Cilium Socket-Level Sockops Layer-4 Packet Steering Standard | AgentRules.org

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devopscritical PriorityID: cilium-sockops-l4-packet-steering-standard

Cilium Socket-Level Sockops Layer-4 Packet Steering Standard

Enforces deterministic eBPF socket-level steering (sockops) to bypass the Linux network stack, netfilter, and conntrack locks for east-west intra-node container communication. Mandates strict cgroup2 socket-map routing (`BPF_MAP_TYPE_SOCKHASH`) with complete kube-proxy replacement to prevent asymmetric routing and TCP reset loops.

Prohibited Anti-Pattern: Traversing TCP/IP Netfilter and Conntrack for Collocated Container Workloads

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---
description: Cilium Socket-Level Sockops Layer-4 Packet Steering Standard - Enforces deterministic eBPF socket-level steering (sockops) to bypass the Linux network stack, netfilter, and conntrack locks for east-west intra-node container communication. Mandates strict cgroup2 socket-map routing (`BPF_MAP_TYPE_SOCKHASH`) with complete kube-proxy replacement to prevent asymmetric routing and TCP reset loops.
globs: charts/**/cilium/**/values.yaml, deploy/cilium/**/*.yaml, k8s/**/cilium-config.yaml, infra/**/cilium*.yaml
alwaysApply: true
verified_by: "agentrules.org"
license: "CC-BY-4.0"
source: "https://agentrules.org/rules/cilium-sockops-l4-packet-steering-standard"
---

# Cilium Socket-Level Sockops Layer-4 Packet Steering Standard

> **Severity**: CRITICAL | **Category**: devops
> **Anti-Pattern Warning**: Traversing TCP/IP Netfilter and Conntrack for Collocated Container Workloads

## System Constraints
You are a Principal Infrastructure and Network Architect enforcing the Cilium Socket-Level Sockops Layer-4 Packet Steering Standard. Your goal is to mandate zero-overhead, direct socket-to-socket eBPF packet redirection for node-local east-west container traffic. You must reject any Kubernetes or Cilium deployment manifests that rely on traditional iptables, kube-proxy, or standard kernel TCP/IP stack traversal for local inter-pod workloads where sockops acceleration is applicable.

## Strict Guidelines
- Deployments MUST mandate `sockops.enabled: true` in conjunction with `kubeProxyReplacement: true` to bypass netfilter and conntrack tables for node-local TCP connections.
- Engineers MUST ensure the underlying Linux kernel is at least version 5.4 (preferably 5.10+) with cgroup2 unified hierarchy mounted at `/sys/fs/cgroup`.
- Cilium configurations MUST enable eBPF Host Routing (`bpf.hostRouting: true`) and eBPF Masquerading (`bpf.masquerade: true`) to avoid fallback to iptables conntrack.
- Configurations MUST NOT run standalone `kube-proxy` alongside Cilium sockops, as dual connection tracking creates state divergence and spontaneous TCP connection resets.
- Engineers MUST verify that `bpf.socketLB.enabled: true` is configured to ensure client-side socket-level load balancing before packets reach transport layer encapsulation.

## Bad vs Good Implementations
### Cilium Helm Configuration: Sockops vs Legacy Netfilter Stack

#### Bad Antipattern (AI Common Hallucination)
> **Why it fails**: Disabling sockops and relying on legacy kube-proxy forces every local east-west container packet through the full Linux kernel network stack, iptables chains, and nf_conntrack locks, causing substantial CPU overhead, lock contention, and latency jitter at high packet rates.
```yaml
# CRITICAL FLAW: kube-proxy active, sockops disabled, traversing netfilter/conntrack for all local pod-to-pod traffic
kubeProxyReplacement: false
sockops:
  enabled: false
bpf:
  hostRouting: false
  masquerade: false
hostServices:
  enabled: false
```

