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Ghaf Framework

Ghaf Architecture Overview

Ghaf Architecture Overview

Section titled “Ghaf Architecture Overview”

Ghaf implements a comprehensive security framework for edge devices through compartmentalization, virtualization, and zero-trust principles. This document provides detailed architectural insights into the system design and implementation.

System Architecture Layers

Section titled “System Architecture Layers”

Layer 1: Hardware Abstraction

Section titled “Layer 1: Hardware Abstraction”

Purpose: Provide unified interface across diverse hardware platforms Components:

  • Hardware detection and configuration
  • Driver management and isolation
  • Platform-specific optimizations
  • Secure boot and attestation

Supported Platforms:

  • x86_64: Intel/AMD processors with VT-x/AMD-V
  • AArch64: ARM Cortex-A processors with virtualization extensions
  • RISC-V: PolarFire and compatible RISC-V processors

Layer 2: Hypervisor and Virtualization

Section titled “Layer 2: Hypervisor and Virtualization”

Purpose: Secure isolation and resource management Technology: NixOS + MicroVM framework Features:

  • Type-1 hypervisor capabilities through NixOS
  • MicroVM for lightweight guest execution
  • Hardware-assisted virtualization
  • GPU passthrough and sharing

Layer 3: Guest Operating Systems

Section titled “Layer 3: Guest Operating Systems”

Purpose: Isolated execution environments Guest Types:

  • Application VMs: Browser, office, development tools
  • Service VMs: Network services, system utilities
  • Windows VMs: Legacy application compatibility
  • Specialty VMs: Hardware-specific or security-focused

Layer 4: Inter-VM Communication

Section titled “Layer 4: Inter-VM Communication”

Purpose: Secure, controlled communication between isolated environments Technology: GIVC (Guest Inter-VM Communication) Features:

  • Authenticated message passing
  • Resource sharing protocols
  • File transfer with security scanning
  • Display and input redirection

Layer 5: Host Services

Section titled “Layer 5: Host Services”

Purpose: System-wide services and management Services:

  • VM lifecycle management
  • Network configuration and isolation
  • Storage management and encryption
  • System monitoring and logging

Security Architecture

Section titled “Security Architecture”

Zero Trust Principles

Section titled “Zero Trust Principles”
  1. Never Trust, Always Verify: All components must authenticate
  2. Least Privilege Access: Minimal permissions for each component
  3. Assume Breach: Design for containment and recovery
  4. Continuous Monitoring: Real-time security state assessment

Isolation Boundaries

Section titled “Isolation Boundaries”
┌─────────────────────────────────────────────────────┐
│                    Host System                      │
│  ┌─────────────┐  ┌─────────────┐  ┌─────────────┐  │
│  │ Browser VM  │  │ Office VM   │  │ Dev VM      │  │
│  │ (Untrusted) │  │ (Trusted)   │  │ (Trusted)   │  │
│  └─────────────┘  └─────────────┘  └─────────────┘  │
│         │                 │                 │       │
│  ┌─────────────────────────────────────────────────┐  │
│  │           GIVC Communication Layer           │  │
│  └─────────────────────────────────────────────────┘  │
│  ┌─────────────────────────────────────────────────┐  │
│  │            Host Security Services            │  │
│  └─────────────────────────────────────────────────┘  │
└─────────────────────────────────────────────────────┘

Trust Levels

Section titled “Trust Levels”
  • Untrusted: Internet-facing applications (browser, email)
  • Trusted: Business applications (office, development)
  • System: Core system services and management
  • Hardware: TPM, secure elements, hardware attestation

Network Architecture

Section titled “Network Architecture”

Network Segmentation

Section titled “Network Segmentation”

Each VM operates in isolated network segments with controlled routing:

Internet ← NAT Gateway ← Firewall ← Network Bridge ← VM Network
                           │
                           ├── Browser VM (DMZ)
                           ├── Office VM (Work)
                           ├── Dev VM (Development)
                           └── Management (System)

Network Policies

Section titled “Network Policies”
  • Default Deny: All traffic blocked by default
  • Explicit Allow: Each connection requires explicit policy
  • Traffic Inspection: Deep packet inspection at boundaries
  • VPN Integration: Site-to-site and client VPN support

Storage Architecture

Section titled “Storage Architecture”

Encrypted Storage Stack

Section titled “Encrypted Storage Stack”
Application Data
      │
   VM Filesystem (ext4/btrfs)
      │
   dm-crypt Encryption
      │
   LVM Volume Management
      │
   Physical Storage (NVMe/eMMC)

