-img resize vm00.qcow2 +4G

Resize the hard disk of the work copy to a desired size in our case increase by 4G

 /usr/bin/qemu-system-x86_64 \
	-enable-kvm -m 8192  -cpu host -smp 4 \
	-drive file=./vm00.qcow2 \
	-monitor unix:/run/vm00.sock,server,nowait \
	-nic tap,mac=b4:e1:ad:2b:d3:00 \
	-serial mon:stdio  -nographic \
	-pidfile /run/user/1001/vm00.pid \
	-name vm00,process=vm00

run the machine with access to serial console. For this FreeBSD image some scripts will be run for you on the virtual machine. Subsequently the virtual machine will reboot and you will be greeted with a login for a root user. Just type root to access FreeBSD are root. From within the root console of the virtual machine get some things ready, such as remote access

passwd

set a root password and reboot the virtual machine

vi /etc/rc.config

set the hostname to a meaningful name

vi /etc/ssh/sshd_config

modify sshd to allow root login

reboot

after setting up a root password reboot the machine. Send your public key file to the guest with ssh-copy-id root@192.168.1.XXX or ssh-copy-id root@guest_hostname where guest_hostname resolves to the ip address of the guest. You should be able to log in the guest with ssh root@192.168.1.XXX or ssh root@guest_hostname. Log in with your new root password either from the serial console or remotely.

vi /etc/ssh/sshd_config

modify sshd to allow root login but only with public key authentication.

service sshd restart

make sure the sshd daemon uses the new configuration - there are alternative ways to do it of course

perform any tasks you want on your virtual machine that runs FreeBSD. One good idea would be to add a new user with wheel privileges instead of using root login. Install any software that you need

pkg update

It is a good idea to add the various ports for easier installation of software. Be where of pkg update issue

After creating the guest virtual machine at one point your drive may be full in which case you may need to increase the drive space (Ram and the like are changes to qemu-system-x86_64) options. From the host do

echo system_powerdown | socat - unix-connect:/path/to/work.sock

stop the virtual machine

qemu-img resize work.qcow2 +4G

expand the drive with the desired amount

qemu-system-x86_64 -drive file=work.qcow2

start the virtual machine. Include all options that you regularly use

ssh root@work

access the root console in the guest

gpart show

see the names of the dist as viewed by gpart. In my case ada0

gpart recover ada0

if there is a corruption fix it (possible after expanding the disk with qemu-img

gpart resize -i 5 ada0

here -i 5 points to (the last) partition of the disk where the root partition is stored

df -h

Check where root partition is mounted on /dev mine was different from /dev/ada0p5. It was on /dev/gpt/rootfs

growfs /dev/gpt/rootfs

grow the partition (this is assuming you used ufs type filesystem)

reboot

reboot and log on again to verify the changes