Add readme

README.md

@@ -1,2 +1,46 @@
-# prometheus-docker-discovery
-Prometheus Docker Discovery
+# Prometheus Docker Discovery
+
+This service exports [prometheus](https://prometheus.io/) metrics of various docker containers and volumes.
+
+## Metrics
+Currently supported metrics:
+- `docker_container_memory_usage_bytes` - Container memory usage (without caches)
+- `docker_container_cpu_usage_percent` - Container CPU usage percent (not divided by number of CPU cores
+- `docker_container_uptime_seconds` - Container uptime
+- `docker_container_rootfs_size_bytes` - Container rootfs size in bytes
+- `docker_container_disk_size_bytes` - Container size on disk in bytes
+- `docker_volume_size_bytes` - Size of a volume in bytes
+
+## Container Metrics Registration via Labels
+- Add `prometheus.job=<job-name>` label to the container to-be exported.
+- Optionally add other labels to be exported via `prometheus.labels.<label-name>=<label-value>`
+
+## Run Prometheus Docker Discovery
+```bash
+docker run -p 8000:8000 -v /var/run/docker.sock:/var/run/docker.sock iterait/prometheus-docker-discovery:master
+```
+
+Access http://localhost:8080/metrics This might take a while
+
+## Example docker-compose.yaml
+```yaml
+services:
+  db_prod:
+    image: postgres
+    labels:
+      - prometheus.job=db
+      - prometheus.labels.env=production
+
+  db_dev:
+    image: postgres
+    labels:
+      - prometheus.job=db
+      - prometheus.labels.env=dev
+
+  prometheus_docker_discovery:
+    image: iterait/prometheus-docker-discovery:master
+    ports:
+      - 8000:8000
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock
+```