Docker 数据管理-bind mount

Use bind mounts

Bind mounts have been around since the early days of Docker. Bind mounts have limited functionality compared to volumes. When you use a bind mount, a file or directory on the host machine is mounted into a container. The file or directory is referenced by its full or relative path on the host machine. By contrast, when you use a volume, a new directory is created within Docker’s storage directory on the host machine, and Docker manages that directory’s contents.

Start a container with a bind mount

Consider a case where you have a directory source and that when you build the source code, the artifacts are saved into another directory source/target/. You want the artifacts to be available to the container at /app/, and you want the container to get access to a new build each time you build the source on your development host. Use the following command to bind-mount the target/ directory into your container at /app/. Run the command from within the source directory. The $(pwd) sub-command expands to the current working directory on Linux or macOS hosts.

The --mount and -v examples below produce the same result. You can’t run them both unless you remove the devtest container after running the first one.

--mount 语法格式：

$ docker run -d 
  -it 
  --name devtest 
  --mount type=bind,source="$(pwd)"/target,target=/app 
  nginx:latest

-v 语法格式：

$ docker run -d 
  -it 
  --name devtest 
  -v "$(pwd)"/target:/app 
  nginx:latest

Mounting into a non-empty directory on the container

If you bind-mount into a non-empty directory on the container, the directory’s existing contents are obscured(覆盖) by the bind mount. This can be beneficial, such as when you want to test a new version of your application without building a new image. However, it can also be surprising and this behavior differs from that of docker volumes.