VyOS on an Asus Chromebox M004U

Networks, Unixy

This is a bit of a follow up from my last post. I’ve still got my Asus Chromebox. I’m not running ESXi any more… but something I do want to try out is VyOS. Why? Well, my original intent when purchasing the Chromebox was to play around with it, but then I really did expect it to replace my home router. I’ve used pfSense for a long time, but I’m curious about VyOS because I know several people using EdgeRouter Lite which uses EdgeOS, a fork of VyOS. So I wanted to play around on existing hardware.

Note: everything below assumes your Chromebox has custom firmware for installing any OS you choose (see last post).

Turns out though, VyOS isn’t quite ready for installing on UEFI systems. And the Chromebox is… well… sort of UEFI, even though it uses SeaBIOS. Also, while most UEFI systems have a management screen where you can configure legacy mode, the Chromebox is a bit more limited in how we can work around its oddities.

Bottom line, VyOS installer would not boot directly on the Chromebox. I wasn’t thinking “UEFI is the problem” when I first hit the boot issue; I assumed it was an issue with USB 3. After much poking and prodding, I was able to get it running. But it was tricky enough, I figured I should document the process.

Install VyOS

First things first, you’ll need another system, a BIOS system, on which you can install VyOS. This doesn’t have to be a physical computer. VyOS is very often used in virtualized environments. In my case, all initial testing was done on a physical BIOS machine, but for proving out a second round of tests, and to aid in documentation for this blog, I did another install using a VMware machine for my starting system.

I used both the 1.1.7 stable and 1.2.0-beta1 releases for my testing, but always 64-bit ISO installations. I didn’t use any pre-made images.

Using VMware (etc), it’s super easy to install. I used a VM with 1GB of RAM and 10GB of hard disk. I removed most extra devices, as we don’t need them, but I did keep the USB controller. Note: 10GB hard drive was chosen to be sure it is smaller than the 16GB SSD in the Chromebox; it may not matter in the long run but makes me feel safer.

Once you have a VM created, and the ISO downloaded, boot and follow the VyOS install guide.

Quick summary:

  1. boot
  2. login as vyos
  3. run install image
  4. use default config
  5. set password for vyos user to something
  6. auto partition disk sda using whole 10GB of disk
  7. install grub to sda
  8. DONE

Reboot to make sure it boots. Huzzah!

SystemRescueCD

We aren’t going to clone in a traditional sense, no Ghost or Clonezilla… nope. We’re just going to take the bits we need. First, we need a rescue disk to boot from. I’m a long time fan of SystemRescueCD as it has lots and lots of useful tools, can cache itself 100% into RAM, and has a decent X Windows setup available if you need it.

So, download the latest ISO of SystemRescueCD. Before we go any further, make a bootable USB thumb drive from this. The easiest way is to be running Linux already, mount the ISO image, and run the usb_inst.sh script. On Windows you can try using Rufus, which I use when on Windows. On OSX, well… dd might work.

OK, set the SystemRescueUSB aside for now…

Copy the Disk

Now we are ready to clone the disk. Configure the ISO image as your bootable drive in your VyOS VM, then boot it up. You may need to be quick on the “ESC” key to get into the boot menu. The default SystemRescueCD boot option should be fine.

Once you are sitting at a shell prompt, insert that SystemRescueUSB drive you made. You’ll want to make sure it’s connected to the VM, not your host system.

It’s connected, so mount it up, and create a place to store our VyOS stuff

Now, copy out the MBR, which holds both the partition table and the bootloader.

Sweet… now make a copy of the filesystem.

Excellent! sync for good measure, then unmount and remove the USB drive.

Paste the Disk

ALERT: NEXT STEP WILL ERASE EVERYTHING ON YOUR CHROMEBOX SSD!

Lay down our copy of the VM filesystem.

So far this has been pretty simple way to copy any Linux file system and partition map. Now its time to do the magic required to get this to boot on the Chromebox.

If you were to reboot right now, you’d get a lovely grub rescue> console, and you wouldn’t be able to boot VyOS.

Convert to GPT Magic

First, unmount that disk again, so we are able to work with it.

Use gdisk to write GPT version of the MBR data we currently have. Choose “1” to use MBR as authoritative ( you MAY not be asked this ), then “w” to write the new GPT data.

Now we need to add an ESP (EFI System Partition) and BIOS compatibility boot/grub partition.

This shows us where we can start adding partitions, 10239MiB. So we add to next mega byte location the ESP, then one more for our BIOS boot part.

Install Grub

Now we need to unsquash the filesystem image used by VyOS so we can re-install the right version of grub.

Let’s bind some system dirs and install grub (the version from VyOS, not SystemRescueCD)!

PHEW! That wasn’t so hard, was it? 🙂

Let’s cleanup the mounts, reboot, and see what happens.

SUCCESS!

Don’t forget you’ll need to remove the USB drive before rebooting.

When booting the Chromebox I now get a VyOS boot and login.