Munin plugins that I created.
Install with:
sudo ln -s /path/to/cpu_usage_by_user.py /etc/munin/plugins/cpu_usage_per_user
sudo ln -s /path/to/bin/ram_usage_by_user.py /etc/munin/plugins/ram_usage_per_user
sudo systemctl restart munin-node.service
Both plugins rely on using systemd-cgtop to get the total amount of CPU and RAM that users are using in their user slices.
This only works if systemd is running and CPU and RAM accounting are enabled system-wise.
Enable it by creating /etc/systemd/system.conf.d/10-enable_accounting.conf with:
[Manager]
DefaultCPUAccounting=yes
DefaultMemoryAccounting=yes
And then rebooting.
The script filters UID to be in the range 1000 to 2000. Edit it if you need so.
Another thing to note is that the amount of RAM reported seems to be the total commited RAM per user, not only active. The sum over all users can thus be greater than the total amount of RAM physically available.