DLR Processor — Deployment Topology

Status: populated Owner: Platform Engineering Last updated: 2026-04-18 Companion: LOCAL_DEV_SETUP · OBSERVABILITY

1. Kubernetes Workload

apiVersion: apps/v1
kind: Deployment
metadata:
  name: dlr-processor
  namespace: sms-gateway
spec:
  replicas: 3
  selector:
    matchLabels:
      app: dlr-processor
  template:
    spec:
      containers:
        - name: dlr-processor
          image: ghasi/dlr-processor:latest
          resources:
            requests:
              cpu: "250m"
              memory: "256Mi"
            limits:
              cpu: "500m"
              memory: "512Mi"
          livenessProbe:
            httpGet: { path: /health, port: 3000 }
            initialDelaySeconds: 10
            periodSeconds: 15
          readinessProbe:
            httpGet: { path: /ready, port: 3000 }
            initialDelaySeconds: 5
            periodSeconds: 10
          envFrom:
            - secretRef: { name: dlr-processor-secrets }
            - configMapRef: { name: dlr-processor-config }

2. Horizontal Pod Autoscaler

apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: dlr-processor-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: dlr-processor
  minReplicas: 3
  maxReplicas: 10
  metrics:
    - type: External
      external:
        metric:
          name: nats_consumer_pending_messages
          selector:
            matchLabels:
              consumer: dlr-processor
        target:
          type: AverageValue
          averageValue: "500"

Scale-out trigger: NATS dlr-processor consumer pending message count > 500 per replica.

3. Network Topology

[NATS JetStream Cluster] ──(internal)──► dlr-processor pods
dlr-processor pods ──(internal PG)────► PostgreSQL (orch + dlr schemas)
dlr-processor pods ──(internal NATS)──► billing.events, webhook.dispatch, sms.dlr.unmatched

No inbound internet traffic. No Kong route. No public endpoint.

4. Environment Variables

Variable	Description	Example
NATS_URL	NATS server URL(s)	nats://nats:4222
NATS_STREAM_DLR	JetStream stream name	SMS_DLR
DATABASE_URL	PostgreSQL connection string	postgresql://dlr_svc:***@pg:5432/ghasi
DB_POOL_MIN	Min connection pool size	5
DB_POOL_MAX	Max connection pool size	20
OTEL_EXPORTER_OTLP_ENDPOINT	OTLP collector	http://otel-collector:4318
LOG_LEVEL	Pino log level	info
PORT	HTTP probe port	3000

5. Multi-Region Considerations

In active-active multi-region deployments:

• Each region runs its own dlr-processor replica set.
• NATS geo-replicated stream ensures each region's processors see all DLRs.
• PostgreSQL cross-region writes must route to the primary via service mesh (Consul Connect or Linkerd).
• Orphan reconciliation job is single-region (runs in primary region only).

6. Secrets Management

Secrets stored in HashiCorp Vault; injected via Vault Agent sidecar as Kubernetes Secrets at pod start. Rotation: 90-day automated schedule.