I have this stage on my gitlab-ci.yml but while executing i always got

ERROR 2005 (HY000): Unknown server host 'mariadb' (-3)

If i run a service mysql status, the connection is been active

# ...
database_building:
  stage: database_building
  services:
     - name: mariadb:11.0.3
       alias: mariadb
  variables:
    MYSQL_ROOT_PASSWORD: testpsw
    MYSQL_DATABASE: testdb
    MYSQL_USER: testdb
    MYSQL_PASSWORD: testdb
  before_script:
    - mysql -u testdb -ptestdb -h mariadb testdb
  script:
    - ls
# ...