Installing FreeBSD on older dedicated servers via the Linux rescue system

Introduction

Hetzner no longer offers a FreeBSD rescue system. For dedicated servers with full UEFI support there is a tutorial showing how to install FreeBSD with OpenZFS from the Linux rescue system: Installing FreeBSD with OpenZFS via the Linux rescue system

For older servers that only have minimal UEFI support and require legacy BIOS boot, there is a different way to install FreeBSD.

Prerequisites:

• Hetzner dedicated server booted in Linux rescue mode with working SSH access
• IPv6 network configuration parameters:
  • IPv6 address assigned

Optional:

• IPv4 network configuration parameters:
  • IP address and network length
  • Default gateway

Note: Dedicated servers without an IPv4 address must be configured correctly since DHCP and autodetect does not work.

Example terminology

• IPv4: 192.168.0.2/27
• IPv4 Gateway: 192.168.0.1
• IPv6: 2a01:4f8:0:0::2/64
• NIC: Intel(R) PRO/1000 Network Driver
• Drive 1: /dev/nvme0n1
• Drive 2: /dev/nvme1n1

Use /dev/sda and /dev/sdb on systems with SATA drives.

We will install FreeBSD 14.0-RELEASE in our example.

Step 1 - Download the FreeBSD distribution archives

Download base.txz and kernel.txz from a FreeBSD mirror:

curl -O http://ftp2.de.freebsd.org/pub/FreeBSD/releases/amd64/14.0-RELEASE/base.txz
curl -O http://ftp2.de.freebsd.org/pub/FreeBSD/releases/amd64/14.0-RELEASE/kernel.txz

Step 2 - Download the mfsBSD installation VM container

We use mfsBSD virtual machine to install FreeBSD on the system drives.

Download the ISO image:

curl -O https://mfsbsd.vx.sk/files/iso/14/amd64/mfsbsd-14.0-RELEASE-amd64.iso

Step 3 - Launch the mfsBSD virtual machine from the ISO image

The server disks are passed through to the VM as SCSI devices using virtio.

In the command below, replace /dev/nvme0n1 and /dev/nvme1n1 as needed.

qemu-system-x86_64 -net nic -net user,hostfwd=tcp::1022-:22 -m 2048M -enable-kvm \
 -cpu host,+nx -M pc -smp 2 -vga std -k en-us \
 -cdrom ./mfsbsd-14.0-RELEASE-amd64.iso \
 -device virtio-scsi-pci,id=scsi0 \
 -drive file=/dev/nvme0n1,if=none,format=raw,discard=unmap,aio=native,cache=none,id=n0 \
 -device scsi-hd,drive=n0,bus=scsi0.0 \
 -drive file=/dev/nvme1n1,if=none,format=raw,discard=unmap,aio=native,cache=none,id=n1 \
 -device scsi-hd,drive=n1,bus=scsi0.0 \
 -boot once=d -vnc 127.0.0.1:0,password=on -monitor stdio

The SSH service inside the VM is made available on port 1022 of the rescue system.

Note:
The disk devices of the servers will be attached as SCSI disks in the VM no matter what they are on the host. This means that inside the VM the disks are always mapped to /dev/da0 and /dev/da1.

Set a VNC password to allow VNC access (Optional)

You need to forward port 5900 using SSH to connect to VNC!

(qemu) set_password vnc mfsroot
(qemu) 

Step 4 - Copy the distribution files to the VM

On a root shell of the rescue Linux system, run the following command:

scp -o Port=1022 base.txz kernel.txz root@localhost:

The root password inside the virtual machine is mfsroot.

Step 5 - Login to the VM

Use SSH to log into the VM from a shell on the rescue system:

ssh -p 1022 root@localhost

The password is mfsroot.

Verify that the drives are visible:

dmesg | grep QEMU
cd0: <QEMU QEMU DVD-ROM 2.5+> Removable CD-ROM SCSI device
da0: <QEMU QEMU HARDDISK 2.5+> Fixed Direct Access SPC-3 SCSI device
da1: <QEMU QEMU HARDDISK 2.5+> Fixed Direct Access SPC-3 SCSI device

Step 6 - Install FreeBSD

Install FreeBSD with the zfsinstall script:

zfsinstall -d /dev/da0 -d /dev/da1 -r mirror -p zroot -s 16G -u .

This will install FreeBSD on a ZFS pool zroot using RAID-1 (mirror) on both disks with 16GiByte swap space on each disk.

The installed FreeBSD root filesystem will be mounted on /mnt. Since we are running the current version of FreeBSD inside the VM, we can now already just use chroot to configure the new installation:

mount -t devfs devfs /mnt/dev
chroot /mnt

Step 7 - Configure FreeBSD

Once we used chroot to get a shell running inside the installed FreeBSD environment, we can complete the configuration.

• Set a root password

  passwd

• Enable root login with password

  echo "PermitRootLogin yes" >> /etc/ssh/sshd_config
  echo "PasswordAuthentication yes" >> /etc/ssh/sshd_config

  Note: You may want to disable this later after you created user accounts

• Set the hostname, and enable sshd & our newly created autodhcpd script

  Create the file /etc/rc.conf with the following content:

  cat << EOF > /etc/rc.conf
  zfs_enable="YES"
  hostname="myhost.mydomain"
  sshd_enable="YES"
  EOF

Step 8 - Configure the network settings

If your server uses a RealTec based network card, the name of your interface is most likely re0.
If your server uses an Intel based network card, the name is either em0 or igb0.
If in doubt, use Google to find out what your NIC would be called in FreeBSD.

In our example we need to use em0 as the name of our network card.

Add the following lines to the /etc/rc.conf file:

In the command below, replace em0, 192.168.0.2/27, 192.168.0.1, and 2a01:4f8:0:0::2/64 as needed.

cat <<EOF >>/etc/rc.conf
ifconfig_em0="192.168.0.2/27"
static_routes="gateway default"
route_gateway="-host 192.168.0.1 -interface em0"
route_default="default 192.168.0.1"
ifconfig_em0_ipv6="inet6 2a01:4f8:0:0::2/64"
ipv6_defaultrouter="fe80::1%em0"
EOF

Step 9 - Clean up

Exit the chroot environment and unmount the filesystems

exit
sync
umount /mnt/dev
umount /mnt/var
umount /mnt/tmp
umount /mnt

You can either shut down the qemu virtual machine or terminate the qemu process.

With everything set up, you can reboot the server into the FreeBSD distribution:

reboot

Conclusion

Congratulations! You now have a working FreeBSD installation that does not require full UEFI support.

Additional note:

If your installation gets broken and doesn't boot anymore, you can use the Linux rescue system to access it:

License: MIT