3-Tier Architecture Deployment with Docker: Running Services (5)

In this post, we'll explore three different methods to run and manage the services we've set up, including the frontend, backend, database, and monitoring services.

1. Docker Command (run)

# Create networks
docker network create frontend_network
docker network create backend_network

# Run Nginx container
docker run -itd --name=internet_nginx --network frontend_network --restart always -p 80:80 example/nginx_proxy

# Run three frontend containers
docker run -itd --name=frontend1 --network frontend_network -p 3001:3000 example/frontend
docker run -itd --name=frontend2 --network frontend_network -p 3002:3000 example/frontend
docker run -itd --name=frontend3 --network frontend_network -p 3003:3000 example/frontend

# Run HAProxy container
docker run -itd --name=haproxy --network frontend_network --restart always example/haproxy
docker network connect backend_network haproxy

# Run MongoDB container
docker run -itd --name=mongodb --network backend_network -p 27017:27017 example/mongodb

# Run three backend containers with port mappings
docker run -itd --name=backend1 --network backend_network -p 8081:8080 example/backend
docker run -itd --name=backend2 --network backend_network -p 8082:8080 example/backend
docker run -itd --name=backend3 --network backend_network -p 8083:8080 example/backend

Explanation:

• docker network create: Creates networks to allow communication between containers.

• docker run: Launches each container with specific settings.

  • -itd: Runs the container in interactive mode, detached (in the background).

  • --name: Assigns a name to the container.

  • --network: Connects the container to a specified network.

  • --restart always: Ensures the container restarts automatically if it stops.

2. Docker Compose

docker-compose.yml

version: "3.8"

services:
  internet_nginx:
    image: example/nginx_proxy
    container_name: internet_proxy
    restart: always
    networks:
      - frontend-net
    ports:
      - "80:80"

  frontend_service:
    image: example/frontend
    restart: always
    networks:
      - frontend-net
    ports:
      - "3001-3003:3000"
    deploy:
      mode: replicated
      replicas: 3

  haproxy:
    image: example/haproxy
    container_name: haproxy
    restart: always
    networks:
      - frontend-net
      - backend-net

  backend_service:
    image: example/backend
    restart: always
    networks:
      - backend-net
    deploy:
      mode: replicated
      replicas: 3

  mongodb:
    image: example/mongodb
    container_name: mongodb
    restart: always
    networks:
      - backend-net
    ports:
      - "27017:27017"
    volumes:
      - /home/user/acswikicompose/mongodbData:/data/db

  prometheus:
    image: prom/prometheus:latest
    container_name: prometheus
    command:
      - '--config.file=/etc/prometheus/prometheus.yml'
      - '--storage.tsdb.path=/prometheus'
    volumes:
      - ./prometheus/prometheus.yml:/etc/prometheus/prometheus.yml
    ports:
      - "19090:9090"
    networks:
      - frontend-net
      - backend-net

  node-exporter:
    image: prom/node-exporter
    container_name: node-exporter
    ports:
      - "9100:9100"
    networks:
      - frontend-net
      - backend-net
    command:
      - '--no-collector.powersupplyclass'

  cadvisor:
    image: google/cadvisor:latest
    container_name: cadvisor
    ports:
      - "9559:8080"
    volumes:
      - /:/rootfs:ro
      - /var/run:/var/run:rw
      - /sys:/sys:ro
      - /var/lib/docker/:/var/lib/docker:ro
    networks:
      - frontend-net
      - backend-net

  grafana:
    image: grafana/grafana:latest
    container_name: grafana
    ports:
      - "13000:3000"
    volumes:
      - ./grafana/datasource.yml:/etc/grafana/provisioning/datasources/datasource.yml
    environment:
      - GF_AUTH_ANONYMOUS_ORG_ROLE=Admin
      - GF_SECURITY_ADMIN_PASSWORD=pass123#
    networks:
      - frontend-net
      - backend-net

  portainer:
    image: portainer/portainer-ce
    container_name: portainer
    privileged: true
    ports:
      - "29000:9000"
    volumes:
      - portainer_data:/data
      - /var/run/docker.sock:/var/run/docker.sock
    networks:
      - frontend-net
      - backend-net

networks:
  backend-net:
    driver: bridge
    ipam:
      driver: default
      config:
        - subnet: "172.20.0.0/16"
          gateway: "172.20.0.1"
  frontend-net:
    driver: bridge
    ipam:
      driver: default
      config:
        - subnet: "172.21.0.0/16"
          gateway: "172.21.0.1"

volumes:
  portainer_data:

Explanation:

• version: Specifies the Docker Compose file format version.

• services: Defines multiple container services.

• networks: Connects containers to specific networks.

• ports: Maps container ports to host ports.

• volumes: Mounts host directories to containers for data persistence.

3. Docker Stack

docker-stack.yml

version: "3.8"

services:
  internet_nginx:
    image: example/nginx_proxy
    networks:
      - frontend-net
    ports:
      - "80:80"
    depends_on:
      - frontend_service

  frontend_service:
    image: example/frontend
    networks:
      - frontend-net
    ports:
      - "3001-3003:3000"
    depends_on:
      - haproxy
    deploy:
      mode: replicated
      replicas: 3

  haproxy:
    image: example/haproxy
    networks:
      - frontend-net
      - backend-net
    depends_on:
      - backend_service

  backend_service:
    image: example/backend
    networks:
      - backend-net
    ports:
      - "8081-8083:8080"
    deploy:
      mode: replicated
      replicas: 3

  mongodb:
    image: example/mongodb
    networks:
      - backend-net
    ports:
      - "27017:27017"

  grafana:
    image: grafana/grafana:latest
    ports:
      - "13000:3000"
    volumes:
      - ./grafana/datasource.yml:/etc/grafana/provisioning/datasources/datasource.yml
    environment:
      - GF_AUTH_ANONYMOUS_ORG_ROLE=Admin
      - GF_SECURITY_ADMIN_PASSWORD=pass123#
    networks:
      - monitor-net
    depends_on:
      - prometheus

  prometheus:
    image: prom/prometheus:latest
    command:
      - '--config.file=/etc/prometheus/prometheus.yml'
      - '--storage.tsdb.path=/prometheus'
      - '--web.console.libraries=/usr/share/prometheus/console_libraries'
      - '--web.console.templates=/usr/share/prometheus/consoles'
    volumes:
      - ./prometheus/prometheus.yml:/etc/prometheus/prometheus.yml

Explanation:

• deploy: Configures deployment settings for Docker Swarm mode.

• mode: Sets deployment mode (e.g., replicated, global).

• depends_on: Ensures services start in the correct order.

Summary of Execution Methods

• Docker Command (run): Manually starts each container and network, giving fine-grained control over each service.

• Docker Compose: Simplifies running multiple containers with a single command, ideal for development and small setups.

• Docker Stack: Deploys containers in a Swarm cluster, suitable for production environments with scaling needs.