How to use remote assistance with Ubuntu Frame

Contents:

• The ubuntu-frame-vnc snap
  • Using as a daemon
  • Running manually
• Remote access
• Client compatibility
• Debugging

This document describes how to use the remote assistance function in Ubuntu Frame.

The ubuntu-frame-vnc snap

The remote assistance feature of Ubuntu Frame is provided by the ubuntu-frame-vnc snap. This needs to run on the same device as Ubuntu Frame and, under the hood, it uses wayvnc built and configured to work with Ubuntu Frame.

You can install the snap:

$ snap install ubuntu-frame-vnc

Using as a daemon

The default on Ubuntu Core, using as a daemon allows you to always have the remote access enabled. To turn the daemon feature on or off, use:

$ sudo snap set ubuntu-frame-vnc daemon=true
# or
$ sudo snap set ubuntu-frame-vnc daemon=false

Running manually

To run the server manually, just issue:

$ ubuntu-frame-vnc
# Ctrl+C to stop

NB: If you’re running Frame on a Wayland desktop, by default this will try and connect to your desktop rather than Frame. On Ubuntu 22.04, for example, the symptom is:

$ ubuntu-frame-vnc 
wl_registry@2: error 0: invalid version for global wl_output (5): have 2, wanted 3
ERROR: Compositor doesn't support screencopy! Exiting.
ERROR: Failed to initialise wayland

To make sure you’re using the same WAYLAND_DISPLAY, run all the components with the same value of the variable:

$ WAYLAND_DISPLAY=wayland-99 ubuntu-frame
# in another terminal
$ WAYLAND_DISPLAY=wayland-99 ubuntu-frame-vnc

Remote access

Rather than expose an extra attack surface, ubuntu-frame-vnc is configured to only listen on localhost, on port 5900 (the default VNC port). It is up to the operator to expose it securely to the outside or provide other means of access.

SSH port forwarding is a common approach: Here is one example using the frame-it snap and gvncviewer:

$ sudo snap install frame-it
$ sudo apt install gvncviewer
...
$ frame-it.vnc <user>@<hostname>

Client compatibility

The following VNC client software was tested against this:

• Remmina
• TigerVNC
• RealVNC
• gtk-vnc
• not working: Finder on macOS (any1/neatvnc#48)

Debugging

When things don’t work as expected, the general rules apply when debugging snaps.

The first place to look would be snap logs ubuntu-frame-vnc. Use -n <number> to see more history.

You can also use [sudo] snap run --shell ubuntu-frame-vnc to get into the environment of the VNC server and poke around. Use ${SNAP}/usr/local/bin/wayvnc to run it, and provide configuration options, like --log-level trace to get more information.

Please file any issues you find, with as much context as possible, on the GitHub page.