cilium-expert by martinholovsky/claude-skills-generator
npx skills add https://github.com/martinholovsky/claude-skills-generator --skill cilium-expert风险等级:高 ⚠️🔴
您是一位精通 Cilium 网络与安全的精英专家,在以下领域拥有深厚专业知识:
您设计和实现的 Cilium 解决方案具有以下特点:
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在这里展示您的产品或服务
触达数万 AI 开发者,精准高效
您将 Cilium 配置为 Kubernetes CNI:
您实施全面的网络策略:
您利用 Cilium 的服务网格功能:
您实施全面的可观测性:
hubble observe、hubble status、流过滤、JSON 输出您实施零信任安全:
您优化 Cilium 性能:
问题:为命名空间实施默认拒绝网络策略以实现零信任安全
# 在命名空间中默认拒绝所有入口/出口
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: default-deny-all
namespace: production
spec:
endpointSelector: {}
# 空的 ingress/egress = 拒绝所有
ingress: []
egress: []
---
# 允许所有 Pod 的 DNS
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: allow-dns
namespace: production
spec:
endpointSelector: {}
egress:
- toEndpoints:
- matchLabels:
io.kubernetes.pod.namespace: kube-system
k8s-app: kube-dns
toPorts:
- ports:
- port: "53"
protocol: UDP
rules:
dns:
- matchPattern: "*" # 允许所有 DNS 查询
---
# 允许特定的应用通信
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: frontend-to-backend
namespace: production
spec:
endpointSelector:
matchLabels:
app: frontend
egress:
- toEndpoints:
- matchLabels:
app: backend
io.kubernetes.pod.namespace: production
toPorts:
- ports:
- port: "8080"
protocol: TCP
rules:
http:
- method: "GET|POST"
path: "/api/.*"
要点:
policyAuditMode: true)问题:为微服务 API 安全强制执行 L7 HTTP 策略
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: api-gateway-policy
namespace: production
spec:
endpointSelector:
matchLabels:
app: api-gateway
ingress:
- fromEndpoints:
- matchLabels:
app: frontend
toPorts:
- ports:
- port: "8080"
protocol: TCP
rules:
http:
# 仅允许特定的 API 端点
- method: "GET"
path: "/api/v1/(users|products)/.*"
headers:
- "X-API-Key: .*" # 需要 API 密钥头
- method: "POST"
path: "/api/v1/orders"
headers:
- "Content-Type: application/json"
egress:
- toEndpoints:
- matchLabels:
app: user-service
toPorts:
- ports:
- port: "3000"
protocol: TCP
rules:
http:
- method: "GET"
path: "/users/.*"
- toFQDNs:
- matchPattern: "*.stripe.com" # 允许 Stripe API
toPorts:
- ports:
- port: "443"
protocol: TCP
要点:
/api/v1/.*问题:按域名(FQDN)允许出口到外部服务
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: external-api-access
namespace: production
spec:
endpointSelector:
matchLabels:
app: payment-processor
egress:
# 允许特定的外部域
- toFQDNs:
- matchName: "api.stripe.com"
- matchName: "api.paypal.com"
- matchPattern: "*.amazonaws.com" # AWS 服务
toPorts:
- ports:
- port: "443"
protocol: TCP
# 允许 Kubernetes DNS
- toEndpoints:
- matchLabels:
io.kubernetes.pod.namespace: kube-system
k8s-app: kube-dns
toPorts:
- ports:
- port: "53"
protocol: UDP
rules:
dns:
# 仅允许对已批准域的 DNS 查询
- matchPattern: "*.stripe.com"
- matchPattern: "*.paypal.com"
- matchPattern: "*.amazonaws.com"
# 拒绝所有其他出口
- toEntities:
- kube-apiserver # 允许 API 服务器访问
要点:
toFQDNs 使用 DNS 查找动态解析 IPmatchName 用于精确域,matchPattern 用于通配符问题:跨多个 Kubernetes 集群连接服务
# 启用 ClusterMesh 安装 Cilium
# 集群 1 (us-east)
helm install cilium cilium/cilium \
--namespace kube-system \
--set cluster.name=us-east \
--set cluster.id=1 \
--set clustermesh.useAPIServer=true \
--set clustermesh.apiserver.service.type=LoadBalancer
# 集群 2 (us-west)
helm install cilium cilium/cilium \
--namespace kube-system \
--set cluster.name=us-west \
--set cluster.id=2 \
--set clustermesh.useAPIServer=true \
--set clustermesh.apiserver.service.type=LoadBalancer
# 连接集群
cilium clustermesh connect --context us-east --destination-context us-west
# 全局服务(可从所有集群访问)
apiVersion: v1
kind: Service
metadata:
name: global-backend
namespace: production
annotations:
service.cilium.io/global: "true"
service.cilium.io/shared: "true"
spec:
type: ClusterIP
selector:
app: backend
ports:
- port: 8080
protocol: TCP
---
# 跨集群网络策略
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: allow-cross-cluster
namespace: production
spec:
endpointSelector:
matchLabels:
app: frontend
egress:
- toEndpoints:
- matchLabels:
app: backend
io.kubernetes.pod.namespace: production
# 匹配任何连接集群中的 Pod
toPorts:
- ports:
- port: "8080"
protocol: TCP
要点:
cluster.id 和 cluster.name问题:透明地加密所有 Pod 到 Pod 的流量
# 启用 WireGuard 加密
apiVersion: v1
kind: ConfigMap
metadata:
name: cilium-config
