smpp-connector — Deployment Topology

Status: populated | Last updated: 2026-04-18

1. Deployment Model

smpp-connector can be deployed in two topologies:

Option A (current): Single Deployment manages connections to all assigned operators via an in-process session map. Operator assignment is via OPERATOR_IDS environment variable.

Option B (future): One Deployment per operator for complete isolation. Chosen when operator TPS requirements or failure domains require strict separation.

The initial production deployment uses Option A with 2 replicas.

Note: Only one replica per operator maintains an active SMPP session at a time. The second replica acts as a hot standby. NATS consumer group ensures messages are only processed by the active session holder.

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2. Kubernetes Resources

Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: smpp-connector
  namespace: sms-gateway
  labels:
    app: smpp-connector
spec:
  replicas: 2
  selector:
    matchLabels:
      app: smpp-connector
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  template:
    metadata:
      labels:
        app: smpp-connector
      annotations:
        prometheus.io/scrape: "true"
        prometheus.io/port: "3001"
    spec:
      serviceAccountName: smpp-connector
      containers:
        - name: smpp-connector
          image: ghcr.io/ghasitech/smpp-connector:1.0.0
          ports:
            - containerPort: 3001
              name: http-mgmt
          env:
            - name: OPERATOR_IDS
              valueFrom:
                configMapKeyRef:
                  name: smpp-connector-config
                  key: operator-ids
            - name: DATABASE_URL
              valueFrom:
                secretKeyRef:
                  name: smpp-connector-secrets
                  key: database-url
            - name: REDIS_URL
              valueFrom:
                secretKeyRef:
                  name: smpp-connector-secrets
                  key: redis-url
            - name: NATS_URL
              value: "nats://nats.sms-gateway.svc.cluster.local:4222"
            - name: OPERATOR_MGMT_URL
              value: "https://operator-management-service.sms-gateway.svc.cluster.local:3000"
            - name: LOG_LEVEL
              value: "info"
          volumeMounts:
            - name: nats-creds
              mountPath: /run/secrets/nats
              readOnly: true
            - name: tls-certs
              mountPath: /run/secrets/tls
              readOnly: true
          resources:
            requests:
              cpu: "500m"
              memory: "512Mi"
            limits:
              cpu: "2000m"
              memory: "1Gi"
          livenessProbe:
            httpGet:
              path: /health
              port: 3001
            initialDelaySeconds: 15
            periodSeconds: 20
          readinessProbe:
            httpGet:
              path: /ready
              port: 3001
            initialDelaySeconds: 10
            periodSeconds: 15
      volumes:
        - name: nats-creds
          secret:
            secretName: smpp-connector-nats-creds
        - name: tls-certs
          secret:
            secretName: smpp-connector-tls

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3. Network Topology

[NATS JetStream] ──► smpp-connector (consumer: smpp.operator.*)
                 ◄── smpp-connector (publisher: sms.dlr.inbound, operator.health)

[smpp-connector] ──────── TCP :2775 ──────────► [MNO SMPP Server]
                  (egress whitelisted in NetworkPolicy + MNO firewall)

[smpp-connector] ── HTTPS :3000 ──► [operator-management-service] (credentials fetch)
[smpp-connector] ── TCP :5432  ──► [PostgreSQL smpp schema]
[smpp-connector] ── TCP :6379  ──► [Redis TPS counters]

smpp-connector has no inbound TCP ports except port 3001 (management) accessible only from Prometheus within the cluster.

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4. Environments

Environment	Replicas	SMPP Target
development	1	Local mock SMPP server (Docker Compose)
staging	1	MNO staging/test SMPP endpoint
production	2 (active+standby per operator group)	MNO production SMPP endpoint