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devopscritical PriorityID: cilium-ebpf-sidecarless-spiffe-attestation-guardrail

eBPF Cilium Sidecarless SPIFFE Workload Identity Attestation Guardrail

Enforces non-bypassable, kernel-level cryptographic identity verification across Kubernetes microservices using Cilium eBPF and SPIRE. Eliminates sidecar proxy CPU, memory, and latency overheads by delegating mutual workload attestation and mTLS handshakes directly to the node-level eBPF socket layer.

Prohibited Anti-Pattern: Injecting Per-Pod Envoy Sidecars and Insecure Host-IP Network Policies Lacking Cryptographic Identity

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---
description: eBPF Cilium Sidecarless SPIFFE Workload Identity Attestation Guardrail - Enforces non-bypassable, kernel-level cryptographic identity verification across Kubernetes microservices using Cilium eBPF and SPIRE. Eliminates sidecar proxy CPU, memory, and latency overheads by delegating mutual workload attestation and mTLS handshakes directly to the node-level eBPF socket layer.
globs: k8s/**/*.yaml, deploy/**/*.yaml, helm/**/*.yaml, charts/**/*.yaml, infrastructure/**/*.tf
alwaysApply: true
verified_by: "agentrules.org"
license: "CC-BY-4.0"
source: "https://agentrules.org/rules/cilium-ebpf-sidecarless-spiffe-attestation-guardrail"
---

# eBPF Cilium Sidecarless SPIFFE Workload Identity Attestation Guardrail

> **Severity**: CRITICAL | **Category**: devops
> **Anti-Pattern Warning**: Injecting Per-Pod Envoy Sidecars and Insecure Host-IP Network Policies Lacking Cryptographic Identity

## System Constraints
You are a Principal DevOps and Security Architect enforcing sidecarless zero-trust architecture using Cilium eBPF and SPIFFE/SPIRE. You strictly reject vulnerable sidecar proxy injections, raw IP/CIDR-based network policies, and unauthenticated inter-service socket interactions in favor of non-bypassable kernel-level cryptographic identity attestation.

## Strict Guidelines
- Engineers MUST ALWAYS declare CiliumNetworkPolicy (CNP) or CiliumClusterwideNetworkPolicy (CCNP) with explicit SPIFFE ID authentication modes (`authentication.mode: test-ticker` / `authentication.mode: spiffe`).
- Engineers MUST NOT inject per-pod Envoy or service-mesh sidecar containers (e.g., Istio/Linkerd classic sidecars), mandating ambient/node-level eBPF socket enforcement to eliminate latency and L4-L7 hop overhead.
- Services MUST attest identities through the node-local SPIRE agent via Unix Domain Socket mounted securely from the host, mapping cgroupv2 and pod UID to the verified SPIFFE ID.
- Engineers MUST NEVER rely on Kubernetes IP addresses, Pod labels, or standard L3/L4 NetworkPolicies for zero-trust authorization, as IP address churn and spoofing invalidate cryptographic guarantees.
- Cilium Helm configurations MUST enable mutual authentication (`authentication.mutual.spire.enabled: true`) and configure the SPIRE agent integration endpoint explicitly.

## Bad vs Good Implementations
### Cilium Sidecarless SPIFFE Attestation vs Legacy Sidecar Proxy with Label Policy

#### Bad Antipattern (AI Common Hallucination)
> **Why it fails**: Injects heavy per-pod proxy sidecars (wasting 0.5-1 CPU core and hundreds of MBs of RAM per pod) and uses standard Kubernetes NetworkPolicies that rely solely on mutable pod labels and dynamic IP allocation rather than verified cryptographic identity.
```yaml
# INSECURE: Relies on sidecar injection, mutable pod labels, and bypassable IP network policy
apiVersion: apps/v1
kind: Deployment
metadata:
  name: payment-service
spec:
  template:
    metadata:
      annotations:
        sidecar.istio.io/inject: "true"
      labels:
        app: payment-service
    spec:
      containers:
        - name: payment
          image: payment-service:v2.1.0
---
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-checkout-to-payment
spec:
  podSelector:
    matchLabels:
      app: payment-service
  ingress:
    - from:
        - podSelector:
            matchLabels:
              app: checkout-service # Trivially spoofed via pod label tampering
```

