Global/default override for all services

[durera]

What I want to do is separate my environment specific tweaks into an override.yml, nothing fancy there ... however my overrides will be exactly the same for every single service deployed & I want to avoid having to write out the same override for every single service (and continually add new sections to the override as new services are introduced).

Instead I would like to create one definition that says "apply to this override to every single service". Does such a concept exist already that I am perhaps missing?

Example ...

docker-compose.yml:

  aservice:
    image: whatever1
    environment:
      FOO: BAR

another docker-compose.yml:

  anotherservice:
    image: whatever2

my docker-compose.override.yml:

  <magickeyword>:
    environment:
      FLIBBLE: flobble
    dns:
      - server1
      - server2

Now, every service deployed would have DNS server1 & server2 and the environment variable FLIBBLE.

I realise I could do this if all services were extending the same base service as I could apply the override to that, but is there anyway to set global/default override without a common extension?

At the moment I have a hack that involves a generated override scanning for any defined services and generate the override file on the fly, but it seems like a use case that I can't be the first person to run into so wondered if perhaps I have just missed the obvious solution to this in compose.

[shin-]

You could just have a base.yml file in each project folder with a base service containing just your environment key, then have each service extend the base service.

[saml]

This is no longer a good solution given that extends: is removed in 3.x moby/moby#31101

[shin-]

@saml check out #5140