dockerfile - docker VOLUME了一个目录，我在容器里添加文件，主机目录怎么没有出现？

Question

我是用dockerfile build的镜像：
VOLUME /home/user/web
我开启容器，进到bash，进到这个目录，然后新建了一个文件，
然后我回主机目录去查看，但是没有啊？不是说这样挂着的，在容器里面修改了，主机目录会马上出现吗？

Answer 1

Using VOLUME in the Dockerfile only declares a volume, which is a mount point. When mounting locally, you need to specify the local directory through -v when running to mount it on the volume you have declared. Of course, for Docker will automatically create undeclared volumes.

Answer 2

Directory to be mounted when running:

docker run -v hostpath:/home/user/web xximg

Answer 3

You need to use -v to hang in the directory. You can also consider docker-compose.