How to specify Memory & CPU limit in docker compose version 3

Question

I am unable to specify CPU & memory for services specified in version 3 .

With version 2 it works fine with \"mem_limit\" & \"cpu_shares\" parameters under t

Answer 1

I know the topic is a bit old and seems stale, but anyway I was able to use these options:

    deploy:
      resources:
        limits:
          cpus: '0.001'
          memory: 50M

when using 3.7 version of docker-compose

What helped in my case, was using this command:

docker-compose --compatibility up

--compatibility flag stands for (taken from the documentation):

If set, Compose will attempt to convert deploy keys in v3 files to their non-Swarm equivalent

Think it's great, that I don't have to revert my docker-compose file back to v2.

Answer 2

deploy:
  resources:
    limits:
      cpus: '0.001'
      memory: 50M
    reservations:
      cpus: '0.0001'
      memory: 20M

More: https://docs.docker.com/compose/compose-file/#resources

In you specific case:

version: "3"
services:
  node:
    image: USER/Your-Pre-Built-Image
    environment:
      - VIRTUAL_HOST=localhost
    volumes:
      - logs:/app/out/
    command: ["npm","start"]
    cap_drop:
      - NET_ADMIN
      - SYS_ADMIN
    deploy:
      resources:
        limits:
          cpus: '0.001'
          memory: 50M
        reservations:
          cpus: '0.0001'
          memory: 20M

volumes:
  - logs

networks:
  default:
    driver: overlay

Note:

• Expose is not necessary, it will be exposed per default on your stack network.
• Images have to be pre-built. Build within v3 is not possible
• "Restart" is also deprecated. You can use restart under deploy with on-failure action
• You can use a standalone one node "swarm", v3 most improvements (if not all) are for swarm

Also Note: Networks in Swarm mode do not bridge. If you would like to connect internally only, you have to attach to the network. You can 1) specify an external network within an other compose file, or have to create the network with --attachable parameter (docker network create -d overlay My-Network --attachable) Otherwise you have to publish the port like this:

ports:
  - 80:80

Answer 3

Docker Compose does not support the deploy key. It's only respected when you use your version 3 YAML file in a Docker Stack.

This message is printed when you add the deploy key to you docker-compose.yml file and then run docker-compose up -d

WARNING: Some services (database) use the 'deploy' key, which will be ignored. Compose does not support 'deploy' configuration - use docker stack deploy to deploy to a swarm.

The documentation (https://docs.docker.com/compose/compose-file/#deploy) says:

Specify configuration related to the deployment and running of services. This only takes effect when deploying to a swarm with docker stack deploy, and is ignored by docker-compose up and docker-compose run.