Way of Creating D drive inside windows container agent in azure devops

Question

Please suggest a way to create D drive in the windows container agent.

I am following answer from below but not clear

https://forums.docker.com/t/way-to-create-d-drive-in-windows-container/148273

Answer 1

Hi Diptesh Kumar

Creating a D drive inside a Windows container agent in Azure DevOps isn't straightforward because containers usually operate with a single root filesystem (C:). However, you can achieve similar functionality using volume mounts or virtual drives.

Here are some methods:

1. You can mount an additional volume to simulate a D: drive:

      docker run -v D:\data:C:\mnt --name my-agent windows-container-image
   

   This maps D:\data from the host to C:\mnt inside the container.
2. Or you can create a virtual drive inside the container using subst: This makes C:\mnt appear as D: inside the container.

      subst D: C:\mnt
   

Hope this helps!

Please Let me know if you have any queries.

Answer 2

HI Durga,

1.

Document you have given is not opening, please share me the working link

2.

Below highlighted indicates container path right ?

Answer 3

Hi Diptesh Kumar

As per discussion in private message,

Let me Clarify each one of your questions:

Will software on D: be embedded into the image?

1. No, the D: drive itself will not be embedded into the container image. If you're mounting D: as a volume (-v D:\agentdata:C:\persistent), the software installed on D: will reside on the host, not inside the container image.

Will D: remain intact and usable when the image is deployed in Kubernetes (AKS)?

1. Not automatically. Kubernetes doesn’t know about subst or drive letters
2. When deploying to AKS, the container image itself will be immutable. Since D: is being mapped dynamically, it won't exist inside the Kubernetes pod unless explicitly configured. You will need to use persistent storage like PVC's - Persistent Volume Claims.

Can this setup remain consistent across AKS deployments?

1. Yes, but only if you use a Persistent Volume (PV).

If the goal is to keep software installed on D: store it in an Azure Files share.

For this Go to Azure Portal -> Create an Azure Storage Account -> Then Navigate to File Shares and Create it. Now, you’ll map D: inside your Windows container using the SMB protocol.

Inside Storage Account, go to Access Keys and copy the key and then go to your File Share and Connect via SMB. Copy the provided net use command.

Now Inside the Windows container, run:

net use D: \\mywindowsagentstorage.file.core.windows.net\persistent-agent-share /user:mywindowsagentstorage xxxxxxxxxxxx==

This mounts D: inside the container and persists software installed there.

In AKS, ensure the drive remains consistent. Define PersistentVolume

apiVersion: v1
kind: PersistentVolume
metadata:
  name: azure-file-pv
spec:
  capacity:
    storage: 100Gi
  accessModes:
    - ReadWriteMany
  azureFile:
    secretName: azure-secret
    shareName: persistent-agent-share
    storageAccountName: mywindowsagentstorage #your storage account name

In your Kubernetes manifest, Create PVC:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: azure-file-pvc
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 100Gi
  volumeName: azure-file-pv

Mount it inside the pod:

containers:
  - name: windows-agent-container
    image: my-agent-image
    volumeMounts:
      - name: azure-storage
        mountPath: /persistent
volumes:
  - name: azure-storage
    persistentVolumeClaim:
      claimName: azure-file-pvc

Inside the container, run: subst D: C:\persistent

This ensures D: drive remains accessible.

Another approach you can try to use an init container in Kubernetes to restore the D: drive mapping before the main workload runs.

Hope this helps!

Please Let me know if you have any queries.

If you found the information helpful, please click "Upvote" on the post to let us know and consider accepting the answer as the token of appreciation. Thank You.

Answer 4

Hi Durga,

you mean both the steps, should be done one is creating file in storage account and using same file share in AKS? to have persistent storage for PODS(Agents ), am i right?

Answer 5

Hi Diptesh Kumar

Yes, to ensure persistent storage for your Windows container agents running in AKS, you need to follow both steps.

Feel free to reach out if you have any further queries.

If you found the information helpful, please click "Upvote" on the post to let us know and consider accepting the answer as the token of appreciation. Thank You.