Cilium & Hubble Network Observability

Manage eBPF-based networking using kubectl-mcp-server's Cilium tools (8 tools).

When to Apply

Use this skill when:

• User mentions: "Cilium", "Hubble", "eBPF", "network policy", "flow"
• Operations: network policy management, traffic observation, L7 filtering
• Keywords: "network security", "traffic flow", "dropped packets", "connectivity"

Priority Rules

Priority	Rule	Impact	Tools
1	Detect Cilium installation first	CRITICAL	cilium_detect_tool
2	Check agent status for health	HIGH	cilium_status_tool
3	Use Hubble for flow debugging	HIGH	hubble_flows_query_tool
4	Start with default deny	MEDIUM	CiliumNetworkPolicy

Quick Reference

Task	Tool	Example
Detect Cilium	cilium_detect_tool	cilium_detect_tool()
Agent status	cilium_status_tool	cilium_status_tool()
List policies	cilium_policies_list_tool	cilium_policies_list_tool(namespace)
Query flows	hubble_flows_query_tool	hubble_flows_query_tool(namespace)

Check Installation

cilium_detect_tool()

Cilium Status

cilium_status_tool()

Network Policies

List Policies

cilium_policies_list_tool(namespace="default")

Get Policy Details

cilium_policy_get_tool(name="allow-web", namespace="default")

Create Cilium Network Policy

kubectl_apply(manifest="""
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
  name: allow-web
  namespace: default
spec:
  endpointSelector:
    matchLabels:
      app: web
  ingress:
  - fromEndpoints:
    - matchLabels:
        app: frontend
    toPorts:
    - ports:
      - port: "80"
        protocol: TCP
  egress:
  - toEndpoints:
    - matchLabels:
        app: database
    toPorts:
    - ports:
      - port: "5432"
        protocol: TCP
""")

Endpoints

cilium_endpoints_list_tool(namespace="default")

Identities

cilium_identities_list_tool()

Nodes

cilium_nodes_list_tool()

Hubble Flow Observability

hubble_flows_query_tool(
    namespace="default",
    pod="my-pod",
    last="5m"
)

hubble_flows_query_tool(
    namespace="default",
    verdict="DROPPED"
)

hubble_flows_query_tool(
    namespace="default",
    type="l7"
)

Create L7 Policy

kubectl_apply(manifest="""
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
  name: api-policy
  namespace: default
spec:
  endpointSelector:
    matchLabels:
      app: api
  ingress:
  - fromEndpoints:
    - matchLabels:
        app: frontend
    toPorts:
    - ports:
      - port: "8080"
        protocol: TCP
      rules:
        http:
        - method: GET
          path: "/api/v1/.*"
        - method: POST
          path: "/api/v1/users"
""")

Cluster Mesh

kubectl_apply(manifest="""
apiVersion: cilium.io/v2
kind: CiliumClusterwideNetworkPolicy
metadata:
  name: allow-cross-cluster
spec:
  endpointSelector:
    matchLabels:
      app: shared-service
  ingress:
  - fromEntities:
    - cluster
    - remote-node
""")

Troubleshooting Workflows

Pod Can't Reach Service

cilium_status_tool()
cilium_endpoints_list_tool(namespace)
cilium_policies_list_tool(namespace)
hubble_flows_query_tool(namespace, pod, verdict="DROPPED")

Policy Not Working

cilium_policy_get_tool(name, namespace)
cilium_endpoints_list_tool(namespace)
hubble_flows_query_tool(namespace)

Network Performance Issues

cilium_status_tool()
cilium_nodes_list_tool()
hubble_flows_query_tool(namespace, type="l7")

Best Practices

1. Start with default deny: Create baseline deny-all policy
2. Use labels consistently: Policies rely on label selectors
3. Monitor with Hubble: Observe flows before/after policy changes
4. Test in staging: Verify policies don't break connectivity

Prerequisites

• Cilium: Required for all Cilium tools

  cilium install

Related Skills

• k8s-networking - Standard K8s networking
• k8s-security - Security policies
• k8s-service-mesh - Istio service mesh