Study Lab
local appVango

Glossary

Concrete definitions with the common trap for each term.

Allocation

Runtime

A concrete running instance of a deployment artifact in a region/cell.

Common trap

Treating it as the deployment or source of route truth.

Artifact

Deploy

An immutable build output with manifest, digest, source, process, asset, and validation facts.

Common trap

Rebuilding mutable source during promotion.

Broadcast backend

Runtime services

A fanout service for live shared/global state updates across allocations.

Common trap

Using it as product database truth.

Cell

Topology

The unit of regional runtime and data-plane isolation.

Common trap

Hardcoding one launch cell into public identity.

Cold deploy

Deploy

A deploy whose persisted Vango state is not warm-compatible.

Common trap

Presenting it as a normal zero-risk promotion.

Compare-and-swap

Distributed systems

A conditional write that succeeds only if the predecessor version is still current.

Common trap

Letting stale promotion workers overwrite newer route ownership.

Drain

Runtime

A no-new-work posture that lets existing sessions or jobs finish before stop.

Common trap

Claiming sessions moved when they are still attached to the old allocation.

Durable consumer

NATS

A JetStream consumer with a remembered cursor for replay and recovery.

Common trap

Assuming all subscribers are always online.

Idempotency key

API

A client or operation key that makes retry attach to the original mutation.

Common trap

Retrying mutation requests and creating duplicate resources.

JetStream

NATS

NATS durable stream layer with retention, consumers, replay, and acknowledgements.

Common trap

Treating the event stream as the authoritative database.

RPO

Recovery

The amount of data loss a recovery plan permits.

Common trap

Confusing it with downtime.

RTO

Recovery

The target time to restore service after failure.

Common trap

Confusing it with data loss.

Route epoch

Routing

A monotonic route ownership version used to reject stale updates.

Common trap

Routing by latest healthy backend instead of route owner authority.

Route owner

Routing

The control-plane object that binds a route key to deployment/artifact/region/cell authority.

Common trap

Confusing it with allocation selection.

Session store

Runtime services

Durable storage for resumable Vango session state.

Common trap

Assuming it serializes an entire Go process.

Warm deploy

Deploy

A deploy whose persisted Vango state remains compatible enough for resume policy.

Common trap

Assuming warm deploy proves database rollback safety.