Glossary

Core Cresco terms, in one place.

Term	Meaning
Agent	A leaf node — a JVM running the Cresco host + plugins, attached as a client to a regional controller's broker. Also, the identity of any node (region_agent).
Region / Regional controller	A controller that runs its own embedded ActiveMQ broker; the agents in its region attach to it. Federates up to a global.
Global / Global controller	The top of the hierarchy; federates regions (and other globals) together. Serves clients via wsapi.
Controller mode	A node's role: STANDALONE, AGENT, REGION, REGION_GLOBAL, or GLOBAL.
Controller	The fabric-brain module present on every node (messaging, discovery, security, health, db, data plane).
Plugin	An OSGi bundle providing functionality and exposing actions (e.g. sysinfo, wsapi, stunnel, repo).
MsgEvent	The unit of the control plane — a typed, addressed, routed message. See MsgEvent.
Action	A callable operation a plugin exposes, declared with @CrescoAction; invoked by sending a MsgEvent.
Capability inventory	The fabric-wide catalog of all actions (getcapabilityinventory).
Data plane	The pub/sub streaming channel over ActiveMQ topics (agent.event / region.event / global.event).
Control plane	The addressed MsgEvent channel over ActiveMQ queues.
MsgRouter	The controller component that makes the deterministic per-hop routing decision.
Federation / Network of brokers	Broker-to-broker ActiveMQ bridges that connect regions to globals (and globals to each other).
Bridge	A duplex, demand-forwarding ActiveMQ network connector between two brokers.
QoS tier	The priority class of a message: LIVENESS > CONTROL > TELEMETRY > BULK.
Discovery	Finding a parent controller (UDP broadcast or static TCP), gated by a tier join secret.
Join secret	The pre-shared discovery_secret_{agent,region,global} a node must present to join a tier.
Service key	cresco_service_key — the shared symmetric key authenticating agent traffic; must match fabric-wide.
CrescoIdentity	A node's identity tenant/region/agent(/uid), bound into its X.509 leaf DN (CN=agent, OU=region, O=tenant).
Regional CA	A region/global controller acting as a certificate authority, signing joiners' leaves — distributed trust (O(regions)).
Tenant	An isolation domain (O= in the cert DN). Multiple tenants can share one fabric; see Multi-Tenancy.
Tenant namespacing	Qualifying destinations T.<tenant>.<raw> so isolation is enforceable by a local prefix check at every broker.
Role	An authorization role: SUPERUSER (all tenants) or TENANT (own tenant only).
Health check	A Felix HealthCheck contributing a pass/fail verdict; run centrally by CrescoHealthExecutor.
MeasurementEngine	The per-bundle Micrometer registry; metrics are aggregated mesh-wide via getmetricinventory.
LinkMetrics	Per-edge network quality (RTT/jitter/throughput/backlog) in the netlink metric group.
wsapi	The WebSocket API plugin that bridges external clients to the fabric (wss://host:8282).
clientlib / pycrescolib	The external Java and Python client SDKs.
CADL / pipeline	A described application (a graph of plugins/edges) submitted to and orchestrated by the global controller.