kubernetes/kops · warning

error listing systemd units: %v

Error message

error listing systemd units: %v

What it means

Returned by logDumperNode.listSystemdUnits (pkg/dump/dumper.go:550) when the SSH ExecPiped of `sudo systemctl list-units -t service --no-pager --no-legend --all` fails. This is the root-cause error surfaced (wrapped) to callers as 'error listing systemd services'; it prevents matching the dumper's configured service list against the node's actual units.

Source

Thrown at pkg/dump/dumper.go:550

	paths := []string{}
	for _, b := range bytes.Split(stdout.Bytes(), []byte{0}) {
		if len(b) == 0 {
			// Likely the last value
			continue
		}
		paths = append(paths, string(b))
	}
	return paths, nil
}

// listSystemdUnits returns the list of systemd units on the node
func (n *logDumperNode) listSystemdUnits(ctx context.Context) ([]string, error) {
	var stdout bytes.Buffer
	var stderr bytes.Buffer

	err := n.client.ExecPiped(ctx, "sudo systemctl list-units -t service --no-pager --no-legend --all", &stdout, &stderr)
	if err != nil {
		return nil, fmt.Errorf("error listing systemd units: %v", err)
	}

	var services []string
	for _, line := range strings.Split(stdout.String(), "\n") {
		tokens := strings.Fields(line)
		if len(tokens) == 0 || tokens[0] == "" {
			continue
		}
		services = append(services, tokens[0])
	}
	return services, nil
}

// shellToFile executes a command and copies the output to a file
func (n *logDumperNode) shellToFile(ctx context.Context, command string, destPath string) error {
	if err := os.MkdirAll(filepath.Dir(destPath), 0o755); err != nil {
		klog.Warningf("unable to mkdir on %q: %v", filepath.Dir(destPath), err)
	}

View on GitHub (pinned to 4c8573c808)

Solutions

1. SSH to the node and run the exact systemctl command to see the real exit code/stderr.
2. If systemctl is absent (non-systemd image), accept the warning or switch to a systemd-based node image.
3. Ensure passwordless sudo (NOPASSWD) is configured for the dump user.
4. Raise --node-dump-timeout if the error wraps context.DeadlineExceeded.
5. Retry the dump; check node health (dmesg, disk, memory) if systemctl hangs or fails intermittently.

// verify systemctl presence and sudo access before listing units
err := n.client.ExecPiped(ctx, "command -v systemctl && sudo -n true", io.Discard, io.Discard)
if err != nil {
    return nil, fmt.Errorf("node not systemd/sudo ready: %w", err)
}

services, err := n.listSystemdUnits(ctx)
if err != nil {
    if errors.Is(err, context.DeadlineExceeded) {
        klog.Warningf("systemctl listing timed out; raise --node-dump-timeout")
    }
    return nil, fmt.Errorf("error listing systemd units: %w", err)
}

When it happens

Trigger: ExecPiped fails because: systemctl is not installed (non-systemd image like Alpine), the remote command exits non-zero (sudo denied), the SSH session is closed/reset, or the dumpNode context (1-minute nodeDumpTimeout) expires before the command finishes.

Common situations: Dumping nodes built from non-systemd base images; sudoers requiring a TTY/password; node under heavy load or out of memory so systemctl is slow; SSH session killed by network middleboxes during long dumps.

Related errors

• error listing systemd services: %v
• error reading /var/log: %v
• error listing /etc/containerd: %v
• error listing %q: %v
• connecting: %w

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/c36e6ff5cf3ac5af. Report an issue: GitHub.