This is my sample docker-compose.yml file. version: '2'
config-server:
  image: ccc/config-server
  restart: always
registration-server:
  image: ccc/registration-server
  restart: always
  ports:
    - 1111:1111
 When I use docker-compose up -d I get an error:  "ERROR: The Compose file './docker-compose.yml' is invalid because:
Additional properties are not allowed ('registration-server', 'config-server' were unexpected)

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/