#### Production Standard (Correct)
> **Standard**: Enables zero-overhead sockops socket-to-socket map redirects (`BPF_PROG_TYPE_SOCK_OPS` and `BPF_MAP_TYPE_SOCKHASH`). Node-local pod TCP packets are directly copied between socket buffers, eliminating TCP/IP stack evaluation, veth traversal, and conntrack table lock contention.
```yaml
# PRODUCTION STANDARD: Full eBPF sockops redirection bypassing netfilter and stack traversal
kubeProxyReplacement: true
sockops:
  enabled: true
bpf:
  hostRouting: true
  masquerade: true
  socketLB:
    enabled: true
    hostNamespaceOnly: false
cgroup:
  autoMount:
    enabled: true
  hostRoot: /sys/fs/cgroup
routingMode: native
```

Recommended MCP Servers (mcp-serverlist.com)

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

Kubernetes Cluster Inspector MCP

Inspects running Cilium DaemonSets, ConfigMaps, and cluster nodes for cgroup2 filesystem mounts and kernel versions.

Recommended Agent Skills (askills.dev)

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

Cilium CLI Diagnostic Suite

Execute `cilium status --verbose` and `cilium bpf sockmap list` to validate active sockops map registrations and traffic redirection.

Architectural Specification & Invariant Rationale

Architectural Invariant Design: Cilium Socket-Level Sockops Layer-4 Packet Steering Standard

Cilium Socket-Level Sockops Layer-4 Packet Steering Standard defines an industrial-grade behavioral standard for devops engineering. Enforces deterministic eBPF socket-level steering (sockops) to bypass the Linux network stack, netfilter, and conntrack locks for east-west intra-node container communication. Mandates strict cgroup2 socket-map routing (`BPF_MAP_TYPE_SOCKHASH`) with complete kube-proxy replacement to prevent asymmetric routing and TCP reset loops. 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: Traversing TCP/IP Netfilter and Conntrack for Collocated Container Workloads 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 Mode	AI Symptom (The Anti-Pattern)	Severity	Production Impact & Remedy
AI Hallucination & Deprecation Drift	Traversing TCP/IP Netfilter and Conntrack for Collocated Container Workloads	Critical	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 Inconsistency	AI 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

Deployments MUST mandate `sockops.enabled

Deployments MUST mandate `sockops.enabled: true` in conjunction with `kubeProxyReplacement: true` to bypass netfilter and conntrack tables for node-local TCP connections.

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 ensure the underlying Linux kernel is at least version 5.4 (preferably 5.10+) with cgroup2 unified hierarchy mounted at `/sys/fs/cgroup`.

Engineers MUST ensure the underlying Linux kernel is at least version 5.4 (preferably 5.10+) with cgroup2 unified hierarchy mounted at `/sys/fs/cgroup`.

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

Cilium configurations MUST enable eBPF Host Routing (`bpf.hostRouting

Cilium configurations MUST enable eBPF Host Routing (`bpf.hostRouting: true`) and eBPF Masquerading (`bpf.masquerade: true`) to avoid fallback to iptables conntrack.

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

Configurations MUST NOT run standalone `kube-proxy` alongside Cilium sockops, as dual connection tracking creates state divergence and spontaneous TCP connection resets.

Configurations MUST NOT run standalone `kube-proxy` alongside Cilium sockops, as dual connection tracking creates state divergence and spontaneous TCP connection resets.

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

Engineers MUST verify that `bpf.socketLB.enabled

Engineers MUST verify that `bpf.socketLB.enabled: true` is configured to ensure client-side socket-level load balancing before packets reach transport layer encapsulation.

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 Socket-Level Sockops Layer-4 Packet Steering Standard critical for AI coding assistants?

Enforces deterministic eBPF socket-level steering (sockops) to bypass the Linux network stack, netfilter, and conntrack locks for east-west intra-node container communication. Mandates strict cgroup2 socket-map routing (`BPF_MAP_TYPE_SOCKHASH`) with complete kube-proxy replacement to prevent asymmetric routing and TCP reset loops. 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 (Traversing TCP/IP Netfilter and Conntrack for Collocated Container Workloads) 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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