How to enable redis on kubernetes cluster?

I’ve gotten the redis service up and running on the shared runners by adding it to my task in .gitlab-ci.yml

py27:
  stage: run
  image: python:2.7
  script:
    - mkdir -p build/coverage
    - pip install -r requirements.txt
    - pytest --color=no --verbose --ignore=almanac/migrations --cov=almanac --cov-config=.coveragerc tests
    - cp .coverage build/coverage/py27.coverage
  services:
    - redis:latest
  artifacts:
    paths:
      - build/*

However, when the task is ran by the kubernetes cluster (GKE) it cannot find the redis service/name:

almanac/weather/dkmetar.py:188: in Metar
    rval = r.get(redis_key)
/usr/local/lib/python2.7/site-packages/redis/client.py:1264: in get
    return self.execute_command('GET', name)
/usr/local/lib/python2.7/site-packages/redis/client.py:772: in execute_command
    connection = pool.get_connection(command_name, **options)
/usr/local/lib/python2.7/site-packages/redis/connection.py:994: in get_connection
    connection.connect()
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = Connection<host=redis,port=6379,db=0>

    def connect(self):
        "Connects to the Redis server if not already connected"
        if self._sock:
            return
        try:
            sock = self._connect()
        except socket.timeout:
            raise TimeoutError("Timeout connecting to server")
        except socket.error:
            e = sys.exc_info()[1]
>           raise ConnectionError(self._error_message(e))
E           ConnectionError: Error -2 connecting to redis:6379. Name or service not known.

/usr/local/lib/python2.7/site-packages/redis/connection.py:497: ConnectionError

I only have about 3 weeks experience with gitlab, docker, and kubernetes; so I’m guessing I’ve missed something obvious…?