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devopscritical PriorityID: cilium-ebpf-socket-mtls-guardrail

Cilium eBPF Host-Level Kernel Socket mTLS & Zero-Trust Invariant

Enforces sidecarless, kernel-space mutual authentication and transparent cryptographic encapsulation using Cilium eBPF sockops, WireGuard/IPsec acceleration, and SPIRE/SPIFFE attestation. Prohibits the injection of legacy user-space sidecar proxies that induce memory fragmentation and double-serialization penalties. Guarantees that socket-level redirection (sockmap/bpf_msg) remains unbroken across all pod-to-pod communication channels.

Prohibited Anti-Pattern: Deploying Heavyweight User-Space Sidecar Proxies That Break eBPF Sockops Acceleration and Induce Memory Bloat

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---
description: Cilium eBPF Host-Level Kernel Socket mTLS & Zero-Trust Invariant - Enforces sidecarless, kernel-space mutual authentication and transparent cryptographic encapsulation using Cilium eBPF sockops, WireGuard/IPsec acceleration, and SPIRE/SPIFFE attestation. Prohibits the injection of legacy user-space sidecar proxies that induce memory fragmentation and double-serialization penalties. Guarantees that socket-level redirection (sockmap/bpf_msg) remains unbroken across all pod-to-pod communication channels.
globs: **/cilium*.{yaml,yml}, **/values*.{yaml,yml}, **/charts/**/*.{yaml,yml}, **/manifests/**/*.{yaml,yml}, **/k8s/**/*.{yaml,yml}
alwaysApply: true
verified_by: "agentrules.org"
license: "CC-BY-4.0"
source: "https://agentrules.org/rules/cilium-ebpf-socket-mtls-guardrail"
---

# Cilium eBPF Host-Level Kernel Socket mTLS & Zero-Trust Invariant

> **Severity**: CRITICAL | **Category**: devops
> **Anti-Pattern Warning**: Deploying Heavyweight User-Space Sidecar Proxies That Break eBPF Sockops Acceleration and Induce Memory Bloat

## System Constraints
You are a Principal Infrastructure & Systems Architect enforcing Cilium eBPF host-level socket-layer mTLS invariants. Reject any architecture that forces pod-to-pod traffic through user-space Envoy sidecars. Ensure that all Cilium installations configure kernel-space socket operations (sockops), transparent cryptographic encapsulation (WireGuard or IPsec), and non-intrusive SPIRE/SPIFFE mutual authentication at the Linux socket boundary.

## Strict Guidelines
- Engineers MUST ALWAYS enable sockops (`sockops.enabled: true`) in Cilium Helm values to allow kernel-layer BPF socket redirection (`sockmap`).
- Engineers MUST NOT inject third-party user-space sidecar proxies (e.g., Istio Envoy sidecars, Linkerd proxy containers) for mTLS when Cilium eBPF is provisioned as the cluster CNI.
- Services MUST declare mutual authentication using `CiliumNetworkPolicy` specs containing `authentication.mode: required` targeting SPIRE-attested workloads.
- Engineers MUST enable transparent kernel-level cryptographic encapsulation (`encryption.enabled: true` with `encryption.type: wireguard` or `encryption.type: ipsec`) across all cluster nodes.
- Helm values SHOULD enforce host-reachable services and eBPF host routing (`bpf.masquerade: true` and `bpf.hostRouting: true`) to bypass the host network stack for local pod-to-pod transfers.

## Bad vs Good Implementations
### Cilium Helm Configuration & Strict Kernel mTLS Policy

#### Bad Antipattern (AI Common Hallucination)
> **Why it fails**: This configuration disables eBPF sockops, relies on an unauthenticated plaintext overlay, and delegates mTLS to heavyweight user-space sidecars. This creates serialization bottlenecks, doubles container memory overhead, and defeats Cilium's zero-copy kernel socket routing.
```yaml
# Anti-Pattern: User-space proxy sidecar fallback, disabled eBPF acceleration
env: production
sidecar:
  istio:
    enabled: true # Incurs double serialization & context switching penalties

cilium:
  sockops:
    enabled: false # Disables kernel socket bypass (bpf_sock_ops)
  encryption:
    enabled: false # Plaintext pod-to-pod transport across node fabrics
  authentication:
    mutual:
      spire:
        enabled: false
---
apiVersion: "cilium.io/v2"
kind: CiliumNetworkPolicy
metadata:
  name: insecure-service-policy
spec:
  endpointSelector:
    matchLabels:
      app: payment-gateway
  ingress:
    - fromEndpoints:
        - matchLabels:
            app: checkout-frontend
      # Missing authentication enforcement; traffic is not cryptographically verified at socket layer
```

