installing VyOS via rsync(1) for fun and profit

Inspired by Linode’s documentation of the general case of installing a custom Linux distribution on a remote machine that can’t boot from an arbitrary ISO image.

You’ll need:

a staging machine: either a physical box that can boot from a VyOS live CD or a virtual machine that can boot from an ISO image of one;
a target machine on which you ultimately want to run VyOS;
a disk of at least 1 GB (2 GB recommended) on each machine;
console access to both machines;
the ability to establish a network connection between them; and
the ability to boot the target machine from a rescue CD, such as Finnix.

Boot the staging machine from the VyOS live CD. (Don’t take the shortcut of using VyOS’s OVA template.)
Install VyOS:
```
 vyos@vyos:~$ install system
```
Boot the remote machine from the Finnix live CD.

Create /dev/xvda1 (or equivalent) to match the staging machine’s /dev/sda1 (or equivalent):

 root@hvc0:~# parted /dev/xvda mklabel msdos
 root@hvc0:~# parted /dev/xvda mkpart primary "0%" "100%"
 root@hvc0:~# parted /dev/xvda set 1 boot on

Confirm your changes:
```
 root@hvc0:~# parted /dev/xvda print
```
Give the new partition a filesystem:
```
 root@hvc0:~# mkfs.ext4 /dev/xvda1
```
Mount it:
```
 root@hvc0:~# mount /dev/xvda1 /mnt
```

Enable SSH:

 root@hvc0:~# passwd
 root@hvc0:~# vi /etc/ssh/sshd_config
 # Type: :%s/^PermitRootLogin without-password/PermitRootLogin yes/g<Enter>
 root@hvc0:~# service ssh start

On the staging machine, copy the root filesystem to the target machine’s new partition (substituting the latter’s IP address, of course):
```
 vyos@vyos:~$ sudo -i
 root@vyos:~# mount /dev/sda1 /mnt/rootfs
 root@vyos:~# rsync -ahz --stats /mnt/rootfs/ root@192.0.2.253:/mnt/
```

On the target machine, update the filesystem table:

root@hvc0:~# blkid
root@hvc0:~# vi /mnt/etc/fstab
# Replace given UUID with that returned for /dev/xvda1.

Follow Finnix’s instructions for reconfiguring GRUB:

root@hvc0:~# mount -t proc none /mnt/proc
root@hvc0:~# mount -t sysfs none /mnt/sys
root@hvc0:~# mount --bind /dev /mnt/dev
root@hvc0:~# chroot /mnt
root@finnix:/# cat /proc/mounts > /etc/mtab
root@finnix:/# vi /etc/mtab
# Remove all lines before "/dev/xvda1".
root@finnix:/# /opt/vyatta/sbin/vyatta-grub-setup xvda1
root@finnix:/# grub-install /dev/xvda

Back out:

root@finnix:/# exit
root@hvc0:~# umount /mnt/dev
root@hvc0:~# umount /mnt/sys
root@hvc0:~# umount /mnt/proc
root@hvc0:~# umount /mnt

Reboot the target machine. Depending on your console, you may not see the usual GRUB menu, but if you type <Enter> you should see the VyOS login prompt:
```
Welcome to VyOS - vyos ttyS0

vyos login: 
```