docker-swarm

docker-compose.yml

version: '3'

services:
  webapp:
   image: YOUR_PHP
   ports:
     - 12345:12345
   deploy:
     replicas: 10
     restart_policy:
       max_attempts: 3
       condition: on-failure       
     update_config:
       parallelism: 2
       delay: 1m
   networks: 
    - balance 
  
  proxy:
    image: YOUR_NGINX
    ports:
      - 80:80
    depends_on:
      - webapp
    deploy:
      placement:
        constraints: [node.role == manager]
    networks: 
      - balance

networks:
  balance:
    driver: overlay

nginx.conf

http {
    upstream myCluster {
        server IP_1:1324;
        server IP_2:1234;
        server IP_n:1234;
    }

    server {
        listen 80;
        location / {
            proxy_pass http://myCluster;
        }
    }
}

nginx.Dockerfile

FROM nginx
COPY nginx.conf /etc/nginx/conf.d/
EXPOSE 80

php.Dockerfile

FROM php:cli-alpine
RUN echo "<?php echo gethostname() . ' - ' . gethostbyname(gethostname()) . ' - Version 1';" > index.php
EXPOSE 12345
CMD php -S 0.0.0.0:12345