Storage Isolation

Section titled “Storage Isolation”
  • Per-VM Storage: Isolated filesystem containers
  • Shared Storage: Controlled shared volumes with access controls
  • Encrypted Swap: Memory encryption for sensitive data
  • Secure Deletion: Cryptographic erasure capabilities

Development Architecture

Section titled “Development Architecture”

Build System

Section titled “Build System”

Technology: Nix flakes with flake-parts organization Benefits:

  • Reproducible builds across environments
  • Hermetic build isolation
  • Cross-platform compilation support
  • Dependency management and caching

Module System

Section titled “Module System”

Ghaf uses a hierarchical module system:

ghaf.nix (root)
├── common/ (base system)
├── profiles/ (system profiles)
├── hardware/ (platform support)
├── reference/ (examples)
├── development/ (dev tools)
└── virtualization/ (VM management)

Configuration Management

Section titled “Configuration Management”
  • Declarative Configuration: All system state in Nix expressions
  • Version Control Integration: Configuration versioning and rollback
  • Staged Deployment: Gradual rollout with automated testing
  • A/B Updates: Atomic system updates with fallback

Performance Architecture

Section titled “Performance Architecture”

Resource Management

Section titled “Resource Management”
  • CPU Isolation: Dedicated cores for critical VMs
  • Memory Management: NUMA-aware allocation
  • I/O Prioritization: QoS for storage and network
  • GPU Scheduling: Time-slice GPU sharing between VMs

Optimization Strategies

Section titled “Optimization Strategies”
  • Paravirtualization: Optimized guest drivers
  • Memory Ballooning: Dynamic memory allocation
  • Copy-on-Write: Efficient storage utilization
  • Kernel Bypass: DPDK and SPDK for high-performance I/O

Scalability Architecture

Section titled “Scalability Architecture”

Horizontal Scaling

Section titled “Horizontal Scaling”
  • Container Integration: Kubernetes and OCI compatibility
  • Cluster Management: Multi-node deployment support
  • Load Balancing: Traffic distribution across instances
  • Auto-scaling: Dynamic resource allocation

Vertical Scaling

Section titled “Vertical Scaling”
  • Resource Elasticity: Dynamic CPU/memory allocation
  • Storage Expansion: Hot-pluggable storage devices
  • Network Scaling: Multi-gigabit network support
  • GPU Scaling: Multi-GPU support and sharing

Integration Architecture

Section titled “Integration Architecture”

API Framework

Section titled “API Framework”

Technology: RESTful APIs with gRPC for high-performance Authentication: mTLS with certificate-based identity Authorization: RBAC with fine-grained permissions

External Integrations

Section titled “External Integrations”
  • Identity Providers: LDAP, Active Directory, SAML, OIDC
  • Monitoring Systems: Prometheus, Grafana, ELK stack
  • Backup Solutions: Restic, Borg, cloud storage
  • Management Platforms: Ansible, Terraform, Kubernetes

Deployment Architecture

Section titled “Deployment Architecture”

Image Generation

Section titled “Image Generation”

Multiple deployment formats from single configuration:

  • ISO Images: Bootable installation media
  • VM Images: QEMU, VMware, VirtualBox
  • Container Images: OCI-compatible containers
  • Flash Images: Raw images for embedded devices

Update Mechanisms

Section titled “Update Mechanisms”
  • Atomic Updates: All-or-nothing system updates
  • Rollback Capability: Instant rollback to previous state
  • Staged Rollout: Gradual deployment with health checks
  • Emergency Recovery: Secure boot fallback mechanisms

Monitoring and Observability

Section titled “Monitoring and Observability”

Metrics Collection

Section titled “Metrics Collection”
  • System Metrics: CPU, memory, storage, network utilization
  • Security Metrics: Failed authentications, policy violations
  • Performance Metrics: VM startup times, I/O latency
  • Business Metrics: Application usage, user activities

Logging Architecture

Section titled “Logging Architecture”
Application Logs → VM Syslog → Host Aggregator → Central Logging
Security Events → Audit Daemon → SIEM Integration → Alert Manager
Performance Data → Metrics Collector → Time Series DB → Dashboard

Alerting Framework

Section titled “Alerting Framework”
  • Real-time Alerts: Security incidents, system failures
  • Predictive Alerts: Resource exhaustion, performance degradation
  • Compliance Alerts: Policy violations, audit failures
  • Recovery Alerts: Automated remediation status

Next Steps

Section titled “Next Steps”