systemd-user-runtime-dir Failed to remove runtime directory

Issue

# systemctl -t service --failed
UNIT LOAD ACTIVE SUB DESCRIPTION
● [e-mail] loaded failed failed User runtime directory /run/user/1043
● [e-mail] loaded failed failed User runtime directory /run/user/1203

Environment

• CloudLinux 8

Solution

1. Create a drop-in to make sure that user-runtime-dir@.service unit is a one-shot service

   # mkdir -p /etc/systemd/system/user-runtime-dir@.service.d
   # cat > /etc/systemd/system/user-runtime-dir@.service.d/kcs_5931241.conf << EOF
   [Service]
   Type=oneshot
   EOF
   

2. Reload systemd for change to take effect

   # systemctl daemon-reload
   

3. Clear the failing state

   # systemctl reset-failed
   

Cause

There is a race between the unit preparing the temporary file system used to provide /run/user/<UID> and the startup of systemd --user instance.
It also could happen when some processes stay in uninterruptible wait during logout and the error can be safely ignored.