Multiple Docker Compose files sharing a network

docker-compose.yaml

---
version: "3"
networks:
  local-dev:
    driver: bridge
---
version: "3"
services:
  shell:
    image: busybox
    stdin_open: true
    tty: true
    networks:
      - network_local-dev
networks:
  network_local-dev:
    external: true
---
version: "3"
services:
  server:
    image: nginx
    ports:
      - 8000:80
    networks:
      - network_local-dev
networks:
  network_local-dev:
    external: true

Split into three docker compose files:

cd network && docker-compose up -d && sleep 5
# nb4: docker network create network_local-dev --driver bridge
cd server && docker-compose up -d && sleep 5
cd shell && docker-compose run shell sh 

ping server