Kubernetes & Cloud-Native Security Hardening

Initial problem

The platform's runtime security model relied on detection-only monitoring — visibility into suspicious activity after the fact, not the ability to block it as it happened. On an OS designed with no shell access as a core security property, that gap mattered: detection-based tooling built for traditional Linux environments couldn't take advantage of what the platform's architecture already made possible.

Scope

• Runtime workload security — detection vs. enforcement evaluation
• Policy-as-code for admission control and pod security standards
• Workload sandboxing and isolation for untrusted or high-risk containers
• Event pipeline design for security-relevant runtime signals

Engineering work

Runtime enforcement tooling was evaluated against the platform's specific constraints and selected specifically for kernel-level blocking capability — not just alerting — a better architectural fit for an OS built around minimal attack surface and no interactive shell.

Policy-as-code was implemented for admission control, using exception mechanisms scoped narrowly for legitimate edge cases rather than broad allowlisting that would undermine the policy's purpose.

Workload sandboxing options — including gVisor, Kata Containers, and Firecracker-based isolation — were evaluated directly against the platform's kernel virtualization requirements. Firecracker via Kata was selected and validated end-to-end, including confirming the underlying virtualization device requirements were met in the target environment. A specific incompatibility between one sandboxing approach and Docker-in-Docker workloads was identified during evaluation, with an isolated alternative runtime recommended in its place.

Deliverables

• Runtime enforcement tooling deployed and validated against real workload behavior
• Admission-control policy set with documented exception handling
• Sandboxing runtime selection with validated compatibility against platform constraints
• Architecture documentation covering the enforcement and isolation model end-to-end

Validation

Enforcement behavior was validated against representative workload scenarios, confirming policy violations were blocked rather than merely logged, and that the selected sandboxing runtime operated correctly under the platform's specific kernel virtualization requirements.