Container volumes - ContainerPath other than C: drive?

[mwieczorek]

Is it possible to have other drives in container than C:?
If I run:

docker run -it -v d:\new-data-volume windowsservercore cmd

I get and error:

C:\Docker\docker.exe: Error response from daemon: container 
ad21aac97cd17479a596c302dfe8cb433f425789cc51ff3b5043815730a6ad39 encountered an error during CreateContainer failed in Win32: 
The parameter is incorrect. (0x57) extra info: 
{"SystemType":"Container","Name":"ad21aac97cd17479a596c302dfe8cb433f425789cc51ff3b5043815730a6ad39","Owner":"docker","IsDummy":false,"VolumePath":"\\\\?\\Volume{57c5c9fc-457a-11e6-b901-9f8c073a0421}",
"IgnoreFlushesDuringBoot":true,"LayerFolderPath":"C:\\ProgramData\\docker\\windowsfilter\\ad21aac97cd17479a596c302dfe8cb433f425789cc51ff3b5043815730a6ad39","Layers":[{"ID":"d8d90394-03a9-5513-976b-9923314296d4",
"Path":"C:\\ProgramData\\Microsoft\\Windows\\Images\\CN=Microsoft_WindowsServerCore_10.0.14300.1000"}],"HostName":"ad21aac97cd1",
"MappedDirectories":[{"HostPath":"C:\\ProgramData\\docker\\volumes\\127336be0d3b886a0b956da32613eb340f1a932e3f822b6a7caad59b3e83e379\\_data","ContainerPath":"d:\\new-data-volume","ReadOnly":false}],
"SandboxPath":"","HvPartition":false,"EndpointList":["354a7efe-552d-4e93-859e-eedfcef48497"],"HvRuntime":null,"Servicing":false}.

Of course

docker run -it -v c:\new-data-volume windowsservercore cmd

works.

[rohitjaini]

You should be able to get it work with below command: docker run -it --volume=d:\new-data-volume:c:\datavolume windowsservercore cmd

[mwieczorek]

@rohitjaini Well, that's not what I want.
In your example D:\ is in source (host) and C:\ is in destination (container).
My question is about opposite direction

[jstarks]

We support mapping a whole second drive letter, but for now, not portions of it. So you can say

docker run -it -v d: windowsservercore cmd

and get a volume as drive D: in the container. But you can't write d:\data-volume or event d:\; it must be d:.

[mwieczorek]

@jstarks Thank you for the explanation

[neilpeterson]

Thanks @jstarks - I've added this to documentation.

[dtretyakov]

@jstarks, @neilpeterson, @scooley, could you please clarify how non C drive volume mapping should work?
For example:

D:\> mkdir folder
D:\> docker run --rm -it -v D: microsoft/nanoserver:1709 cmd /c "dir D:"
 Directory of D:\

05/11/2018  11:29 AM    <DIR>          .
05/11/2018  11:29 AM    <DIR>          ..
               0 File(s)              0 bytes
               2 Dir(s)  94,127,910,912 bytes free

When starting powershell in the container it fails with a following error:

Attempting to perform the InitializeDefaultDrives operation on the 'FileSystem' provider failed.
dir : Cannot find drive. A drive with the name 'D' does not exist.
At line:1 char:1
+ dir D:
+ ~~~~~~
+ CategoryInfo          : ObjectNotFound: (D:String) [Get-ChildItem], DriveNotFoundException
+ FullyQualifiedErrorId : DriveNotFound,Microsoft.PowerShell.Commands.GetChildItemCommand

So it looks like it just creates an empty drive D: inside container and does not provide any content from the host filesystem or this drive has problems with permissions to access it.

D:\> docker info
Containers: 4
 Running: 1
 Paused: 0
 Stopped: 3
Images: 11
Server Version: 18.04.0-ce
Storage Driver: windowsfilter (windows) lcow (linux)
 Windows:
 LCOW:
Logging Driver: json-file
Plugins:
 Volume: local
 Network: ics l2bridge l2tunnel nat null overlay transparent
 Log: awslogs etwlogs fluentd gelf json-file logentries splunk syslog
Swarm: inactive
Default Isolation: hyperv
Kernel Version: 10.0 16299 (16299.431.amd64fre.rs3_release_svc_escrow.180502-1908)
Operating System: Windows 10 Pro Version 1709 (OS Build 16299.431)
OSType: windows
Architecture: x86_64
CPUs: 8
Total Memory: 63.97GiB
Name: munit-199
ID: LLWJ:P3CA:ITHO:GODJ:OCUX:R4LO:6ASW:FPGJ:RWX3:UT6D:L7ZR:7LG4
Docker Root Dir: C:\ProgramData\Docker
Debug Mode (client): false
Debug Mode (server): true
 File Descriptors: -1
 Goroutines: 30
 System Time: 2018-05-11T11:29:51.2341926+02:00
 EventsListeners: 1
Registry: https://index.docker.io/v1/
Labels:
Experimental: true
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false

[chaos95]

Hi folks, developer from the future here, digging deep into the past for an issue I'm currently having while trying to run a WS2019 container.

It's taken me a few hours of detective work to find this issue and the corresponding doc fix that was made in response to it - unfortunately that fix seems to have been lost in translation some time in the last 4 years, because the current persistent volumes doc at https://docs.microsoft.com/en-us/virtualization/windowscontainers/manage-containers/persistent-storage doesn't mention this limitation.

My experience in practice, however, shows that it still exists. @jstarks - would you happen to know if there has been any progress made on this? I'm guessing it never quite had enough priority to be addressed, which is fine, but I'd been interested to find out if it's ever been looked at since.

At any rate, I will aim to submit a PR here that adds in a mention of the limitation sometime soon, work permitting.