---
title: "Systemd Session Scope Fails at Login (session-cN.scope)"
domain: troubleshooting
category: systemd
tags: [systemd, ssh, login, session, linux]
status: published
created: 2026-04-02
updated: 2026-04-02
---
# Systemd Session Scope Fails at Login (`session-cN.scope`)

After SSH login, systemd reports a failed transient unit like `session-c1.scope`. The MOTD or login banner shows `Failed Units: 1 — session-c1.scope`. This is a harmless race condition, not a real service failure.

## Symptoms

- Login banner or MOTD displays:
  ```
  Failed Units: 1
    session-c1.scope
  ```
- `systemctl list-units --failed` shows one or more `session-cN.scope` units in a failed state
- The system is otherwise healthy — no services are actually broken

## What Causes It

A transient session scope is created by systemd-logind every time a user logs in (SSH, console, etc.). The scope tracks the login session's process group via cgroups.

The failure occurs when a login process (PID) exits before systemd can move it into the target cgroup. This is a race condition triggered by:

- **Short-lived SSH connections** — automated probes, health checks, or monitoring tools that connect and immediately disconnect
- **Sessions that disconnect before PAM completes** — network interruptions or aggressive client timeouts
- **Cron jobs or scripts** that create transient SSH sessions

systemd logs the sequence:

1. `PID N vanished before we could move it to target cgroup`
2. `No PIDs left to attach to the scope's control group, refusing.`
3. Unit enters `failed (Result: resources)` state

Because session scopes are transient (not backed by a unit file), the failed state lingers until manually cleared.

## How to Diagnose

### 1. Check the failed unit

```bash
systemctl status session-c1.scope
```

Look for:

```
Active: failed (Result: resources)
```

And in the log output:

```
PID <N> vanished before we could move it to target cgroup
No PIDs left to attach to the scope's control group, refusing.
```

### 2. Confirm no real failures

```bash
systemctl list-units --failed
```

If the only failed units are `session-cN.scope` entries, the system is healthy.

## Fix

Reset the failed unit:

```bash
systemctl reset-failed session-c1.scope
```

To clear all failed session scopes at once:

```bash
systemctl reset-failed 'session-*.scope'
```

Verify:

```bash
systemctl list-units --failed
```

Should report 0 failed units.

## Notes

- This is a known systemd behavior and not indicative of a real problem. It can be safely ignored or cleared whenever it appears.
- If it recurs frequently, investigate what is creating short-lived SSH sessions — common culprits include monitoring agents (Netdata, Nagios), automated backup scripts, or SSH brute-force attempts.
- The `c` in `session-c1.scope` indicates a **console/SSH session** (as opposed to graphical sessions which use different prefixes). The number increments with each new session.
- Applies to **Fedora, Ubuntu, and any systemd-based Linux distribution**.

## Related

- [gitea-runner-boot-race-network-target](../gitea-runner-boot-race-network-target.md) — Another systemd race condition involving service startup ordering