GitOps with GitLab: The CI/CD Tunnel

Introduces the 'CI/CD tunnel' feature of the GitLab Kubernetes Agent, which allows GitLab CI/CD jobs to directly access Kubernetes clusters. Details how to configure the agent for CI access, share connections across projects and groups, and use the Cluster Management Project template to deploy applications like NGINX Ingress and GitLab Runners. Demonstrates setting KUBECONFIG environment variables and using `kubectl` within CI jobs.