容器里如何调用/执行主机（群晖 NAS）的命令？

背景：需要自动检测油管视频更新并下载到 NAS，但群晖 DSM 上装不了文件监测的服务，但可以安装 youtube-dl 服务；想的办法是，安装可以监测文件变动的 docker，再调用 youtube-dl

实践：新建了一个容器 coppit/inotify-command 用于监测文件夹改动并执行命令，并在这个容器做了文件夹映射 https://hub.docker.com/r/coppit/inotify-command/

问题：按照 wiki，可以监测到文件夹改动，但跑到最后一步，执行主机的 youtube-dl 下载命令时显示 coppit/inotify-command，应该是容器没办法调用宿主的命令

容器运行日志： 2019-02-06 16:13:46 stdout /config/download.sh: line 6: youtube-dl: not found 2019-02-06 16:13:46 stdout [2019-02-06 16:13:46] Running command as user "root"... 2019-02-06 16:13:46 stdout [2019-02-06 16:13:46] Found existing user "root" with the proper user ID and group ID. Skipping creation of user and group... 2019-02-06 16:13:46 stdout [2019-02-06 16:13:46] watch: vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv 2019-02-06 16:13:46 stdout [2019-02-06 16:13:46] watch: Running command with user ID 0, group ID 0, and umask 0000 2019-02-06 16:13:46 stdout [2019-02-06 16:13:46] watch: Watch directory stabilized for 5 seconds. Triggering command. 2019-02-06 16:13:41 stdout [2019-02-06 16:13:41] watch: Waiting for watch directory to stabilize for 5 seconds before triggering command 2019-02-06 16:13:41 stdout [2019-02-06 16:13:41] watch: Detected change to directory /config/未命名文件夹