systemd

Overview ¶

Package systemd collects systemd service configuration data.

This collector gathers configuration and runtime status for critical system services that affect GPU and Kubernetes operation, such as containerd, docker, and kubelet.

Collected Data ¶

For each configured service, the collector captures:

• Service state (active, inactive, failed)
• Startup configuration (enabled, disabled)
• Resource limits (CPU, Memory, Tasks)
• Execution settings (User, Group, WorkingDirectory)
• Dependencies (Wants, Requires, After, Before)
• Security settings (ProtectSystem, PrivateTmp, NoNewPrivileges)

Usage ¶

Create with specific services to monitor:

collector := systemd.NewCollector([]string{
    "containerd.service",
    "kubelet.service",
    "docker.service",
})

measurements, err := collector.Collect(ctx)
if err != nil {
    log.Fatal(err)
}

for _, m := range measurements {
    for _, subtype := range m.Subtypes {
        fmt.Printf("Service: %s\n", subtype.Name)
        if state, ok := subtype.Data["ActiveState"]; ok {
            fmt.Printf("  State: %s\n", state)
        }
    }
}

Service Configuration ¶

Services to monitor are specified during collector creation:

services := []string{
    "containerd.service",
    "kubelet.service",
}
collector := systemd.NewCollector(services)

Common services for GPU clusters:

• containerd.service: Container runtime
• docker.service: Docker daemon (alternative runtime)
• kubelet.service: Kubernetes node agent
• nvidia-dcgm.service: NVIDIA DCGM monitoring
• nvidia-persistenced.service: GPU persistence daemon

Data Format ¶

Each service becomes a subtype with configuration key-value pairs:

{
    Type: "systemd",
    Subtypes: [
        {
            Name: "containerd.service",
            Data: {
                "ActiveState": "active",
                "UnitFileState": "enabled",
                "CPUAccounting": "yes",
                "MemoryAccounting": "yes",
                "MemoryLimit": "infinity",
                ...
            }
        }
    ]
}

Context Support ¶

The collector respects context cancellation:

ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()

measurements, err := collector.Collect(ctx)

Error Handling ¶

The collector continues on non-critical errors:

• Service not found: Includes note in subtype data
• Service not loaded: Captures available properties
• systemctl not available: Returns error

Critical errors (systemd not available) cause the entire collection to fail.

systemd Integration ¶

The collector uses `systemctl show` to query service properties:

systemctl show containerd.service --property=ActiveState --property=UnitFileState

This provides reliable, machine-readable output that works across all systemd-based distributions.

Use in Recipes ¶

Recipe generation uses systemd data for:

• Service dependency verification
• Resource limit recommendations
• Security policy validation
• Startup configuration tuning
• Service state troubleshooting