Files
tailscale/gokrazy
Brad FitzpatrickandBrad Fitzpatrick 4c22d22df5 cmd/fbstatus: add framebuffer status display for the Tailscale appliance
Adds a Linux-only framebuffer status display (cmd/fbstatus) that draws
to /dev/fb0 on the Tailscale gokrazy appliance. It shows:

  - the Tailscale logo
  - the current tailscaled state (starting, needs login, running)
  - a QR code with the login URL when enrollment is needed (triggers
    StartLoginInteractive automatically so the URL appears without
    user action)
  - the LAN IP or "Waiting for DHCP (MAC)" pinned at the bottom-left
  - Tailscale IPs once connected

VT switching: Ctrl-Alt-F2 drops to a busybox text shell on VT2 (for
debugging with a USB keyboard), Ctrl-Alt-F1 returns to the GUI.
Rendering pauses while the text VT is active.

On boot, fbstatus pokes the gokrazy unix socket API to restart the
breakglass SSH service (which uses DontStartOnBoot by default). It
waits until DHCP assigns an IP so breakglass binds to the LAN address
rather than just localhost.

Included in the tsapp-pi.arm64 gokrazy build by default.

Updates #1866

Change-Id: Ifdce4ad8e8c2e1005c840f579e637974a0a266d3
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2026-07-02 09:24:01 -07:00
..

Tailscale Appliance Gokrazy Image

This is (as of 2024-06-02) a WORK IN PROGRESS (pre-alpha) experiment to package Tailscale as a Gokrazy appliance image for use on both VMs (AWS, GCP, Azure, Proxmox, ...) and Rasperry Pis.

See https://github.com/tailscale/tailscale/issues/1866

Overview

It makes a ~70MB image (about the same size as tailscale-setup-full-1.66.4.exe and smaller than the combined Tailscale Android APK) that combines the Linux kernel and Tailscale and that's it. Nothing written in C. (except optional busybox for debugging) So no operating system to maintain. Gokrazy has three partitions: two read-only ones (one active at a time, the other for updates for the next boot) and one optional stateful, writable partition that survives upgrades (/perm/)

Initial bootstrap configuration of this appliance will be over either serial or configuration files (auth keys, subnet routes, etc) baked into the image (for Raspberry Pis) or in cloud-init/user-data (for AWS, etc). As of 2024-06-02, AWS user-data config files work.

Quick start

Install dependencies:

$ brew install qemu e2fsprogs

Build + launch:

$ make qemu

That puts serial on stdio. To exit the serial console and escape to the qemu monitor, type Ctrl-a c. Then type quit in the monitor to quit.

Building

make image to build just the image (tsapp.img), without uploading it.

UTM

You can also use UTM, but the qemu path above is easier. For UTM, see the UTM instructions.

AWS

Build an AMI

go run build.go --bucket=your-S3-temp-bucket to build an AMI. Make sure your "aws" command is in your path and has access.

Creating an instance

When creating an instance, you need a Nitro machine type to get a virtual serial console. Notably, that means the t2.* instance types that AWS pushes as a free option are not new enough. Use t3.* at least.

As of 2024-06-02 this builder tool only supports x86_64 (arm64 should be trivial and will come soon), so don't use a Graviton machine type.

To connect to the serial console, you can either use the web console, or use the CLI like:

$ aws ec2-instance-connect send-serial-console-ssh-public-key --instance-id i-0b4a0eabc43629f13 --serial-port 0 --ssh-public-key file:///your/home/.ssh/id_ed25519.pub --region us-west-2
{
    "RequestId": "a93b0ea3-9ff9-45d5-b8ed-b1e70ccc0410",
    "Success": true
}
$ ssh i-0b4a0eabc43629f13.port0@serial-console.ec2-instance-connect.us-west-2.aws