Module boot_fsm 

Deterministic Boot Finite State Machine

Implements a production-grade boot sequence with:

• Well-defined states: Init → Migrate → Recover → Warmup → Ready
• Time budgets for each phase (for Kubernetes probe alignment)
• Progress reporting for external observability
• Recovery modes: Normal, ReadOnlyRecovery, ForceRecovery

Kubernetes Integration

The FSM exports progress metrics that align with K8s probe semantics:

• startupProbe: tolerates long recovery (uses recovery budget)
• readinessProbe: true only when FSM is in Ready
• livenessProbe: heartbeat-based (separate from FSM)

Safety Property

Ready ⇒ (recovery_complete ∧ invariants_checked ∧ services_registered)

Complexity Bounds

Recovery is O(|WAL| + |checkpoint|). The FSM tracks and exposes this to allow operators to configure appropriate probe timeouts.

Structs

BootBudgets

Time budget configuration for each boot phase

BootError

Error during boot

BootMetrics

Boot metrics for observability

BootOrchestrator

Boot orchestrator that coordinates the full boot sequence

BootStateMachine

Boot state machine with thread-safe state transitions

HealthStatus

Health status for probes and observability

PhaseProgress

Progress information for a boot phase

PreloadHints

Preload hints for deterministic warmup

Enums

BootPhase

Boot phase states (DFA transitions)

RecoveryMode

Recovery mode configuration