Apptainer Desktop Container Example

Get Help
1

Hey there

I’m working on providing a XFCE desktop for users. From previous threads here in the forum I believe there are working setups around. Unfortunately, I wasn’t able to find a full example somewhere and wasn’t able to piece a working one together.

My goal is to provide a XFCE desktop based on Rocky Linux 9 (which our HPC currently runs on). I’m currently using a version of the example code from the OOD documentation (Batch Connect VNC Container Options — Open OnDemand 4.0.0 documentation), adapted for Rocky 9, to create the container:

Bootstrap: docker
From: rockylinux/rockylinux:9-minimal

%environment
  PATH=/opt/TurboVNC/bin:$PATH
  LANGUAGE="en_US.UTF-8"
  LC_ALL="en_US.UTF-8"
  LANG="en_US.UTF-8"

%post
    microdnf -y install dnf
    dnf install -y dnf-plugins-core
    dnf config-manager --set-enabled crb
    dnf -y update && dnf -y upgrade
    dnf install -y epel-release
    dnf install -y xfdesktop xfwm4 xfce4-session xfce4-settings xfce4-terminal
    dnf install -y xkbcomp
    dnf install -y python3-pip xorg-x11-xauth
    pip3 install ts
    dnf install -y https://yum.osc.edu/ondemand/latest/compute/el9Server/x86_64/python3-websockify-0.11.0-1.el9.noarch.rpm
    dnf install -y https://yum.osc.edu/ondemand/latest/compute/el9Server/x86_64/turbovnc-3.1.1-1.el9.x86_64.rpm 
    dnf clean all
    chown root:root /opt/TurboVNC/etc/turbovncserver-security.conf
    rm -rf /var/cache/dnf/*
    rm -f /var/log/*.log

My submit.yml.erb uses the ‘vnc_container’ template from batch_connect:
---
batch_connect:
template: "vnc_container"
websockify_cmd: "/usr/bin/websockify"
container_path: "/path/to/xfce-desktop.sif"
container_bindpath: ""
container_module: ""
container_command: "apptainer"
script:
native:
(SLURM parameters to run the job on our HPC)

Unfortunately, I haven’t found any matching script.sh.erb file to properly run the container. One thread suggested to just copy the xfce.sh script from the batch_connect template (template/desktops/xfce.sh) and run it inside the container. But that didn’t work for me.

I previously created a native desktop (where the xfce desktop environment is running locally on the compute node of the cluster) with some customization and tried to reuse the commands by running them inside the container. The resulting script.sh.erb:

#!/usr/bin/env bash

# Clean the environment
module purge

# Set working directory to home directory
cd "${HOME}"

# xfce configuration maintenance
## Clean up previous monitors
if [[ -f "${HOME}/.config/monitors.xml" ]]; then
  mv "${HOME}/.config/monitors.xml" "${HOME}/.config/monitors.xml.bak"
fi

## Copy over default panel if doesn't exist, otherwise it will prompt the user
PANEL_CONFIG="${HOME}/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-panel.xml"
if [[ ! -e "${PANEL_CONFIG}" ]]; then
  mkdir -p "$(dirname "${PANEL_CONFIG}")"
  cp "/etc/xdg/xfce4/panel/default.xml" "${PANEL_CONFIG}"
fi

## Set Xfce4 Terminal as login shell (sets proper TERM)
TERM_CONFIG="${HOME}/.config/xfce4/terminal/terminalrc"
if [[ ! -e "${TERM_CONFIG}" ]]; then
  mkdir -p "$(dirname "${TERM_CONFIG}")"
  sed 's/^ \{4\}//' > "${TERM_CONFIG}" << EOL
    [Configuration]
    CommandLoginShell=TRUE
EOL
else
  sed -i \
    '/^CommandLoginShell=/{h;s/=.*/=TRUE/};${x;/^$/{s//CommandLoginShell=TRUE/;H};x}' \
    "${TERM_CONFIG}"
fi

#
# Launch Xfce Window Manager and Panel
#
echo "Setting environment variables..."

# configure DISPLAY for container
export APPTAINERENV_DISPLAY=$DISPLAY
export SEND_256_COLORS_TO_REMOTE=1
export APPTAINERENV_SEND_256_COLORS_TO_REMOTE="$SEND_256_COLORS_TO_REMOTE"

# Set the user folder
export XDG_CONFIG_HOME="<%= session.staged_root.join("config") %>"
export APPTAINERENV_XDG_CONFIG_HOME="$XDG_CONFIG_HOME"

export XDG_DATA_HOME="<%= session.staged_root.join("share") %>"
export APPTAINERENV_XDG_DATA_HOME="$XDG_DATA_HOME"

export APPTAINERENV_PATH=$PATH
export APPTAINERENV_LD_LIBRARY_PATH=$LD_LIBRARY_PATH

echo "Starting desktop instance"

module restore
set -x

# Launch dbus-launch with full path to prevent conda PATH issues (https://github.com/OSC/ondemand/issues/700)
export $(apptainer exec instance://$INSTANCE_NAME /usr/bin/dbus-launch 2>/dev/null)
export APPTAINERENV_DBUS_SESSION_BUS_ADDRESS=$DBUS_SESSION_BUS_ADDRESS
export APPTAINERENV_DBUS_SESSION_BUS_PID=$DBUS_SESSION_BUS_PID

echo "Starting xfce desktop..."

# Launche xfce window manager
apptainer exec instance://$INSTANCE_NAME xfwm4 --compositor=off --sm-client-disable
#
apptainer exec instance://$INSTANCE_NAME xsetroot -solid "#D3D3D3"
#
apptainer exec instance://$INSTANCE_NAME xfsettingsd --sm-client-disable --daemon
# disable ssh autostart
apptainer exec instance://$INSTANCE_NAME xfconf-query -c xfce4-session -p /startup/ssh-agent/enabled -n -t bool -s false
# disable gpg autostart
apptainer exec instance://$INSTANCE_NAME xfconf-query -c xfce4-session -p /startup/gpg-agent/enabled -n -t bool -s false
# launch the desktop panel (used by HPC to monitor if desktop is still running)
apptainer exec instance://$INSTANCE_NAME xfce4-panel --sm-client-disable

But this did not work as expected. The session (and desktop) is starting, but noVNC can’t connect to it.

Since I’m not sure if the root cause of the this is related to an error in my configuration or if there is some setting missing on our HPC, I’d appreciate if someone could share a working example for running a desktop container so I can test if this is working here.

Please let me know if you want to inspect additional files (or if you maybe already have spotted the error?). I’d really appreciate any support or examples.

2

We don’t use this at OSC, but I can take a crack at replicating and see what I can see.