#### Production Standard (Correct)
> **Standard**: This configuration enforces kernel-level WireGuard encryption, enables eBPF sockops for microsecond TCP bypass, and activates Cilium's sidecarless SPIRE integration, ensuring zero-trust pod-to-pod cryptographic integrity directly inside the Linux socket layer.
```yaml
# Production Invariant: Kernel-Level Socket Redirection with eBPF and SPIRE mTLS
cilium:
  bpf:
    masquerade: true
    hostRouting: true
  sockops:
    enabled: true # Enables BPF socket-map redirects for co-located and node endpoints
  encryption:
    enabled: true
    type: wireguard # Enforces kernel-level cryptographic encapsulation on the wire
    nodeEncryption: true
  authentication:
    mutual:
      spire:
        enabled: true
        install:
          server:
            dataStorage:
              enabled: true
---
apiVersion: "cilium.io/v2"
kind: CiliumNetworkPolicy
metadata:
  name: strict-kernel-mtls-policy
  namespace: production
spec:
  endpointSelector:
    matchLabels:
      app: payment-gateway
  ingress:
    - fromEndpoints:
        - matchLabels:
            app: checkout-frontend
      authentication:
        mode: required # Mandates SPIFFE-attested kernel-enforced mTLS handshake
      toPorts:
        - ports:
            - port: "8443"
              protocol: TCP
```
Recommended MCP Servers (mcp-serverlist.com)

Equip agent with system tools to verify code for this stack.

Kubernetes Context Engine
Validates live Kubernetes cluster state, CRDs, and CiliumNetworkPolicy mutual authentication constraints.
Recommended Agent Skills (askills.dev)

Ready-to-use executable skill functions tailored to this stack.

Cilium CLI Inspector
Verifies BPF map allocation, sockops redirection status, and mutual authentication handshakes via 'cilium bpf' and 'cilium status'.
Architectural Specification & Invariant Rationale

Architectural Invariant Design: Cilium eBPF Host-Level Kernel Socket mTLS & Zero-Trust Invariant

Cilium eBPF Host-Level Kernel Socket mTLS & Zero-Trust Invariant defines an industrial-grade behavioral standard for devops engineering. Enforces sidecarless, kernel-space mutual authentication and transparent cryptographic encapsulation using Cilium eBPF sockops, WireGuard/IPsec acceleration, and SPIRE/SPIFFE attestation. Prohibits the injection of legacy user-space sidecar proxies that induce memory fragmentation and double-serialization penalties. Guarantees that socket-level redirection (sockmap/bpf_msg) remains unbroken across all pod-to-pod communication channels. Modern software architectures require strict adherence to deterministic patterns to guarantee high availability, maintainability, and zero security vulnerabilities.

Framework Paradigm Shift & Drift MechanicsLLMs are trained on millions of open-source repositories containing outdated code, legacy idioms, and unpatched antipatterns. When coding assistants generate implementations for this stack, they default to common statistical tokens: Deploying Heavyweight User-Space Sidecar Proxies That Break eBPF Sockops Acceleration and Induce Memory Bloat Without an explicit system instruction file, developers spend hours debugging silent failures.
Failure Modes & Production Blast Radius

Hazard Analysis: What Breaks Without This Rule

The following failure modes have been cataloged from hundreds of hours of production code reviews where AI assistants produced non-compliant implementations:

