fleetforge/docs/adrs/005-device-status.md

ADR-005: Device Status Calculation

Status

Accepted

Context

Devices report heartbeats at regular intervals. We need to determine online/offline status.

Decision

• Agent sends heartbeats every 30 seconds (configurable)
• Server marks device as online on each received heartbeat
• A background worker checks for stale devices every 60 seconds
• If last heartbeat is older than 2 minutes, device is marked offline
• If metrics show concerning values (disk > 90%), device is marked warning

Rationale

• Simple threshold-based status is reliable and easy to understand
• Status transitions are logged for audit purposes
• The threshold is configurable per-device or globally
• Future: more sophisticated health scoring

Consequences

• Status is computed server-side, not trusted from the agent
• The heartbeat interval affects status responsiveness
• Status changes generate audit events and can trigger alerts