← docsSecurity

/implementing-network-policies-for-kubernetes

Implement Kubernetes NetworkPolicies that enforce zero-trust segmentation with determinist.

Implement Kubernetes NetworkPolicies that enforce zero-trust segmentation with deterministic validation and rollback-safe rollout controls.

Category

Security

Execution

8 steps, sequential + gated

Goal

Implement Kubernetes NetworkPolicies that enforce zero-trust segmentation with deterministic validation and rollback-safe rollout controls.

Scope

Applies to

  • +Implement Kubernetes NetworkPolicies
  • +Apply default deny and allow-list traffic
  • +Segment workloads with least-privilege network access

Does not cover

  • −Trivial changes outside the workflow domain

Triggers

"Implement Kubernetes NetworkPolicies""Apply default deny and allow-list traffic""Segment workloads with least-privilege network access""Block metadata endpoint and lateral movement"

Inputs

  • →Context: environment/system affected
  • →Scope: change boundary
  • →Constraints: policy or hard rules

Invariants

  • 01Default-deny stance is the baseline for protected namespaces unless explicitly exempted.
  • 02Allow rules must be minimal and tied to explicit service flows.
  • 03DNS and control-plane dependencies must be explicitly preserved.
  • 04Cloud metadata endpoints must remain blocked for untrusted workloads.
  • 05Validation commands must prove both blocked and allowed paths before closure.

Procedure

  1. Step 1Step 1 — **Baseline and discovery**
  2. Step 2Step 2 — **Apply default-deny foundation**
  3. Step 3Step 3 — **Allow mandatory platform traffic**
  4. Step 4Step 4 — **Implement application-specific allow rules**
  5. Step 5Step 5 — **Add cross-namespace and egress controls**
  6. Step 6Step 6 — **Block metadata endpoint access**
  7. Step 7Step 7 — **Validate behavior**
  8. Step 8Step 8 — **Rollout and rollback readiness**

Outputs

  • ▸Versioned NetworkPolicy manifests per namespace/application.
  • ▸Validation report with blocked/allowed traffic evidence.
  • ▸Change summary including known exceptions and risk notes.
  • ▸Rollback execution note (if used) or rollback readiness confirmation.

Review Gate

  • [ ]Default-deny policy exists for each protected namespace.
  • [ ]All allow rules map to explicit documented service flows.
  • [ ]DNS and required platform dependencies remain functional.
  • [ ]Metadata endpoint access is blocked where required.
  • [ ]Validation evidence proves both deny and allow outcomes.