Self hosted Bitbucket pipeline fails to run docker commands

[Jan Martin]

We have a self-hosted Windows pipeline.

We are trying to run docker commands, e.g. docker build .

When we attempt to run this same command from terminal it works, but the pipeline runner instead gets this error:

+ docker build .

DEPRECATED: The legacy builder is deprecated and will be removed in a future release.

Install the buildx component to build images with BuildKit:

https://docs.docker.com/go/buildx/

error during connect: Post "http://localhost:2375/v1.54/build?dockerfile=myproject%2FDockerfile&t=myproject.azurecr.io%2Fmyproject&version=1": dial tcp [::1]:2375: connectex: No connection could be made because the target machine actively refused it.

[Arkadiusz Wroblewski]

Hello @Jan Martin 

First - Exposing 2375 - is Bananas. @Viswanathan Ramachandran 

This error happens because Bitbucket Pipelines automatically injects a `DOCKER_HOST` variable, forcing Docker to look for a TCP connection on port 2375 instead of using the standard Windows named pipe.

Clear the variable at the start of your PowerShell script step using `$Env:DOCKER_HOST = ""` or set it explicitly to `"npipe:////./pipe/docker_engine"`. Avoid enabling TCP port 2375 in Docker Desktop as that creates an unnecessary security risk. If clearing the variable results in a permission error, run `whoami` in the step to verify that the Windows service account running your runner actually has access to Docker.

Here some reference from ancient Topic

https://community.atlassian.com/forums/Bitbucket-questions/Unable-to-build-push-Windows-container-via-Windows-Runner/qaq-p/2189404 

Best,

Arek 🤠

[Viswanathan Ramachandran]

Hi @Arkadiusz Wroblewski 

My bad. I agree completely. I should have been more clearer. I'll just try to rule out the error and then remove again. Thank you for the mention and pointing out the reference article 

[Arkadiusz Wroblewski]

All fine. I just wanna point that Exposing ports is never good idea 

[Viswanathan Ramachandran]

hi @Jan Martin 

The issue looks like a protocol/port mismatch between the Bitbucket Runner and Docker.  Can you try one of these approaches:

Option A: Switch to Windows Named Pipes

You can explicitly force the runner to use the Windows Named Pipe by setting the DOCKER_HOST environment variable in your bitbucket-pipelines.yml

Option B : Enable TCP 2375 on Docker Daemon (not recommended)

alternatively, just checking, I hope your permissions are alright and set correctly? 

May be you run the Bitbucket Runner service as the same user running Docker Desktop, or try switching to Docker Engine Service.