Real-time Ubuntu¶

Tested: Ubuntu 22.04 LTS with RT kernel version 5.15.

You need an Ubuntu Pro subscription (free for personal use). Get your token at https://ubuntu.com/pro/dashboard.

This will install a specific RT kernel version, see RT Ubuntu releases. If you want to build a real-time kernel patch for your specific kernel version from source, see Franka docs.

You will need to re-install NVIDIA CUDA drivers after enabling real-time kernel. Download a CUDA runfile installer before proceeding. The runfile installer (with DKMS) is easier for RT Ubuntu setup than Ubuntu's packaged ones, which may not match the RT kernel.

1) Install RT kernel¶

# Dependencies
sudo apt update && sudo apt install -y \
    python3-dev \
    build-essential \
    mokutil

# Check that secure boot is disabled
sudo mokutil --sb-state

# Attach Ubuntu Pro (free personal plan allows up to 5 machines)
sudo pro attach <YOUR-TOKEN>

# Enable RT kernel
sudo pro enable realtime-kernel

# Set IGNORE_PREEMPT_RT_PRESENCE persistently
sudo grep -qxF 'IGNORE_PREEMPT_RT_PRESENCE=1' /etc/environment || echo 'IGNORE_PREEMPT_RT_PRESENCE=1' | sudo tee -a /etc/environment > /dev/null

# Re-install NVIDIA CUDA drivers
sudo IGNORE_PREEMPT_RT_PRESENCE=1 bash cuda_<VERSION>.run

# Update initramfs (in case RT kernel version is different than current one)
sudo update-initramfs -u -k all
# get /dev/<name> of root directory
df -h /
# update grub on root drive
sudo grub-install /dev/<name>
sudo update-grub

# Add user to realtime group
sudo addgroup realtime
sudo usermod -a -G realtime $(whoami)
# Update realtime group limits
sudo tee -a /etc/security/limits.conf >/dev/null <<'EOF'
@realtime soft rtprio 99
@realtime soft priority 99
@realtime soft memlock 102400
@realtime hard rtprio 99
@realtime hard priority 99
@realtime hard memlock 102400
EOF

# Make sure Performance mode is enabled
cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

# Reboot to load the new RT kernel
sudo reboot

2) Verify install¶

# Verify you're actually on an RT kernel, "-realtime"
uname -r
# should show 1
cat /sys/kernel/realtime

# Check NVIDIA modules are present/loaded
nvidia-smi
lsmod | grep -i nvidia

# Look for DKMS build issues
sudo journalctl -k -b | grep -i -E "nvidia|dkms|module"

# Confirm PREEMPT_RT config
grep PREEMPT_RT /boot/config-$(uname -r)

3) Additional setup for NUC¶

See "Step 4: Set up CPU monitoring utilities." from deoxys/System Prerequisite.

Anydesk¶

Requirements: a dummy HDMI or DisplayPort plug.

# install anydesk
sudo su root
wget -qO - https://keys.anydesk.com/repos/DEB-GPG-KEY | apt-key add -
echo "deb http://deb.anydesk.com/ all main" > /etc/apt/sources.list.d/anydesk-stable.list
apt update
apt install anydesk
echo <password> | anydesk --set-password
cat /dev/null > ~/.bash_history
anydesk --get-id
anydesk --get-status
# for "ERROR: display_server_not_supported", see https://askubuntu.com/a/1148504

# restart display manager
sudo systemctl restart gdm3

# open a terminal after signing in to anydesk window
sudo xhost +local:
sudo su $USER
tmux new -s anydesk
# detach tmux session

# attach tmux session in another terminal
ssh $USER@$SERVER
tmux attach -t anydesk
xeyes
# should show up in anydesk window