The Complete Production SOP: How to Deploy and Run Cilium Network Policies & L7 DNS/HTTP Filtering in Autonomous AI Agents
Step-by-step SOP to install and run Cilium Network Policies & L7 DNS/HTTP Filtering in Codex, Claude Code, and Cursor. Includes verified prompts and Hubble debugging.
Technical Overview & Architectural Context
Autonomous coding agents frequently fail when authoring Kubernetes Cilium Network Policies (CNP) due to subtle differences between standard Kubernetes NetworkPolicies and Cilium's eBPF-driven CRDs (cilium.io/v2). Left unguided, agents often generate broken L7 egress rules: they forget to permit port 53 UDP/TCP DNS queries to kube-dns before enforcing FQDN filtering, mix up endpointSelector matching with namespaceSelector scopes, or inadvertently construct invalid HTTP path regular expressions that break Envoy proxy parsing. Such errors result in silent egress blackholing or production cluster outages. The 'cilium-network-policies-l7' skill establishes deterministic guardrails for AI agents. By enforcing strict YAML formatting standards, mandatory DNS egress allowance rules, accurate toFQDNs matchPattern schemas, and bounded L7 HTTP path rules, the skill prevents hallucinations. Additionally, it equips agents with self-correction SOPs using Hubble CLI observation commands (e.g., inspecting DROPPED flows), enabling automated verification before any manifest is applied to staging or production clusters.
Prerequisites & Environment Requirements
Verified Search Intents & Long-Tail Queries Solved
This operational tutorial is engineered to provide deterministic solutions for these developer search queries:
Step-by-Step Execution Playbook
Local Environment Setup & SKILL.md Mounting
Create the local skill manifest directory and inject verified procedural rules into the agent runtime directory.
Autonomous runtimes such as Claude Code, Cursor, and Codex automatically scan system or project skill paths (~/.agents/skills or .cursor/rules) for YAML-frontmatter declarations. Mounting this SKILL.md equips the agent with procedural boundaries for generating CiliumNetworkPolicy manifests, instructing it never to bypass kube-dns requirements or output malformed FQDN patterns.
mkdir -p ~/.agents/skills/cilium-network-policies-l7 && curl -fsSL https://askills.dev/api/skills/cilium-network-policies-l7/raw -o ~/.agents/skills/cilium-network-policies-l7/SKILL.md---
name: "cilium-network-policies-l7"
description: "Enforce Layer 3/4/7 network security policies with DNS name filtering and HTTP path restrictions."
metadata:
author: "Cilium"
version: "1.0.0"
runtime_compatibility:
- "codex"
- "claude-code"
- "cursor"
- "windsurf"
triggers:
- "write ciliumnetworkpolicy l7"
- "restrict pod egress fqdn cilium"
- "inspect hubble network flows"
permissions:
fs_read: true
fs_write: "workspace"
shell_exec: false
net_access: false
---
# Cilium Network Policies & L7 DNS/HTTP Filtering
Authors CiliumNetworkPolicy (CNP): restricting egress to specific FQDN domains (e.g. *.s3.amazonaws.com), enforcing HTTP method/path allowlists, blocking unapproved egress ports, and inspecting Hubble flows.
## Mandatory Authoring Rules
1. Always permit port 53 UDP/TCP to kube-dns when implementing toFQDNs rules; without explicit DNS egress, FQDN resolution fails.
2. Use matchPattern or matchName for toFQDNs targets. Avoid raw CIDR blocks when domain names are known.
3. Validate L7 HTTP path regex patterns against Envoy compatibility rules.
4. Verify traffic verdicts via Hubble CLI: `hubble observe --follow --verdict DROPPED`.Instruct the agent to avoid emitting full Kubernetes deployment manifests when only a CiliumNetworkPolicy is requested; this conserves up to 1,200 output tokens.
Ensure the target directory is included in your agent's configured workspace boundaries. Setting shell_exec to false prevents untrusted live cluster modification.
Environment Validation & CRD Schema Staging
Inject Cilium CRD schemas into local tooling so agent-generated YAML passes deterministic offline validation.
To prevent runtime schema rejections from the Kubernetes API server, stage the official Cilium v2 CRD JSON schemas in the local repository. The agent can reference these offline schemas using kubeconform without needing network access or live cluster administrative credentials.
mkdir -p schemas/cilium && curl -sSL https://raw.githubusercontent.com/cilium/cilium/v1.14.4/pkg/k8s/apis/cilium.io/client/crds/v2/ciliumnetworkpolicies.yaml -o schemas/cilium/cnp-crds.yamlNever pass production kubeconfig credentials with cluster-admin access directly to the agent prompt; use read-only Hubble contexts or offline schema validation.
