docker-compose.yaml

version: '2'
networks:
  mongocluster_default:
    external: true
services:
  rs_shard_server2:
    image: mongo:3.4
    command: mongod -f /etc/mongod/mongod.conf --directoryperdb --shardsvr --replSet "rs-shard2-server"
    networks:
     - "mongocluster_default"
    volumes:
      - /database/vol/key.file:/data/mongodb/key.file
      - /database/vol/shard2/config:/etc/mongod
      - /database/vol/shard2/db:/data/db
    ports:
      - "10041:27018"
    restart:
      always
    container_name:
      rs_shard_server2
    ulimits:
      nofile:
        soft: 300000
        hard: 300000

若出现以下报错

Service "rs_shard_server2" uses an undefined network "mongocluster_default"

请确在services同级声明一下外部网络

networks:
  mongocluster_default:
    external: true