Securing Kubernetes Network Policies and Sub-Processors for Compliance and Performance

Kubernetes Network Policies control traffic between Pods, Namespaces, and external services. They are enforced by the cluster network plugin, not Kubernetes itself. When applied, they define ingress and egress rules at the IP and port level inside the cluster. Without a policy, all Pods can send and receive traffic by default. With a policy in place, any traffic not explicitly allowed is denied.

A sub-processor in this context is any external service or infrastructure provider that processes network traffic on your behalf. In Kubernetes, sub-processors could be CNI plugins, managed service platforms, or vendors providing networking layers, firewall rules, or service mesh capabilities. Understanding your network stack’s sub-processors is critical for compliance, especially with GDPR or SOC 2, where data processors must be disclosed and controlled.

To secure your workloads, start with a clear mapping of communication paths. List every sub-processor involved in traffic flow—cloud networking services, third-party ingress controllers, API gateways, or external monitoring agents. Then use Network Policies to restrict communications to only those endpoints and namespaces. For example, allow only your application Pods to reach a database namespace on its service port, while denying all other traffic.

Best practices for working with Kubernetes Network Policies and sub-processors:

• Use a default deny-all policy in each Namespace.
• Apply the principle of least privilege to network traffic.
• Keep an updated inventory of all sub-processors in the cluster.
• Version-control your Network Policies as infrastructure-as-code.
• Continuously audit traffic logs to validate policies are effective.

Ignoring network boundaries in Kubernetes leaves sensitive data exposed. By combining strict Network Policies with awareness of your sub-processors, you create a transparent, enforceable security model that meets compliance and performance needs.

Want to see this approach in action? Launch a secure, real-time environment with enforced Network Policies on hoop.dev and watch it run live in minutes.