KillUserProcesses

KillUserProcesses is a setting in systemd’s logind component that controls whether a user’s processes are terminated when the user logs out or ends a session. When enabled, logind will attempt to kill all processes owned by the user as part of the logout process.

Behavior and scope:

Upon session termination, systemd-logind identifies the user’s processes and sends termination signals. Typically, processes are first sent a polite signal (such as SIGTERM) to allow them to shut down gracefully, followed by SIGKILL for any remaining processes after a grace period. This behavior relies on the user’s session and associated control groups (cgroups) to target only the user’s processes and not system-wide or other users’ processes. The setting does not affect kernel threads or system services running under different users; it is scoped to the user’s login session.

Configuration and usage:

KillUserProcesses is configured in the file /etc/systemd/logind.conf. To enable it, set KillUserProcesses=yes and then restart the systemd-logind service (for example, systemctl restart systemd-logind) or reboot the system. The exact effect and any grace periods can vary somewhat with different systemd versions and distributions.

Considerations:

Enabling this option can prevent lingering or orphaned processes after logout and helps reclaim resources, but it can also lead to data loss if applications have unsaved work. Administrators should weigh the need for clean logouts against the potential impact on running user workloads. See also loginctl, systemd, and logind.conf for related session management features.