Fleet Device Management

Fleet is an open-source device management platform that uses osquery to provide visibility and control over your device fleet. In Ghaf, Fleet Orbit is integrated to enable centralized device management, monitoring, and remote script execution.

Overview

The Fleet integration in Ghaf provides:

• Device Visibility: Query device state, installed software, and system configuration
• Remote Management: Execute scripts and commands on managed devices
• Policy Enforcement: Define and monitor compliance policies
• Fleet Desktop: User-facing tray application for device status

Fleet Orbit runs in the GUI VM and reports to a central Fleet server using a dynamic hostname derived from the device hardware, ensuring consistent identification across reboots.

Architecture

┌─────────────────────────────────────────────────────────────┐
│                        Host VM                               │
│  ┌─────────────────────────────────────────────────────┐    │
│  │  ghaf-dynamic-hostname service                       │    │
│  │  └─► /persist/common/ghaf/hostname                   │    │
│  └─────────────────────────────────────────────────────┘    │
│                           │ (virtiofs)                       │
└───────────────────────────┼─────────────────────────────────┘
                            │
┌───────────────────────────┼─────────────────────────────────┐
│                        GUI VM                                │
│                           ▼                                  │
│  ┌─────────────────────────────────────────────────────┐    │
│  │  /etc/common/ghaf/hostname                           │    │
│  └──────────────────────┬──────────────────────────────┘    │
│                         │                                    │
│  ┌──────────────────────▼──────────────────────────────┐    │
│  │  orbit.service                                       │    │
│  │  └─► ORBIT_HOSTNAME_FILE=/etc/common/ghaf/hostname   │    │
│  │  └─► Reports to Fleet Server                         │    │
│  └─────────────────────────────────────────────────────┘    │
│                                                              │
│  ┌─────────────────────────────────────────────────────┐    │
│  │  fleet-desktop.service (user)                        │    │
│  │  └─► Tray icon for device status                     │    │
│  └─────────────────────────────────────────────────────┘    │
└─────────────────────────────────────────────────────────────┘

Configuration

Fleet is configured in the GUI VM via services.orbit. The following example shows the default configuration:

services.orbit = {
  enable = true;
  fleetUrl = "https://your-fleet.example.com";
  enrollSecret = "your-enroll-secret";       # Use enrollSecretPath for production
  hostnameFile = "/etc/common/ghaf/hostname"; # Dynamic hostname from host
  enableScripts = true;                       # Allow remote script execution
};

Configuration Options

Option	Environment Variable	Description
enable	—	Enable Fleet Orbit systemd service
fleetUrl	ORBIT_FLEET_URL	Base URL of the Fleet server
enrollSecret	ORBIT_ENROLL_SECRET	Enroll secret for Fleet server
enrollSecretPath	ORBIT_ENROLL_SECRET_PATH	Path to enroll secret file (recommended for production)
fleetCertificate	ORBIT_FLEET_CERTIFICATE	Path to Fleet server certificate chain
hostnameFile	ORBIT_HOSTNAME_FILE	Path to file containing hostname (Ghaf-specific)
hostIdentifier	ORBIT_HOST_IDENTIFIER	Host identifier mode: uuid or instance
enableScripts	ORBIT_ENABLE_SCRIPTS	Enable remote script execution
debug	ORBIT_DEBUG	Enable debug logging
insecure	ORBIT_INSECURE	Disable TLS certificate verification

Secret Management

For production deployments, use enrollSecretPath with a secrets management solution like sops-nix:

services.orbit = {
  enable = true;
  fleetUrl = "https://fleet.example.com";
  enrollSecretPath = config.sops.secrets.fleet-enroll-secret.path;
  hostnameFile = "/etc/common/ghaf/hostname";
};

sops.secrets.fleet-enroll-secret = {
  sopsFile = ./secrets.yaml;
};

For CI/dev images, keep secrets out of the image and inject the enroll secret at
runtime. Ghaf uses a shared host path for dynamic hostname; you can reuse the
same mechanism for the enroll secret (for example, `/etc/common/ghaf/fleet/enroll`
inside the guest).

Dynamic Hostname

Ghaf uses hardware-derived hostnames for device identification. The ghaf-dynamic-hostname service on the host generates a unique hostname based on hardware identifiers (DMI serial, disk UUID, or MAC address) and writes it to /persist/common/ghaf/hostname.

This file is shared with VMs via virtiofs and mounted at /etc/common/ghaf/hostname. The Fleet module is patched to read the hostname from this file via the hostnameFile option, ensuring devices are consistently identified on the Fleet server.

The orbit service includes a ConditionPathExists directive to wait for the hostname file before starting.

Systemd Services

Two systemd services are created:

• orbit.service (system): Runs the Orbit agent, connecting to the Fleet server
• fleet-desktop.service (user): Runs Fleet Desktop tray application in graphical sessions

Logs

Orbit logs are written to:

• /var/log/orbit/orbit.log — Main Orbit log
• /var/log/orbit/osquery/ — osquery result and status logs
• journalctl -u orbit — Systemd journal

NixOS-Specific Considerations

The Ghaf Fleet integration includes patches for NixOS compatibility:

• Disabled auto-updates: NixOS manages packages declaratively; Orbit’s auto-update is disabled
• Disabled keystore: Secrets are not stored in OS-specific keystores
• Fixed paths: osqueryd binary path is set from Nix store
• Shebang patching: Remote scripts have shebangs patched to use NixOS paths

Troubleshooting

Orbit not starting

Check if the hostname file exists:

ls -la /etc/common/ghaf/hostname

Check service status:

systemctl status orbit
journalctl -u orbit -f

Connection issues

Enable debug logging:

services.orbit = {
  debug = true;
  # For testing only:
  # insecure = true;
};

Script execution failures

Verify scripts are enabled and check logs:

cat /var/log/orbit/orbit.log | grep -i script

References

• Fleet Documentation
• osquery Documentation
• Dynamic Hostname Generation — Ghaf hardware-derived hostname system