Il clustering connette più nodi RabbitMQ in un unico broker logico — per scalabilità e (con code replicate) alta disponibilità. Comprendere il clustering e le sue sfumature è importante per scalare e operare RabbitMQ in modo affidabile.
Che cos'è un cluster
A RabbitMQ CLUSTER = multiple nodes acting as ONE logical broker:
→ nodes share METADATA (queue/exchange definitions, bindings, users, vhosts) across the cluster
→ clients can connect to any node; load is distributed across nodes
→ scales connection/channel capacity and distributes load
Code in un cluster (una sfumatura importante)
⚠️ By default, a queue's DATA lives on ONE node (the node where it was declared):
→ other nodes know about the queue (metadata) but route to the owning node
→ if that node FAILS → the queue (and its messages) is UNAVAILABLE
→ so CLUSTERING ALONE does NOT make queues highly available!
→ for HA → use REPLICATED queues (QUORUM QUEUES) that replicate data across nodes
