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

Cilium Sidecarless Mesh SPIFFE/SPIRE Cryptographic Identity Invariant

Mandates sidecarless eBPF-accelerated transport and cryptographic workload attestation using SPIFFE/SPIRE in Cilium Service Mesh. Eliminates per-pod Envoy sidecar memory and latency overhead by enforcing kernel-level socket redirection and mutual TLS with SPIFFE ID SAN validation natively via CiliumNetworkPolicies.

Prohibited Anti-Pattern: Injecting Inefficient Sidecar Proxies or Permitting Unauthenticated Kernel Socket Traversal via IP-Only CIDR Policies

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---
description: Cilium Sidecarless Mesh SPIFFE/SPIRE Cryptographic Identity Invariant - Mandates sidecarless eBPF-accelerated transport and cryptographic workload attestation using SPIFFE/SPIRE in Cilium Service Mesh. Eliminates per-pod Envoy sidecar memory and latency overhead by enforcing kernel-level socket redirection and mutual TLS with SPIFFE ID SAN validation natively via CiliumNetworkPolicies.
globs: k8s/**/*.yaml, k8s/**/*.yml, deploy/**/*.yaml, deploy/**/*.yml, helm/**/*.yaml, helm/**/*.yml, infra/**/*.tf
alwaysApply: true
verified_by: "agentrules.org"
license: "CC-BY-4.0"
source: "https://agentrules.org/rules/cilium-ebpf-sidecarless-spiffe-attestation"
---

# Cilium Sidecarless Mesh SPIFFE/SPIRE Cryptographic Identity Invariant

> **Severity**: CRITICAL | **Category**: devops
> **Anti-Pattern Warning**: Injecting Inefficient Sidecar Proxies or Permitting Unauthenticated Kernel Socket Traversal via IP-Only CIDR Policies

## System Constraints
You are a Principal Systems & Cloud-Native Security Architect enforcing eBPF Cilium Sidecarless Ambient Mesh with SPIFFE/SPIRE Identity Attestation. You must mandate zero-sidecar architectures using kernel-native eBPF socket redirection (sockops) and strict cryptographic L7 mTLS identity verification. Reject any configuration that relies purely on mutable IP/CIDR matching or introduces per-pod proxy wrappers that defeat kernel-bypass latency guarantees.

## Strict Guidelines
- Engineers MUST ALWAYS enforce mutual authentication in CiliumNetworkPolicy resources using the authentication.mutual stanza backed by SPIRE-issued certificates.
- Engineers MUST NOT deploy per-pod Envoy sidecar proxy containers when Cilium Ambient L7 capabilities are enabled on the cluster nodes.
- Services MUST attest their identity strictly through the node-local SPIRE Agent Unix Domain Socket (/run/spire/sockets/agent.sock) using Linux kernel cgroup and UID/GID attestation.
- Components NEVER accept incoming L7 traffic without cryptographically matching the exact SPIFFE ID URI format (spiffe://<trust-domain>/ns/<namespace>/sa/<serviceaccount>).
- Code SHOULD leverage Cilium's eBPF host-proxy daemon mode solely for policy termination where L7 inspections are mandated, preserving L4 kernel-space bypass for all intra-node flows.

## Bad vs Good Implementations
### Cilium Network Policy Identity Enforcement (Sidecarless SPIFFE vs Insecure L3/L4 Label Match)

#### Bad Antipattern (AI Common Hallucination)
> **Why it fails**: This policy relies entirely on Kubernetes pod labels and kernel IP tracking without mutual cryptographic attestation. An attacker with pod-exec privileges or IP reuse exploitation can bypass this boundary without presenting a verified SPIFFE cryptographic identity.
```yaml
apiVersion: "cilium.io/v2"
kind: CiliumNetworkPolicy
metadata:
  name: secure-payment-ingress
  namespace: payments
spec:
  endpointSelector:
    matchLabels:
      app: payment-gateway
  ingress:
  - fromEndpoints:
    # VULNERABLE: Relies strictly on Kubernetes labels susceptible to spoofing and IP recycling
    - matchLabels:
        app: checkout-service
    toPorts:
    - ports:
      - port: "8443"
        protocol: TCP
```

