I recently updated Docker for Mac, now version 3.5.2 (66501), and since then the
extends functionality in
docker-compose seems to have stopped working (no idea if that’s related though).
I have one big old
docker-compose.yaml file which is using
extends quite a bit so I was hoping not having to change that at the moment.
To try I created this dummy
version: '2.1' services: base: image: ubuntu:18.04 command: bash -c "echo 'i am base'" extender: extends: service: base hostname: extender command: bash -c "echo 'i am extender'"
When I do
docker compose up they both echo
i am base:
base_1 | i am base extender_1 | i am base
Also if I do
docker compose run extender it echos
i am base.
Source: Docker Questions