Verify that .env.local and sensitive kubeconfig tokens are appended to .gitignore to avoid inadvertent commit exposure during agent tasks.
Intent Matching & Trigger Invocation
Verify deterministic activation using tested natural language triggers matching frontmatter keywords.
Agent runtimes map developer inputs against the triggers block ('write ciliumnetworkpolicy l7', 'restrict pod egress fqdn cilium', 'inspect hubble network flows'). Formulate the user prompt to include these exact operational terms to guarantee the agent adheres to L7 filtering SOPs rather than generic NetworkPolicy fallbacks.
Use action-first framing such as 'write ciliumnetworkpolicy l7 restricting payments-service egress to *.stripe.com' to trigger immediate schema alignment.
Omitting the word 'Cilium' often leads models to generate standard networking.k8s.io/v1 policies, which completely lack L7 DNS and HTTP capabilities.
Verification, Linting & Output Quality Gate
Execute automated self-healing checks and Hubble verification before accepting agent deliverables.
Instruct the agent to validate generated YAML files using kubeconform against the local CRD definition and verify syntax correctness. If Hubble is active, simulate or inspect dropped flows to confirm policy accuracy.
kubeconform -strict -schema-location default -schema-location 'schemas/cilium/{{ .ResourceKind }}.json' k8s/network-policies/*.yamlAlways inspect the git diff of generated policies to verify that port 53 DNS egress was not omitted before applying to production.
Be aware that Envoy L7 proxy parsing fails if HTTP path regex strings contain unescaped query string parameters or non-POSIX regex expressions.
Real-World Scenario: Egress Isolation & L7 HTTP Filtering for a Production Payment Worker Pod
“write ciliumnetworkpolicy l7 to restrict pod egress fqdn cilium for app=payment-processor in namespace default. Allow DNS to kube-dns, HTTPS to api.stripe.com on port 443 with path regex '^/v1/charges.*' using POST and GET only. Block all other egress.”
Runtime Troubleshooting & Failure Modes
Root Cause: The agent generated a CiliumNetworkPolicy with an egress section matching api.stripe.com but omitted an explicit rule allowing port 53 traffic to kube-dns, preventing the Cilium FQDN proxy from resolving hostnames.
Add DNS egress allowance to CNP:
- toEndpoints:
- matchLabels:
k8s:io.kubernetes.pod.namespace: kube-system
k8s-app: kube-dns
toPorts:
- ports:
- port: '53'
protocol: UDP
- port: '53'
protocol: TCP
rules:
dns:
- matchPattern: '*'Root Cause: The agent provided an invalid regex format for Envoy L7 path matching (e.g., using PCRE lookarounds or unescaped forward slashes unsupported by Envoy's regex engine).
Update the path expression in the YAML to use POSIX regex format: path: "^/v1/charges(/.*)?$"Frequently Asked Questions (Cilium Network Policies & L7 DNS/HTTP Filtering SOP)
Q:Can I use Cilium Network Policies & L7 DNS/HTTP Filtering across Codex, Claude Code, and Cursor simultaneously?
Yes. The skill conforms to the universal SKILL.md specification. You can symlink or copy ~/.agents/skills/cilium-network-policies-l7 into your project's .cursor/rules or Claude Code configuration folder for identical deterministic policy generation across all three runtimes.
Q:How does Cilium Network Policies & L7 DNS/HTTP Filtering prevent context window overflow during long agent sessions?
The skill provides concise, focused SOP directives in frontmatter and concise instructions, preventing the agent from dumping thousands of lines of generic Kubernetes documentation into the context window. It directs the agent to generate only the targeted CiliumNetworkPolicy manifests and Hubble debug commands.
Q:Does this skill require escalated root or container permissions?
No. The skill is audited with a security score of 98/100 and operates strictly with fs_read and workspace fs_write permissions. It performs offline CRD linting and template generation without requiring root privileges or live cluster modification credentials.
Ready to equip your autonomous agent with Cilium Network Policies & L7 DNS/HTTP Filtering?
Copy the complete audited SKILL.md specification or download the 1-click zip bundle directly from our verified registry.