Failure ModeAI Symptom (The Anti-Pattern)SeverityProduction Impact & Remedy
AI Hallucination & Deprecation DriftDeploying Heavyweight User-Space Sidecar Proxies That Break eBPF Sockops Acceleration and Induce Memory BloatCritical
Violating this industrial standard introduces regression bugs, security risks, and unexpected runtime failures in production.
Enforce explicit behavioral system directives across all AI coding assistants in your repository.
Silent Architecture InconsistencyAI assistants produce mixed paradigms across files, creating fragmented codebase conventions.Medium
Increases cognitive load during code reviews and leads to maintenance debt across engineering teams.
Pin project conventions in .cursor/rules, CLAUDE.md, and AGENTS.md so all team agents follow identical guardrails.
Architectural Directives in Detail

Step-by-Step Production Directives

Each rule constraint below is injected into the AI agent's system prompt to establish deterministic boundaries:

1

Engineers MUST ALWAYS enable sockops (`sockops.enabled

Engineers MUST ALWAYS enable sockops (`sockops.enabled: true`) in Cilium Helm values to allow kernel-layer BPF socket redirection (`sockmap`).

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
2

Engineers MUST NOT inject third-party user-space sidecar proxies (e.g., Istio Envoy sidecars, Linkerd proxy containers) for mTLS when Cilium eBPF is provisioned as the cluster CNI.

Engineers MUST NOT inject third-party user-space sidecar proxies (e.g., Istio Envoy sidecars, Linkerd proxy containers) for mTLS when Cilium eBPF is provisioned as the cluster CNI.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
3

Services MUST declare mutual authentication using `CiliumNetworkPolicy` specs containing `authentication.mode

Services MUST declare mutual authentication using `CiliumNetworkPolicy` specs containing `authentication.mode: required` targeting SPIRE-attested workloads.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
4

Engineers MUST enable transparent kernel-level cryptographic encapsulation (`encryption.enabled

Engineers MUST enable transparent kernel-level cryptographic encapsulation (`encryption.enabled: true` with `encryption.type: wireguard` or `encryption.type: ipsec`) across all cluster nodes.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
5

Helm values SHOULD enforce host-reachable services and eBPF host routing (`bpf.masquerade

Helm values SHOULD enforce host-reachable services and eBPF host routing (`bpf.masquerade: true` and `bpf.hostRouting: true`) to bypass the host network stack for local pod-to-pod transfers.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.
Enforcement:Integrated into the Agent Pack rule file. When Cursor, Claude Code, or Codex processes this prompt, it applies this constraint before emitting syntax.
Technical Questions & Answers

Frequently Asked Technical Questions

Common questions developers face when configuring AI coding assistants for this stack:

Q:Why is Cilium eBPF Host-Level Kernel Socket mTLS & Zero-Trust Invariant critical for AI coding assistants?

Enforces sidecarless, kernel-space mutual authentication and transparent cryptographic encapsulation using Cilium eBPF sockops, WireGuard/IPsec acceleration, and SPIRE/SPIFFE attestation. Prohibits the injection of legacy user-space sidecar proxies that induce memory fragmentation and double-serialization penalties. Guarantees that socket-level redirection (sockmap/bpf_msg) remains unbroken across all pod-to-pod communication channels. Without explicit behavioral boundaries, AI coding assistants (Cursor, Claude Code, Windsurf, Codex) rely on training data averages, which frequently produce deprecated, inefficient, or vulnerable code patterns.

Q:How does adopting this rule prevent AI hallucinations?

This rule explicitly declares what the AI must avoid (Deploying Heavyweight User-Space Sidecar Proxies That Break eBPF Sockops Acceleration and Induce Memory Bloat) and prescribes verified positive examples. Grounding the LLM with negative and positive pairs eliminates guesswork.

Q:Which AI coding environments are supported?

This specification is multi-platform compatible: Cursor (.cursor/rules/*.mdc & .cursorrules), Anthropic Claude Code (CLAUDE.md), Windsurf (.windsurfrules), Codex / Cline (AGENTS.md), and GitHub Copilot (.github/copilot-instructions.md).

Q:Can I combine this rule with other technology stacks?

Yes. Use the Interactive Stack Builder or download an Agent Pack to merge this rule with other frontend, backend, database, security, and DevOps rules without syntax collision.

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