How to use host network for docker compose?

You are mixing options that are invalid on either compose and swarm deployments.

If you are deploying with docker-compose up then your compose file should be like this:

version: "3"
services:
  web:
    image: conatinera:latest
    network_mode: "host"        
    restart: on-failure

Te options deploy is ignored on compose mode and the ports option is ignored when using host mode networking. I recommend to don’t use host mode networking and use a reverse proxy in another container to balance your scaled containers.

(Feel free to ignore this part of the answer as you clarified that you aren’t using swarm deployments).

If you are using swarm deployment then your compose file should be like this:

version: "3.4"
services:
  web:
    image: conatinera:latest
    deploy:
      replicas: 1
      resources:
        limits:
          cpus: "0.5"
          memory: 4G 
      restart_policy:
        condition: on-failure
    networks:
      - host

networks:
  host:
    name: host
    external: true

Again, published ports and host mode networking do not mix. Also is probably that your scaling will fail because all the containers will try to bind to the same port. I recommend to don’t use host mode networking and let docker load balance your replicas.