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

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

Answer 1

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.

Answer 2

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