Developed and delivered PID Namespace Isolation (PidMode) support for Docker within the gitlabhq/gitlab-runner repository, enabling containerized CI runners to operate with isolated process ID namespaces. This work involved updating CI/CD configurations and creating helper scripts to facilitate and validate the new isolation functionality, directly addressing security and compliance requirements for multi-tenant deployments. The implementation leveraged Go and YAML for code and configuration changes, with a focus on Docker’s namespace features and automation practices. By isolating container processes, the solution improved both the security posture and deployment flexibility of CI runners, enhancing reliability for continuous integration workflows.