Linux

elementary OS Daily in LXD Container

How to run elementary OS Daily from within an LXD Container for elementary OS Desktop development.

Table of Contents

Install LXD

Fire up a Terminal to install and initialize LXD:

sudo apt install lxd
sudo lxd init            # use default values for everything

Add support for GUI applications to LXD

Map the User ID of the host to the container

Run the following on the host (only once). The command appends a new entry in both the /etc/subuid and /etc/subgid subordinate UID/GID files. It allows the LXD service (that runs as root) to remap our user’s ID ($UID, from the host) as requested.

echo "root:$UID:1" | sudo tee -a /etc/subuid /etc/subgid

Create the gui LXD profile

FIrst off we create a new profile called gui with the following command:

sudo lxc profile create gui

Then we make sure it is configured correctly by executing the following command:

cat << EOF | sudo lxc profile edit gui
config:
  environment.DISPLAY: :0
  raw.idmap: both $UID $UID
  user.user-data: |
    #cloud-config
    runcmd:
      - 'sed -i "s/; enable-shm = yes/enable-shm = no/g" /etc/pulse/client.conf'
      - 'echo export PULSE_SERVER=unix:/tmp/.pulse-native | tee --append /home/ubuntu/.profile'
    packages:
      - x11-apps
      - mesa-utils
      - pulseaudio
description: GUI LXD profile
devices:
  PASocket:
    path: /tmp/.pulse-native
    source: /run/user/$UID/pulse/native
    type: disk
  X0:
    path: /tmp/.X11-unix/X0
    source: /tmp/.X11-unix/X0
    type: disk
  mygpu:
    type: gpu
name: gui
used_by:
EOF

Check everything went fine:

sudo lxc profile show gui

Allow containers to use the :0 display

We need to allow containers to use the :0 display of the host machine. In order to do so, add the following custom command in System Settings > Applications > Startup:

xhost +local:

Setup daily container

Create a new container named daily which is based on Ubuntu LTS 18.04 and assign the default and gui profiles to it:

$ sudo lxc launch --profile default --profile gui ubuntu:18.04 daily
Creating daily
Starting daily

Rename User

Although this step is completely optional, it is highly recommended because it ensures we’ll get a nicely named prompt which avoids potential confusion if you deal with multiple containers.

In a nutshell we rename the existing ubuntu user to elementary. For this, we need to jump into the newly created daily container in order to ensure the ubuntu user gets created:

$ sudo lxc exec daily -- sudo --user ubuntu --login
To run a command as administrator (user "root"), use "sudo <command>".
See "man sudo_root" for details.

ubuntu@daily:~$ exit

First enable sudo for elementary

$ sudo lxc exec daily -- sudo --user root --login
mesg: ttyname failed: No such device
root@daily:~# echo "elementary ALL=(ALL) NOPASSWD:ALL" >> /etc/sudoers.d/10-elementary
root@daily:~# exit

… and then we rename the user to elementary:

$ sudo lxc exec daily -- sudo  -s -- <<EOF
usermod -l elementary ubuntu
groupmod -n elementary ubuntu
usermod -d /home/elementary -m elementary
usermod -c "elementary OS Daily" elementary
EOF

Now you should be able to jump into the container using the elementary user:

$ sudo lxc exec daily -- sudo --user elementary --login
To run a command as administrator (user "root"), use "sudo <command>".
See "man sudo_root" for details.

Setup elementary OS PPAs

Jump into the newly created daily container and setup all needed elementary OS PPAs:

elementary@daily:~$ sudo -s -- <<EOF
apt update
apt -y install software-properties-common
add-apt-repository -u -y ppa:elementary-os/os-patches
add-apt-repository -u -y ppa:elementary-os/stable
add-apt-repository -u -y ppa:elementary-os/daily
EOF

Install elementary OS packages

Next install the elementary OS packages in the daily container (this may take a while):

elementary@daily:~$ sudo -s -- <<EOF
apt update
apt install -y elementary-os-overlay elementary-desktop
apt -y dist-upgrade
apt -y autoremove
apt autoclean
EOF

Configure AppCenter repository in Container

elementary@daily:~$ sudo -s -- <<EOF
bash -c 'echo "deb http://packages.elementary.io/appcenter bionic main" >> /etc/apt/sources.list.d/appcenter.list'
wget -O /etc/apt/trusted.gpg.d/appcenter.asc http://packages.elementary.io/key.asc
apt update
EOF

Fix permission issues

elementary@daily:~$ sudo -s -- <<EOF
chown elementary:elementary ~/.cache/dconf/user
chown -R elementary:elementary ~/.cache
EOF

Restart LXD Container

Make sure you are in the Terminal of the host machine to restart the daily container:

$ sudo lxc restart daily

Verify

$ sudo lxc exec daily -- sudo --user elementary --login
elementary@daily:~$ lsb_release -a
No LSB modules are available.
Distributor ID:	elementary
Description:	elementary OS 5.1.3 Hera
Release:	5.1.3
Codename:	hera

# the following command should start the AppCenter GUI application:
elementary@daily:~$ sudo io.elementary.appcenter

Auto-Update the Container

To install the latest and greatest packages from elementary daily automatically, we setup the following CronJob for root in the daily container:

$ sudo lxc exec daily -- sudo --user elementary --login
elementary@daily:~$ sudo crontab -e
...
#
# m h  dom mon dow   command
0 9 * * * apt update && apt upgrade -y

This means the container gets updated with all the latest packages available every day at 9 AM. Feel free to adjust this however you like (crontab.guru may help creating the right expression).

To check whether the job was saved sucessfully, execute the following command:

elementary@daily:~$ sudo crontab -l

Install the elementary SDK

At this point you setup a completely independent development environment in a LXD container. That said, you can install all needed software within the container without affecting your host machine, which probably runs elementary stable.

In order to be able to develop elementary apps within the container, you need to install the elementary-sdk in it:

$ sudo lxc exec daily -- sudo --user elementary --login
elementary@daily:~$ sudo apt install elementary-sdk

Usage of daily container

See this dedicated usage page for further information how to work with the container.

Sources