Concepts

The ideas behind Barista, ordered from workload identity to platform operation. Unless a section is marked Planned, these pages describe the implemented surface.

• Sessions — direct instance ids, fleet names, and the single-writer model.
• Sleep and wake — TTL, scheduled wake, explicit resume, and the planned request edge.
• Snapshots — captured state, restore keys, retained points, and storage tiers.
• Lifecycle and operations — the state machine, journaled mutations, idempotency, and events.
• Capabilities and tiers — implemented runtimes, deferred tiers, and explicit degradation.
• Fleet coordination — one name and one owner across nodes, without a control-plane service.
• Networking and egress — current node access and capability-gated egress, plus the planned gateway.
• The guest agent — the injected daemon and restore duties.

In one paragraph

A direct client addresses an instance by ULID. A fleet client declares a session name in a bucket, and exactly one node acquires it. Every mutation is a journaled operation safe to follow and retry through Contract A. On a memory-capable runtime, Pause turns memory and disk into a local snapshot and releases the sandbox; Resume restores the same process. Command and scheduled wake work today. Transparent wake on traffic belongs to the planned gateway.