How to apply the same volumes to multiple docker compose services?

Question

Let's suppose there are two services and they have several volumes defined. But most of those volumes are used on both services:

version: '3'
services:
  service1:
    image: node:lts-alpine
    working_dir: /
    volumes:
      - ./package.json:/package.json
      - ./tsconfig.json:/tsconfig.json
      - ./packages:/packages
      - ./node_modules:/node_modules
      - ./services/service1:/services/service1
    command: yarn service1:start

  service2:
    image: node:lts-alpine
    working_dir: /
    volumes:
      - ./package.json:/package.json
      - ./tsconfig.json:/tsconfig.json
      - ./packages:/packages
      - ./node_modules:/node_modules
      - ./services/service2:/services/service2
    command: yarn service2:start

Is there a way to prevent this duplication?

I would love to do something like this:

version: '3'
services:
  service1:
    image: node:lts-alpine
    working_dir: /
    volumes:
      - myVolumeList
      - ./services/service1:/services/service1
    command: yarn start

  service2:
    image: node:lts-alpine
    working_dir: /
    volumes:
      - myVolumeList
      - ./services/service2:/services/service2
    command: yarn start

myVolumeList:
  - ./package.json:/package.json
  - ./tsconfig.json:/tsconfig.json
  - ./packages:/packages
  - ./node_modules:/node_modules

Edit: I use docker compose for local development only. Volumes are great for me because changing source code files will automatically restart my services. Thus copying files once isn't enough

score 1 · Answer 1 · answered May 01 '20 at 18:02

The code for your application should generally be in a Docker image. You can launch multiple containers from the same image, possibly with different command:. For example, you might write a Dockerfile like:

FROM node:lts-alpine
WORKDIR /app
COPY package.json yarn.lock ./
RUN yarn install
COPY ./ ./
CMD yarn start

Having described this image, you can reference it in the docker-compose.yml, overriding the command: for each service:

version: '3'
services:
  service1:
    build: .
    command: 'yarn service1:start'
  service2:
    build: .
    command: 'yarn service2:start'

(Compose will probably try to build a separate image for each service, but because of Docker layer caching, "building" the service2 image will run very quickly and wind up with a second tag on the same image.)

This setup needs no bind-mounts at all, and if you push the built images to a Docker registry, you can run them on a system without the application code or even Node available.

That makes sense. But I use docker compose for local dev only. I use volumes because after changing source code the services will automatically restart. Thus copying the files isn't enough for (I should have mentioned this in the question) — Florian Ludewig, May 01 '20 at 18:46

leandrosantos89 · Answer 2 · 2020-05-01T20:50:50.140

Natively, you can do:

Maybe this solve your problem.

version: "3"

services:
  srv1:
    image: someimage
    volumes:
      - data:/data
  srv2:
    image: someimage
    volumes:
      - data:/data

volumes:
  data:

There's a plugin - https://github.com/MatchbookLab/local-persist (read it before use!)- that let you change the volume mountpoint.

Basicaly, install it: curl -fsSL https://raw.githubusercontent.com/MatchbookLab/local-persist/master/scripts/install.sh | sudo bash

Then create a volume: docker volume create -d local-persist -o mountpoint=/data/images --name=images

Then use as many containers as you want:

docker run -d -v images:/path/to/images/on/one/ one
docker run -d -v images:/path/to/images/on/two/ two

If you whant to use docker-compose, there's a example:

version: '3'

services:
  one:
    image: alpine
    working_dir: /one/
    command: sleep 600
    volumes:
      - data:/one/

  two:
    image: alpine
    working_dir: /two/
    command: sleep 600
    volumes:
      - data:/two/

volumes:
  data:
    driver: local-persist
    driver_opts:
      mountpoint: /data/local-persist/data

Almost the same question here: docker volume custom mount point

This only work on docker-compose version '2':

version: '2'
services:

  srv1:
    image: sometag
    volumes_from:
      - data

  srv2:
    image: sometag
    volumes_from:
      - data

  data:
    image: sometag
    volumes:
      - ./code-in-host:/code

Hmm interesting! I might try it as a last resort, but I would like to stick to native docker compose features — Florian Ludewig, May 01 '20 at 18:47
@FlorianLudewig Yes, I understand. There's another option too: data-only containers, like this -> https://docs.docker.com/storage/volumes/#backup-restore-or-migrate-data-volumes. — leandrosantos89, May 01 '20 at 19:44

How to apply the same volumes to multiple docker compose services?

2 Answers2