Description

I originally asked this on SO without resolution, so I assume it's not possible, and hence this feature request.

Description

I have a number of services in a docker stack, where some are started manually only.

docker-compose.yml:

services:

  other:
    # ...

  app:
    # ...
    depends_on:
     - postgres
    deploy:
      replicas: 0

  postgres:
    # ...
    deploy:
      replicas: 0

  pgadmin:
    # ...
    deploy:
      replicas: 0

I can start app and postgres like this:

docker compose up -d --scale app=1 --scale postgres=1

If I then start pgadmin:

docker compose up -d --scale pgadmin=1

...it will stop app and postgres and then start pgadmin. I don't want to stop them.

I assume I can't scale a service without impacting existing services. The only reason I can imagine is the swarm reasoning: you tell compose what state you want, and it scales services to get to that state. BUT: 1) I'm not using swarm, and 2) why should that be the rule?

This is a very common use case, and the only workaround is complex hard-to-maintain scripts.

Please allow us to scale services without side effects. For example via a --scale-independently switch:

docker compose up -d --scale pgadmin=1 --scale-independently

Docker would realise that other services are already running, so that command would be equivalent to:

docker compose up -d --scale app=1 --scale postgres=1 --scale pgadmin=1