#### Production Standard (Correct)
> **Standard**: Enforces non-bypassable eBPF kernel-level socket matching combined with SPIFFE identity attestation via node-local SPIRE. Traffic is cryptographically authenticated and authorized at the socket layer without per-pod sidecars, eliminating proxy resource overhead and latency.
```yaml
# SECURE & OPTIMIZED: Sidecarless eBPF Kernel-Enforced SPIFFE Attestation Policy
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
  name: secure-payment-spiffe-auth
  namespace: payments
spec:
  endpointSelector:
    matchLabels:
      app.kubernetes.io/name: payment-service
  ingress:
    - fromEndpoints:
        - matchLabels:
            app.kubernetes.io/name: checkout-service
            io.kubernetes.pod.namespace: checkout
      authentication:
        mode: spiffe
      toPorts:
        - ports:
            - port: "8443"
              protocol: TCP
          rules:
            http:
              - method: POST
                path: "/v1/charge"
```
Recommended MCP Servers (mcp-serverlist.com)

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

Cilium Cluster Diagnostics MCP
Validates eBPF datapaths, SPIFFE authentication maps, and sidecarless mesh connectivity.
SPIRE Workload Attestation MCP
Inspects SPIFFE SVIs, registration entries, and cgroup-to-identity node attestations.
Recommended Agent Skills (askills.dev)

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

Cilium Policy and Mutual Auth Validator
Verifies that all CiliumNetworkPolicies enforce mutual SPIFFE authentication modes without legacy sidecar injection.
Architectural Specification & Invariant Rationale

Architectural Invariant Design: eBPF Cilium Sidecarless SPIFFE Workload Identity Attestation Guardrail

eBPF Cilium Sidecarless SPIFFE Workload Identity Attestation Guardrail defines an industrial-grade behavioral standard for devops engineering. Enforces non-bypassable, kernel-level cryptographic identity verification across Kubernetes microservices using Cilium eBPF and SPIRE. Eliminates sidecar proxy CPU, memory, and latency overheads by delegating mutual workload attestation and mTLS handshakes directly to the node-level eBPF socket layer. 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: Injecting Per-Pod Envoy Sidecars and Insecure Host-IP Network Policies Lacking Cryptographic Identity 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 DriftInjecting Per-Pod Envoy Sidecars and Insecure Host-IP Network Policies Lacking Cryptographic IdentityCritical
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 declare CiliumNetworkPolicy (CNP) or CiliumClusterwideNetworkPolicy (CCNP) with explicit SPIFFE ID authentication modes (`authentication.mode

Engineers MUST ALWAYS declare CiliumNetworkPolicy (CNP) or CiliumClusterwideNetworkPolicy (CCNP) with explicit SPIFFE ID authentication modes (`authentication.mode: test-ticker` / `authentication.mode: spiffe`).

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 per-pod Envoy or service-mesh sidecar containers (e.g., Istio/Linkerd classic sidecars), mandating ambient/node-level eBPF socket enforcement to eliminate latency and L4-L7 hop overhead.

Engineers MUST NOT inject per-pod Envoy or service-mesh sidecar containers (e.g., Istio/Linkerd classic sidecars), mandating ambient/node-level eBPF socket enforcement to eliminate latency and L4-L7 hop overhead.

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 attest identities through the node-local SPIRE agent via Unix Domain Socket mounted securely from the host, mapping cgroupv2 and pod UID to the verified SPIFFE ID.

Services MUST attest identities through the node-local SPIRE agent via Unix Domain Socket mounted securely from the host, mapping cgroupv2 and pod UID to the verified SPIFFE ID.

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 NEVER rely on Kubernetes IP addresses, Pod labels, or standard L3/L4 NetworkPolicies for zero-trust authorization, as IP address churn and spoofing invalidate cryptographic guarantees.

Engineers MUST NEVER rely on Kubernetes IP addresses, Pod labels, or standard L3/L4 NetworkPolicies for zero-trust authorization, as IP address churn and spoofing invalidate cryptographic guarantees.

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

Cilium Helm configurations MUST enable mutual authentication (`authentication.mutual.spire.enabled

Cilium Helm configurations MUST enable mutual authentication (`authentication.mutual.spire.enabled: true`) and configure the SPIRE agent integration endpoint explicitly.

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 eBPF Cilium Sidecarless SPIFFE Workload Identity Attestation Guardrail critical for AI coding assistants?

Enforces non-bypassable, kernel-level cryptographic identity verification across Kubernetes microservices using Cilium eBPF and SPIRE. Eliminates sidecar proxy CPU, memory, and latency overheads by delegating mutual workload attestation and mTLS handshakes directly to the node-level eBPF socket layer. 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 (Injecting Per-Pod Envoy Sidecars and Insecure Host-IP Network Policies Lacking Cryptographic Identity) 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.

Open Specification · CC BY 4.0·Free for Personal, Team & Commercial In-Repo Use

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This specification is licensed under Creative Commons Attribution 4.0 International (CC BY 4.0). You are completely free to adapt and share this rule in your workspace. If citing, including in public AI benchmark datasets, or redistributing, attribution to AgentRules.org is required.

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