Simple Prometheus Docker Compose setup

docker-compose.yml

version: '3.7'

volumes:
    prometheus_data: {}

# Setup:
# The app root directory contains an "etc" subdir with the config files required by all containers.
# Docker Compose creates an internal network for all containers so they can call each other by name.

services:
  # Prometheus runs on its default port 9090. It's configured to scrape data from http://exporter:9091
  # and send alerts to http://alertmanager:9093.
  prometheus:
    image: prom/prometheus:v2.14.0
    ports:
      - "9090:9090" # Expose Prometheus port
    volumes:
      - ./etc:/etc/myapp
      - prometheus_data:/prometheus
    command:
      - '--config.file=/etc/myapp/prometheus.yml'
      - '--storage.tsdb.path=/prometheus'
    depends_on:
      # Make sure exporter and alertmanager are up before prometheus.
      - exporter
      - alertmanager
    restart: always

  # Alertmanager listens for incoming alerts on port 9093 and sends webhooks to http://sender:9094.
  alertmanager:
    image: prom/alertmanager:v0.19.0
    ports:
      - "9093:9093" # Expose Alertmanager port
    volumes:
      - ./etc:/etc/myapp
    command:
      - '--config.file=/etc/myapp/alertmanager.yml'
      - '--storage.path=/alertmanager'
    depends_on:
      - sender  # Make sure the sender is up.
    restart: always

  # A custom Exporter. It reads data from an external source and makes it available
  # to Prometheus on port 9091.
  exporter:
    # The exporter is in a subdirectory called MyExporter, complete with a Dockerfile.
    build: MyExporter
    ports:
      - "9091"  # No need to expose the exporter, only Prometheus needs it.
    volumes:
      - ./etc:/etc/myapp  # Config is read from /etc/myapp/exporter.yml.
    restart: always

  # A custom webhook-based alert sender. Listens on port 9094.
  sender:
    # The exporter is in a subdirectory called Sender, complete with a Dockerfile.
    build: Sender
    ports:
      - "9094"  # Like exporter, it only needs to be available internally.
    volumes:
      - ./etc:/etc/myapp  # Config is read from /etc/myapp/sender.yml.
    restart: always