This post gives brief details on how to user LXD to run multiple ROS/ROS2 versions in a Ubuntu machine.

LXD is a next generation system container and virtual machine manager. It offers a unified user experience around full Linux systems running inside containers or virtual machines.

In my use case I am running ROS2 Humble in my LXD-host machine (Ubuntu 22.04). I want to run ROS2 Foxy (needs Ubuntu 20.04) in a LXD container in order to use realsense-ros package.

Install LXD

snap install lxd

First time configuration

lxd init # defaults are fine

Launch the desired Ubuntu version

lxc launch ubuntu:20.04 ros-foxy

Run a login shell as the default ubuntu user:

lxc exec ros-foxy -- sudo -iu ubuntu bash

Do a sudo apt update

If the packages fail to download and you get a bunch of "W: Failed to fetch ..." warnings, there is no internet access inside the container.

If you have Docker installed, then most probably the docker daemon is causing this problem.

Yep, it is. Docker made your default FORWARD policy to be DROP which will eat all traffic that’s not meant for Docker itself…

iptables -P FORWARD ACCEPT should temporarily fix that

So run: iptables -P FORWARD ACCEPT to fix this issue and try doing a sudo apt update.

Run RViz and other GUI applications

1. lxc profile create gui Note your display variable by running echo $DISPLAY in your terminal. My terminal returned :1.
2. lxc profile edit gui Paste the following config and change the display variable (in places where "#change here" is mentioned):

config:
  environment.DISPLAY: :1 #change here
  raw.idmap: both 1000 1000
  user.user-data: |
    #cloud-config
    runcmd:
      - 'sed -i "s/; enable-shm = yes/enable-shm = no/g" /etc/pulse/client.conf'
      - 'echo export PULSE_SERVER=unix:/tmp/.pulse-native | tee --append /home/ubuntu/.profile'
    packages:
      - x11-apps
      - mesa-utils
      - pulseaudio
description: GUI LXD profile
devices:
  PASocket:
    path: /tmp/.pulse-native
    source: /run/user/1000/pulse/native
    type: disk
  X0:
    path: /tmp/.X11-unix/X1 #change here
    source: /tmp/.X11-unix/X1 # change here
    type: disk
  mygpu:
    type: gpu
name: gui
used_by:

Apply this profile to the existing container and restart using:

lxc profile add ros-foxy gui
lxc restart ros-foxy

Launch the ros-foxy container and lxc exec into it using lxc exec ros-foxy -- sudo -iu ubuntu bash. Now all the GUI will be X11 forwarded.

Unsupported version 0 of Verneed record

If this error shows up when trying to lxc exec, try restarting your device. This should temporarily fix it. More information can be found here.

References

ROS Development with LXD
No internet access inside container but container is able to ping to host