Population Health Service — Deployment Topology

Status: populated Owner: TBD Last updated: 2026-04-18 Companion: Service Template · 03 platform-services

1. Runtime

Property	Value
Runtime	Node.js 22 / NestJS 11
Language	TypeScript 5.x
Package	@ghasi/service-population-health
Container image	ghasi/population-health-service:<tag>
Exposed port	3030
Health check	GET /health (liveness + readiness)

2. Replicas and Scaling

Environment	API replicas	Worker replicas	Scaling trigger
Development	1	1	—
Staging	2	2	—
Production	3–6	2–4	CPU > 70% OR queue depth > 100

Worker processes handle cohort refresh, risk scoring, quality metric computation, HMIS export, and de-identification jobs via NATS JetStream pull consumers.

3. Dependencies

4. Data Residency and Regions

Environment	Region	Notes
Production (Afghanistan)	af-central-1 (MoPH sovereign cloud)	PostgreSQL + object storage must remain in-country
Staging	af-staging	Same region, isolated namespace
DR	af-central-2 (if available)	Async replication; RTO 4h, RPO 1h

5. Kubernetes Configuration Sketch

apiVersion: apps/v1
kind: Deployment
metadata:
  name: population-health-service
spec:
  replicas: 3
  template:
    spec:
      containers:
        - name: api
          image: ghasi/population-health-service:latest
          ports:
            - containerPort: 3030
          resources:
            requests: { cpu: "250m", memory: "512Mi" }
            limits:   { cpu: "1000m", memory: "1.5Gi" }
          env:
            - name: DATABASE_URL
              valueFrom:
                secretKeyRef: { name: pophealth-db-secret, key: url }
            - name: NATS_URL
              value: nats://nats-cluster:4222
            - name: DHIS2_BASE_URL
              valueFrom:
                configMapKeyRef: { name: pophealth-config, key: dhis2_url }

6. NATS Stream Bootstrap

nats stream add POPULATION_HEALTH \
  --subjects "population_health.>" \
  --storage file \
  --replicas 3 \
  --retention limits \
  --max-age 14d \
  --max-msg-size 131072