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EventBus Configuration

The EventBus provides reliable message delivery between EventSource and Sensor.

NATS with Persistence

For production, use NATS with persistence enabled:

apiVersion: argoproj.io/v1alpha1
kind: EventBus
metadata:
  name: default
  namespace: argo-events
spec:
  nats:
    native:
      replicas: 3
      auth: token
      persistence:
        storageClassName: standard-rwo
        accessMode: ReadWriteOnce
        volumeSize: 10Gi
      antiAffinity: true
      maxAge: 72h

Why persistence matters:

Feature Without Persistence With Persistence
Pod restart Events lost Events buffered
Network partition Silent drops Retry on reconnect
Burst handling Overflow drops Queue to disk

Default Configuration Risk

Default Jetstream configurations optimize for simplicity. Events missed during pod restarts are gone forever. Production deployments need persistence.

Tuning Parameters

spec:
  nats:
    native:
      maxPayload: 1048576  # 1MB max message size
      maxMsgs: 10000       # 10k message buffer
      maxAge: 72h          # Retain messages for 72 hours

JetStream EventBus (Production)

For high-throughput production workloads, use JetStream with explicit resource limits:

apiVersion: argoproj.io/v1alpha1
kind: EventBus
metadata:
  name: default
  namespace: argo-events
spec:
  jetstream:
    version: 2.10.10
    replicas: 3
    maxPayload: "0"  # Unlimited payload size
    containerTemplate:
      resources:
        requests:
          cpu: 200m
          memory: 600Mi
        limits:
          cpu: 200m
          memory: 600Mi

JetStream vs NATS Native:

Feature NATS Native JetStream
Message persistence Manual config Built-in
Stream management Basic Advanced (retention, limits)
Consumer groups Limited Full support
Resource efficiency Lower overhead Higher throughput

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