Implement dns_opt in version 3

[ylavoie]

Even with version 3, dns_opt is still required to pass specific options like ndots and get around dns problems

[shin-]

Please submit v3 feature requests on the docker/cli repo.

[maciejmatuszak]

Hi @shin- the docker cli already implements the --dns-opt or --dns-option. The docker-compose dns-opt is in V2 https://docs.docker.com/compose/compose-file/compose-file-v2/#dns_opt but is not V3. What would it take to implement/port it from V2 to V3?

[shin-]

The v3 format is controlled and updated on the docker/cli repo (as the primary intention of the v3 format is to work with docker stack deploy), so it needs to be proposed there first before we can port the change back into the docker-compose codebase. For the change to be accepted in docker/cli, it would probably require an implementation of the feature for Swarm services (which seems to exist at the API level, so shouldn't be too daunting to add).

[ps-jay]

Hi @shin-,

I'm trying to understand what you mean by the "v3 format is controlled and updated on the docker/cli repo".

What file(s), should I look at in docker/cli to see what is (or should be) supported by compose?

From what I can see, --dns-option is already in the docker run CLI (see: docker/cli@ebacbb5), but it's not available in compose.

Should we raise an issue in docker/cli that dns_option is not also available in the v3 format?

[shin-]

Hi @shin-,

I'm trying to understand what you mean by the "v3 format is controlled and updated on the docker/cli repo".

What file(s), should I look at in docker/cli to see what is (or should be) supported by compose?

https://github.com/docker/cli/tree/master/cli/compose/schema/data

From what I can see, --dns-option is already in the docker run CLI (see: docker/cli@ebacbb5), but it's not available in compose.

Should we raise an issue in docker/cli that dns_option is not also available in the v3 format?

Yes.

[ps-jay]

Thanks @shin-,
I've opened an issue in docker/cli.

[phyrwork]

Looks like this has been implemented since 1.27.0

[ilayarajamurugesan-alation]

Looks like this has been implemented since 1.27.0

@phyrwork Don't think this is related to the docker-compose version. The compose file version 3 still doesn't support dns_opt: https://docs.docker.com/compose/compose-file/compose-file-v3/

[phyrwork]

Well docker-compose 1.27+ with schema 3.9+ can certainly inject dns_opt 🤯