#### Production Standard (Correct)
> **Standard**: Enforces Cilium's mutual authentication handshake backed by node-level SPIRE agents. Traffic is transparently accelerated in the kernel via eBPF while requiring an attested SPIFFE ID before socket connection establishment.
```yaml
apiVersion: "cilium.io/v2"
kind: CiliumNetworkPolicy
metadata:
  name: secure-payment-ingress
  namespace: payments
spec:
  endpointSelector:
    matchLabels:
      app: payment-gateway
  ingress:
  - fromEndpoints:
    - matchLabels:
        app: checkout-service
    # SECURE: Enforces kernel-mediated mTLS identity handshake via SPIFFE/SPIRE provider
    authentication:
      mode: "required"
    toPorts:
    - ports:
      - port: "8443"
        protocol: TCP
      rules:
        http:
        - method: "POST"
          path: "/v1/charge"
          headers:
          - "X-Forwarded-Client-Cert: .*URI=spiffe://prod.internal/ns/checkout/sa/checkout-service-sa.*"
```
Recommended MCP Servers (mcp-serverlist.com)

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

Kubernetes Cluster Inspector
Inspects running Cilium daemonsets, CiliumNetworkPolicies, and SPIRE agent daemonsets across Kubernetes clusters.
Recommended Agent Skills (askills.dev)

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

Cilium CLI Integration
Validates eBPF datapaths, endpoint identity assignments, and SPIFFE mutual authentication handshakes using 'cilium bpf' and 'cilium identity' tooling.
Architectural Specification & Invariant Rationale

Architectural Invariant Design: Cilium Sidecarless Mesh SPIFFE/SPIRE Cryptographic Identity Invariant

Cilium Sidecarless Mesh SPIFFE/SPIRE Cryptographic Identity Invariant defines an industrial-grade behavioral standard for devops engineering. Mandates sidecarless eBPF-accelerated transport and cryptographic workload attestation using SPIFFE/SPIRE in Cilium Service Mesh. Eliminates per-pod Envoy sidecar memory and latency overhead by enforcing kernel-level socket redirection and mutual TLS with SPIFFE ID SAN validation natively via CiliumNetworkPolicies. 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 Inefficient Sidecar Proxies or Permitting Unauthenticated Kernel Socket Traversal via IP-Only CIDR Policies 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 Inefficient Sidecar Proxies or Permitting Unauthenticated Kernel Socket Traversal via IP-Only CIDR PoliciesCritical
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 enforce mutual authentication in CiliumNetworkPolicy resources using the authentication.mutual stanza backed by SPIRE-issued certificates.

Engineers MUST ALWAYS enforce mutual authentication in CiliumNetworkPolicy resources using the authentication.mutual stanza backed by SPIRE-issued certificates.

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 deploy per-pod Envoy sidecar proxy containers when Cilium Ambient L7 capabilities are enabled on the cluster nodes.

Engineers MUST NOT deploy per-pod Envoy sidecar proxy containers when Cilium Ambient L7 capabilities are enabled on the 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.
3

Services MUST attest their identity strictly through the node-local SPIRE Agent Unix Domain Socket (/run/spire/sockets/agent.sock) using Linux kernel cgroup and UID/GID attestation.

Services MUST attest their identity strictly through the node-local SPIRE Agent Unix Domain Socket (/run/spire/sockets/agent.sock) using Linux kernel cgroup and UID/GID attestation.

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

Components NEVER accept incoming L7 traffic without cryptographically matching the exact SPIFFE ID URI format (spiffe

Components NEVER accept incoming L7 traffic without cryptographically matching the exact SPIFFE ID URI format (spiffe://<trust-domain>/ns/<namespace>/sa/<serviceaccount>).

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

Code SHOULD leverage Cilium's eBPF host-proxy daemon mode solely for policy termination where L7 inspections are mandated, preserving L4 kernel-space bypass for all intra-node flows.

Code SHOULD leverage Cilium's eBPF host-proxy daemon mode solely for policy termination where L7 inspections are mandated, preserving L4 kernel-space bypass for all intra-node flows.

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 Sidecarless Mesh SPIFFE/SPIRE Cryptographic Identity Invariant critical for AI coding assistants?

Mandates sidecarless eBPF-accelerated transport and cryptographic workload attestation using SPIFFE/SPIRE in Cilium Service Mesh. Eliminates per-pod Envoy sidecar memory and latency overhead by enforcing kernel-level socket redirection and mutual TLS with SPIFFE ID SAN validation natively via CiliumNetworkPolicies. 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 Inefficient Sidecar Proxies or Permitting Unauthenticated Kernel Socket Traversal via IP-Only CIDR Policies) 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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