Network priority not implemented in docker-compose version 3.0

[ComBin]

I have docker-compose.yml v3.0 and i have issue from docker/compose#4645. Acording by documentations it is not implemented in 3.0. Is it planned to implement it? Or is there any reason why this feature was removed?

# docker-compose --version
docker-compose version 1.22.0, build f46880f

# docker --version
Docker version 18.06.1-ce, build e68fc7a

[kddubb]

+1 Interested in a response to this and when this will make it into v3?

[Daniel-Valentine]

+1 as well.

[fago]

Running into this as well.
That and having it to automatically add a network alias with the service name is problematic when using traefik. See https://forums.docker.com/t/multiple-networks-in-a-docker-compose-file-precedence/39071

[unglaublicherdude]

+1 from me as well. We have a Swarm with thousands of containers running and some networks are basically used in every deployed stack for most services.

We have sometimes the case, that the network where all the traffic is in (because of the problem mentioned here), just doesn't respond anymore when at the same time, the communication via the stacks default networks works just fine. This is a real issue for us. As Workaround we now prefix the default-networks of all stack with aaaa manually now.

[dpiquet]

+1 ! This is also an issue for us. Also using traefik.

[flikkes]

+1 ! as this is also an issue for us. We'd like to be able to rely on the order the networks IP addresses are added to /etc/hosts so we can use the first address as a default for certain configuration parameters. So being able to rely on the first network in the list being actually treated as the first one would be great!

[frgomes]

+1

[epica-shai]

+1

[OhMyVolk]

+1

[willopez]

Not having this is causing problems with my deployment of Reaction Commerce.

[thelittlefireman]

+1

[fhaferkorn]

+1

[jfellus]

I may be wrong but it seems to me that docker-compose's implementation doesn't make a difference between v2 and v3. Connections are indeed created from an OrderDict sorted by priority, no matter v2 or v3 is used (see https://github.com/docker/compose/blob/master/compose/network.py#L325, and PR docker/compose#5566 clearly show that v3 is ok since at least jan 2018)

Could anyone who know what happens next on the docker side explain why this priority isn't taken into account (BTW v2 and v3 priorities are equally ignored) ?
A rapid test https://gist.github.com/jfellus/cfee9efc1e8e1baf9d15314f16a46eca shows that network interfaces are allocated following lexical order of network names, despite any priority settings.

1. If I'm wrong, it would be great to make clear in the docs why v3 isn't displaying this cool feature, while v2 docs are still showing it albeit it doesn't really work... https://docs.docker.com/compose/compose-file/compose-file-v2/

2. If I'm right, could someone propose an addition to v3 docs to close misleading issues such as this one ? And eventually explain why it may have worked in the past (is it really the case ?)

thanks !

[pwatk]

+1 This is real pain. Please fix this.