Docker / Docker
Docker daemon connection failure at unix socket path in GitLab CI/CD pipelines on Mac
Fix Docker daemon connection errors in GitLab Runner docker-autoscaler setups on cloud providers like Azure Includes evidence for Docker troubleshooting demand.
- Category
- Docker
- Error signature
Cannot connect to the Docker daemon at http://internal.tunnel.invalid- Quick fix
- Compare the failing environment with a known working setup, then change one configuration value at a time.
- Updated
What this error means
Cannot connect to the Docker daemon at http://internal.tunnel.invalid is a Docker failure pattern reported for developers trying to fix docker daemon connection errors in gitlab runner docker-autoscaler setups on cloud providers like azure. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.
Why this happens
GitLab runner issue (#37700) where docker-autoscaler in Azure fails to connect to Docker daemon. Instance reports ‘ERROR: Failed to remove network for build’ and ‘Preparation failed: Cannot connect to the Docker daemon’. Affects CI/CD pipelines for teams running auto-scaling Docker runners.
Common causes
- GitLab runner issue (#37700) where docker-autoscaler in Azure fails to connect to Docker daemon. Instance reports ‘ERROR: Failed to remove network for build’ and ‘Preparation failed: Cannot connect to the Docker daemon’. Affects CI/CD pipelines for teams running auto-scaling Docker runners.
Quick fixes
- Confirm the exact error signature matches
Cannot connect to the Docker daemon at http://internal.tunnel.invalid. - Check the Docker account, local tool state, and provider configuration involved in the failing workflow.
- Compare the failing environment with a known working setup, then change one configuration value at a time.
Platform/tool-specific checks
- Verify the command, editor, extension, or API client that produced the error.
- Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
- Avoid deleting credentials, local model data, or project settings until the failing scope is clear.
Step-by-step troubleshooting
- Capture the exact error message and the command, editor action, or request that triggered it.
- Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
- Review the source evidence below and compare it with your environment.
- Apply one change at a time and rerun the smallest failing action.
- Keep the working fix documented for the team or deployment environment.
How to prevent it
- Keep provider/tool configuration documented.
- Record non-secret diagnostics such as tool version, provider name, model name, and command path.
- Add a lightweight check before CI or production workflows depend on the tool.
Sources checked
Evidence note: GitLab runner issue (#37700) where docker-autoscaler in Azure fails to connect to Docker daemon. Instance reports ‘ERROR: Failed to remove network for build’ and ‘Preparation failed: Cannot connect to the Docker daemon’. Affects CI/CD pipelines for teams running auto-scaling Docker runners.
Related errors
- Docker
FAQ
What should I check first?
Start with the exact Cannot connect to the Docker daemon at http://internal.tunnel.invalid text and the smallest action that reproduces it.
Can I ignore this error?
No. Treat it as a failed Docker workflow until the root cause is understood.
Is this guaranteed to have one fix?
No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.
How do I know the fix worked?
Rerun the same command, editor action, or request. The fix is working when that action completes without Cannot connect to the Docker daemon at http://internal.tunnel.invalid.