Can't Bind Mount Host Folder Using docker-outside-of-docker

[leobaldoneto]

Hi, I created a container from inside a dev container using the docker-outside-of-docker feature. I mapped an bind mount to the host repo folder. However, the files don't appear in the bound folder inside the container.

Minimum configuration to reproduce:

.devcontainer/devcontainer.json

{
	"image": "mcr.microsoft.com/devcontainers/base:bullseye",
	"features": {
		"ghcr.io/devcontainers/features/docker-outside-of-docker:1": {}
	},
	"remoteEnv": {
		"LOCAL_WORKSPACE_FOLDER": "${localWorkspaceFolder}"
	}
}

STEPS:

• Build and connect to the dev container.
• Run the command: docker run -it --rm -v ${LOCAL_WORKSPACE_FOLDER}:/workspace debian bash

BEHAVIOR:

• Can't see any files inside container folder /workspace

EXPECTED BEHAVIOR:

• See files from local workspace folder inside container at /workspace

ADDITIONAL INFO:

• Host: Windows 11 with Docker powered by WSL 2 with Ubuntu 22.
• Docker version: 25.0.3

[superheikie]

I am having this problem as well.

[myrddraall]

This just started happening to us as well. It seems the dev container has lost a mapping somewhere and host paths are no longer valid. If I hard code the volume path that was in the env var then it won't work in the dev container but will work on the wsl host.
The only difference I'm seeing is that we get an error that the bind path cannot be found rather than an empty folder

${LOCAL_WORKSPACE_FOLDER}/app - fails in dev container, fails in wsl because the env var doesn't exist
/home/user/dev/app - fails in dev container - works in wsl
\\\\wsl.localhost\\Ubuntu-20.04\\home/user/dev/app -works in both

As a workaround i changed the devcontainer.json

{
    ...
    "containerEnv": {
        "LOCAL_WORKSPACE_FOLDER": "\\\\wsl.localhost\\${localEnv:WSL_DISTRO_NAME}\\${localWorkspaceFolder}"
    }
}

[leobaldoneto]

This just started happening to us as well. It seems the dev container has lost a mapping somewhere and host paths are no longer valid. If I hard code the volume path that was in the env var then it won't work in the dev container but will work on the wsl host.
The only difference I'm seeing is that we get an error that the bind path cannot be found rather than an empty folder

${LOCAL_WORKSPACE_FOLDER}/app - fails in dev container, fails in wsl because the env var doesn't exist
/home/user/dev/app - fails in dev container - works in wsl
\\\\wsl.localhost\\Ubuntu-20.04\\home/user/dev/app -works in both

As a workaround i changed the devcontainer.json

{
    ...
    "containerEnv": {
        "LOCAL_WORKSPACE_FOLDER": "\\\\wsl.localhost\\${localEnv:WSL_DISTRO_NAME}\\${localWorkspaceFolder}"
    }
}

It worked for me has an workaround. thanks!

[samruddhikhandale]

Thanks for the details. @gauravsaini04 Can you help investigate this issue? Thanks!

[samruddhikhandale]

@chrmarti Any thoughts on this issue?

From microsoft/vscode-remote-release#3588 (comment) it seemed like it wasn't possible before. However, moby/moby#32582 seems to have merged-in recently.

Do we need any changes on our end?

[chrmarti]

This works for me with Docker Desktop 4.30 (Docker Engine 26.1.1). Variations I have tried (all worked):

• Local workspace folder on Windows filesystem.
• Local workspace folder on WSL filesystem.
• Local workspace folder on Windows filesystem and Dev Containers: Execute in WSL enabled in settings.