fix: use 2 instances with load-balancer

config/nginx.conf

@@ -0,0 +1,16 @@
+upstream service {
+    server api:8080;
+    server api-backup:8081;
+}
+
+server {
+    listen 80;
+
+    location / {
+        proxy_pass http://service;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+    }
+}

config/prometheus.yml

@@ -5,4 +5,4 @@ global:
 scrape_configs:
   - job_name: 'api'
     static_configs:
-      - targets: ['api:8080']
+      - targets: ['api:8080', 'api-backup:8081']

docker-compose.yml

@@ -1,12 +1,22 @@
 version: "3"
 services:
+  # Server instances
   api:
     build:
       context: .
       dockerfile: ./docker/api.Dockerfile
     ports:
       - 8080:8080
     container_name: api
+  api-backup:
+    build:
+      context: .
+      dockerfile: ./docker/api.Dockerfile
+    ports:
+      - 8081:8080
+    container_name: api-backup
+
+  # Observability
   prometheus:
     image: prom/prometheus:latest
     container_name: prometheus
@@ -25,3 +35,15 @@ services:
       - GF_SECURITY_ADMIN_PASSWORD=${GRAFANA_PASSWORD}
     depends_on:
       - prometheus
+
+  # Load balancer
+  nginx:
+    image: nginx:alpine
+    container_name: nginx
+    ports:
+      - "80:80"
+    volumes:
+      - ./config/nginx.conf:/etc/nginx/nginx.conf
+    depends_on:
+      - api
+      - api-backup