Worked on the gitlabhq/gitlab-runner repository to add overlay volume mounts support in the Docker Executor for Linux environments. This involved implementing overlay mount parsing with recognition of the 'O' mode, comprehensive SELinux label handling, and support for propagation options to ensure correct and secure volume semantics. The work included expanding test coverage to validate overlay mount parsing and address edge cases, reducing the risk of regressions in CI workflows. All changes were documented to aid future enhancements. The project was developed using Go and leveraged Docker and Linux volume management expertise to improve reliability and maintainability in containerized builds.