Mount a Windows fileshare within a self-hosted runner using CIFS

[Ryan Taylor]

We've configured a linux docker self hosted runner in our environment and need to move build artifacts from the docker container to a windows file share. We do not have ssh or sftp available and cannot use those utilities at this time.

I attempted to mount the windows file share using CIFS as we do something similar on our windows containers (in Jenkins) using net use.

mount -t cifs \
  -o username=your_user,password=your_password,domain=your_domain \
  //your/file/share \
  /mnt/share

However, this does not seem possible as I am getting the following error:

Unable to apply new capability set.

How can I mount my windows file share within a self-runner linux docker container?

Update 2025/10/11: 

It appears this this may now be possible with Runtime v3 with the Privileged flag but I'm still not sure on a couple things.

1. Does this mean I am running a docker container instead a docker container?
2. Is there no way to run the "top" container in privileged mode in my own self hosted runner?

#2 with something like `privileged: true` would be beneficial as I could run multiple steps in the privileged container via the scripts property(ies) rather than encoding them in the docker run command itself (which may be rather long when I have multiple steps).

[Ryan Taylor]

It appears this this may now be possible with Runtime v3 with the Privileged flag using Docker in Docker. Here's a pipeline working pipeline. (Add the definitions block was key as discussed in this post)

definitions:
  services:
    docker-custom:
      type: docker
      image: docker:dind

image: atlassian/default-image:4

pipelines:
  default:
    - step:
        name: Privileged Runner
        runtime:
          cloud:
            version: 3
        services:
          - docker-custom
        runs-on:
          - "self.hosted"
          - "linux"
        script:
          - docker run --privileged alpine:3 sh -c "apk update && apk add cifs-utils && mkdir /mnt/gis && mount -t cifs -o username=$USR,password=$ PSW,domain=$DOMAIN //server.domain.local/share/gis /mnt/gis && ls /mnt/gis"

It's a bit messy though as, AFAIK, the entire command needs to be executed in the docker run -c and would not be available in subsequent commands 

What I was really hoping for was something more akin to the following (note the privileged prop).

# EXAMPLE ONLY. NOT A WORKING SAMPLE
pipelines:
  default:
    - step:
        name: Privileged Runner
        runtime:
          cloud:
            version: 3
            privileged: true # mark the container as privileged
        runs-on:
          - "self.hosted"
          - "linux"
        script:
          - apk update
          - apk add cifs-utils
          - mkdir /mnt/gis 
          - mount -t cifs -o username=$USR,password=$ PSW,domain=$DOMAIN //server.domain.local/share/gis /mnt/gis
          - ls /mnt/gis

Ultimately, though I have settled installing OpenSSH on the Windows Server and using scp to copy files over. This means I don't need to use DinD and the pipeline becomes simpler. Will likely use rsync for better performance, and syncing features.