docker com部署使用现有数据库，一直启动失败。 

services: 
memcached: 
image: memcached:1.6.29 
container_name: seafile-memcached 
entrypoint: memcached -m 256 
networks: 
- seafile-net 
seafile: 
image: seafileltd/seafile-mc:12.0-latest 
container_name: seafile 
ports: 
- “8080:80” 
volumes: 
- ./s2/opt/seafile-data:/shared 
environment: 
- DB_HOST=127.17.0.1 
- DB_ROOT_PASSWD=55555555 
- DB_PORT=3306 
- DB_USER=e...