docker-compose version important?

[Jesse Hitch]

The default versions of docker.io and docker-compose that you install when you use the standard repos provided via apt-get in Ubuntu 16.04.3 complain when I run docker-compose --build:

$ sudo docker-compose up --build
ERROR: Version in "./docker-compose.yml" is unsupported. You might be seeing this error because you're using the wrong Compose file version. Either specify a version of "2" (or "2.0") and place your service definitions under the `services` key, or omit the `version` key and place your service definitions at the root of the file to use version 1.
For more on the Compose file format versions, see https://docs.docker.com/compose/compose-file/

I switched the version to 2 in the docker-compose.yml file, and it works, but was there something in 3 we needed to make all of this work, or is version 2 of the docker-compose engine sufficient?

[AAK]

As far as Reminiscence is concerned, there is no difference between version 2 and 3 of docker-compose.yml file. Both can be used.

I haven't tested docker method on ubuntu-16.04, that's why I didn't know about docker-compose version available in it. Thanks for testing it out.

I'll add ubuntu-16.04 specific note in installation procedure.