具有Redis的Symfony应用在Gitlab CI中失败

Question

我在Symfony应用程序中使用REDIS，今天Gitlab CI停止工作并出现错误（在作曲家安装并清除缓存后）：

!!  In AbstractConnection.php line 155:
!!                                                                                 
!!    php_network_getaddresses: getaddrinfo failed: Name does not resolve [tcp://  
!!    redis:6379]    

这是我的gitlab-ci.yml：

image: docker:latest

services:
    - docker:dind
    - name: redis:5-alpine
      alias: redis

stages:
    - dependencies
    - build-docker

variables:
    #REDIS_PORT: 6379 - doesn't help
    #REDIS_HOST: redis - doesn't help

dependencies:
    stage: dependencies
    image: docker
    cache:
        paths:
            - bin
            - vendor
            - config/packages
            - public/bundles
        policy: push
    script:
        - sh ./run composer install --ignore-platform-reqs --prefer-dist --optimize-autoloader
    except:
        - tags

Gitlab CI可以运行到今天早上……有人可以帮忙吗？非常感谢。