feat: add Prometheus configuration and enable metrics scraping for Traefik

swarm/core.yml

@@ -162,6 +162,11 @@ services:
       - --log.level=INFO
       # Enable the Dashboard and API
       - --api=true
+      # Enable Prometheus metrics for scraping by Prometheus
+      - --metrics.prometheus=true
+      - --metrics.prometheus.buckets=0.1,0.3,1.2,5.0
+      - --metrics.prometheus.addEntryPointsLabels=true
+      - --metrics.prometheus.addServicesLabels=true
     networks:
       # Use the public network created to be shared between Traefik and
       # any other service that needs to be publicly available with HTTPS

swarm/prometheus.yml

@@ -1,6 +1,10 @@
 volumes:
   prometheus_data: {}
 
+configs:
+  prometheus_config:
+    file: ./prometheus/prometheus.yml
+
 networks:
   traefik-public:
     external: true
@@ -17,8 +21,10 @@ services:
       - '--web.enable-lifecycle'
     volumes:
       - prometheus_data:/prometheus
-      - /var/data/prometheus/prometheus.yml:/etc/prometheus/prometheus.yml:ro
       - /var/data/prometheus/rules:/etc/prometheus/rules:ro
+    configs:
+      - source: prometheus_config
+        target: /etc/prometheus/prometheus.yml
     networks:
       - traefik-public
     deploy:

swarm/prometheus/prometheus.yml

@@ -0,0 +1,19 @@
+# Prometheus configuration for the Swarm stack.
+# Mounted into the Prometheus container as a Docker config.
+global:
+  scrape_interval: 15s
+  evaluation_interval: 15s
+
+scrape_configs:
+  # Scrape Prometheus itself
+  - job_name: 'prometheus'
+    static_configs:
+      - targets: ['localhost:9090']
+
+  # Scrape Traefik Prometheus metrics
+  # Both services are on the traefik-public overlay network,
+  # so 'traefik' resolves via Swarm DNS.
+  - job_name: 'traefik'
+    static_configs:
+      - targets: ['traefik:8080']
+    metrics_path: /metrics