Xpra: Ticket #2042: Failed to add PIDs to scope's control group: Permission denied

I am on the server side, an Ubuntu 18.04, with xpra version 2.1.3.

When I try:

rmagno@r2d2:~$ PATH="/usr/lib/xorg:$PATH" xpra start --bind-tcp=0.0.0.0:14500 --html=on --start=xterm

I get:

using systemd-run to wrap 'start' server command
'systemd-run' '--description' 'xpra-start' '--scope' '--user' '/usr/bin/xpra' 'start' '--bind-tcp=0.0.0.0:14500' '--html=on' '--start=xterm' '--systemd-run=no'
Job for run-rc4c6fd6f0a8445b08d9bfb1da717308c.scope failed.
See "systemctl status run-rc4c6fd6f0a8445b08d9bfb1da717308c.scope" and "journalctl -xe" for details.

then journalctl -xe shows me:

Nov 16 07:35:28 r2d2 systemd[26686]: run-rb32e0e35376249e1b0d77b784c1beffb.scope: Failed to add PIDs to scope's control group: Permission denied
Nov 16 07:35:28 r2d2 systemd[26686]: run-rb32e0e35376249e1b0d77b784c1beffb.scope: Failed with result 'resources'.
Nov 16 07:35:28 r2d2 systemd[26686]: Failed to start xpra-start.


Fri, 16 Nov 2018 08:09:52 GMT - Antoine Martin: status changed; resolution set

Is this from an SSH session? This works fine from a regular terminal in my Ubuntu 18.04 VM.

That said, I'm using a supported version (2.4.1) and you are not (2.1.3). Please do not use the version provided by the Ubuntu repositories which is fundamentally broken and insecure (more details here: wiki/Packaging/DistributionPackages)


Fri, 16 Nov 2018 15:03:27 GMT - Ramiro: status changed; resolution deleted

Could you please instruct me on how to install version 2.4.1 under Ubuntu 18.04?

And yes, I am trying to run that command from an SSH session.

BTW: How to check xpra version?


Fri, 16 Nov 2018 15:17:30 GMT - Ramiro: attachment set

connect.html error msg


Fri, 16 Nov 2018 15:19:32 GMT - Antoine Martin: status changed; resolution set

Could you please instruct me on how to install version 2.4.1 under Ubuntu 18.04?

See wiki/Download.

And yes, I am trying to run that command from an SSH session.

This can cause problems under some circumstances. If you still encounter issues after upgrading, start your sessions first, then connect over ssh - rather than doing all in one.

BTW: How to check xpra version?

xpra --version


Sat, 19 Jan 2019 15:50:43 GMT - snhirsch: status changed; resolution deleted

I suddenly started seeing exactly the same symptoms on my Ubuntu 18.04 system when running from a standard Xterm (NOT ssh session). Was working fine until several days ago when, I suspect, a Ubuntu update broke it.

I followed the directions to install directly from your repository, but apparently the Ubuntu package is newer and nothing was brought down.

xpra --version yields: xpra v2.5-r21174


Sat, 19 Jan 2019 15:51:12 GMT - snhirsch: cc set


Sat, 19 Jan 2019 16:21:52 GMT - snhirsch:

More information: The root cause of this problem is related to cgroup permissions. If I hack ownership with this script things start working again.

#!/usr/bin/env bash
set -euo pipefail
file=/sys/fs/cgroup/unified/user.slice/user-$(id -u).slice/cgroup.procs
sudo chown $(whoami):root $file
sudo chmod g+w            $file

Sat, 19 Jan 2019 17:02:16 GMT - Antoine Martin: status changed; resolution set

I followed the directions to install directly from your repository, but apparently the Ubuntu package is newer and nothing was brought down. xpra --version yields: xpra v2.5-r21174

Looks like you're using the beta channel.

Try the stable 2.4.3, which has this fix: r21227 Otherwise, I'll try to make new beta builds shortly.

You can also do:

echo "systemd-run=no" >> ~/.xpra/xpra.conf

Sat, 19 Jan 2019 18:55:23 GMT - snhirsch:

I am not using the beta channel. My winswitch.list file contains:

deb http://winswitch.org/ bionic main

There are no other references to winswitch anywhere in the apt configuration tree.


Sun, 20 Jan 2019 02:16:33 GMT - Antoine Martin:

I am not using the beta channel.

There are no 2.5 builds in the stable repository. I have no idea how it landed on your system.

Maybe try:

apt-get update
apt-get remove -y xpra
apt-get install -y xpra

Tue, 11 Feb 2020 04:51:40 GMT - Antoine Martin:

See also: ticket:2585#comment:1.


Sat, 23 Jan 2021 05:40:36 GMT - migration script:

this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/2042