PostgreSQL: could not translate host name

GitLab CI/CD
1

Hi,

I have the following for my Rails app:

image: "ruby:2.6"

services:
  - redis:latest

variables:
  BUNDLE_CACHE: "vendor/bundle/"
  LC_ALL: C.UTF-8
  LANG: en_US.UTF-8
  LANGUAGE: en_US.UTF-8
  RAILS_ENV: test
  POSTGRES_USER: postgres
  POSTGRES_PASSWORD: ""
  POSTGRES_HOST: "postgresql"
  POSTGRES_DB: ci
  DOCKER_HOST: tcp://docker:2375
  DOCKER_DRIVER: overlay2

.default_cache: &default_cache
  cache:
    untracked: true
    key: "gems-$CI_BUILD_REF_NAME"
    paths:
      - node_modules/
      - vendor/bundle/
      - public/

build:
  <<: *default_cache
  stage: build
  services:
    - name: mdillon/postgis:9.6
      alias: postgresql
  script:
    - apt-get update -qq && apt-get install -y -qq nodejs postgresql-client
    - ruby -v
    - cp config/database.yml.example config/database.yml
    - gem install bundler --no-document
    - bundle config set deployment 'true'
    - bundle config set path 'vendor/bundle/'
    - bundle install --jobs $(nproc) "${FLAGS[@]}"
    - psql -h postgresql -c "create user some_user with password '';

I’m just trying to connect to PostgreSQL, however I get the error:

psql: could not translate host name "postgresql" to address: Name or service not known
ERROR: Job failed: command terminated with exit code 1

This is with “Running with gitlab-runner 12.5.0 (577f813d) on gitlab-runner-artifact-uploader-847885b7bb-8jg6l 6EAiZtt1”.

When I run it locally with “gitlab-runner exec docker build”, it works perfectly fine.

Any hints?

Thank you

Darius