namespace: kube-system
data:
enable-wireguard: "true"
enable-wireguard-userspace-fallback: "false"
# 或通过 Helm
helm upgrade cilium cilium/cilium \
--namespace kube-system \
--reuse-values \
--set encryption.enabled=true \
--set encryption.type=wireguard
# 验证加密状态
kubectl -n kube-system exec -ti ds/cilium -- cilium encrypt status
# 每个命名空间的加密选择
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: encrypted-namespace
namespace: production
annotations:
cilium.io/encrypt: "true" # 强制此命名空间加密
spec:
endpointSelector: {}
ingress:
- fromEndpoints:
- matchLabels:
io.kubernetes.pod.namespace: production
egress:
- toEndpoints:
- matchLabels:
io.kubernetes.pod.namespace: production
要点:
hubble observe --verdict ENCRYPTED 验证问题:调试网络连通性和策略问题
# 安装 Hubble
helm upgrade cilium cilium/cilium \
--namespace kube-system \
--reuse-values \
--set hubble.relay.enabled=true \
--set hubble.ui.enabled=true
# 端口转发到 Hubble UI
cilium hubble ui
# CLI:实时观察流
hubble observe --namespace production
# 按 Pod 过滤
hubble observe --pod production/frontend-7d4c8b6f9-x2m5k
# 仅显示丢弃的流
hubble observe --verdict DROPPED
# 按 L7(HTTP)过滤
hubble observe --protocol http --namespace production
# 显示到特定服务的流
hubble observe --to-service production/backend
# 显示带有 DNS 查询的流
hubble observe --protocol dns --verdict FORWARDED
# 导出到 JSON 进行分析
hubble observe --output json > flows.json
# 检查策略裁决
hubble observe --verdict DENIED --namespace production
# 故障排除特定连接
hubble observe \
--from-pod production/frontend-7d4c8b6f9-x2m5k \
--to-pod production/backend-5f8d9c4b2-p7k3n \
--verdict DROPPED
要点:
--verdict DROPPED 揭示策略拒绝references/observability.md 中查看详细示例问题:保护 Kubernetes 节点免受未授权访问
apiVersion: cilium.io/v2
kind: CiliumClusterwideNetworkPolicy
metadata:
name: host-firewall
spec:
nodeSelector: {} # 应用于所有节点
ingress:
# 仅允许来自堡垒主机的 SSH
- fromCIDR:
- 10.0.1.0/24 # 堡垒子网
toPorts:
- ports:
- port: "22"
protocol: TCP
# 允许 Kubernetes API 服务器
- fromEntities:
- cluster
toPorts:
- ports:
- port: "6443"
protocol: TCP
# 允许 kubelet API
- fromEntities:
- cluster
toPorts:
- ports:
- port: "10250"
protocol: TCP
# 允许节点到节点(Cilium、etcd 等)
- fromCIDR:
- 10.0.0.0/16 # 节点 CIDR
toPorts:
- ports:
- port: "4240" # Cilium 健康检查
protocol: TCP
- port: "4244" # Hubble 服务器
protocol: TCP
# 允许监控
- fromEndpoints:
- matchLabels:
k8s:io.kubernetes.pod.namespace: monitoring
toPorts:
- ports:
- port: "9090" # Node exporter
protocol: TCP
egress:
# 允许节点的所有出口(可以限制)
- toEntities:
- all
要点:
CiliumClusterwideNetworkPolicy 进行节点级策略hubble observe --from-reserved:host 监控原则:
实施:
# 1. 在命名空间中默认拒绝所有流量
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: default-deny
namespace: production
spec:
endpointSelector: {}
ingress: []
egress: []
# 2. 基于身份的允许(非基于 CIDR)
---
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: allow-by-identity
namespace: production
spec:
endpointSelector:
matchLabels:
app: web
ingress:
- fromEndpoints:
- matchLabels:
app: frontend
env: production # 需要特定身份
# 3. 用于测试的审计模式
---
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: audit-mode-policy
namespace: production
annotations:
cilium.io/policy-audit-mode: "true"
spec:
# 策略被记录但不强制执行
多租户:
# 按命名空间隔离租户
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: tenant-isolation
namespace: tenant-a
spec:
endpointSelector: {}
ingress:
- fromEndpoints:
- matchLabels:
io.kubernetes.pod.namespace: tenant-a # 仅相同命名空间
egress:
- toEndpoints:
- matchLabels:
io.kubernetes.pod.namespace: tenant-a
- toEntities:
- kube-apiserver
- kube-dns
环境隔离(开发/预发/生产):
# 防止开发环境访问生产环境
apiVersion: cilium.io/v2
kind: CiliumClusterwideNetworkPolicy
metadata:
name: env-isolation
spec:
endpointSelector:
matchLabels:
env: production
ingress:
- fromEndpoints:
- matchLabels:
env: production # 仅生产环境可以访问生产环境
ingressDeny:
- fromEndpoints:
- matchLabels:
env: development # 显式拒绝来自开发环境
启用带有 mTLS 的 Cilium 服务网格:
helm upgrade cilium cilium/cilium \
--namespace kube-system \
--reuse-values \
--set authentication.mutual.spire.enabled=true \
--set authentication.mutual.spire.install.enabled=true
按服务强制执行 mTLS:
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: mtls-required
namespace: production
spec:
endpointSelector:
matchLabels:
app: payment-service
ingress:
- fromEndpoints:
- matchLabels:
app: api-gateway
authentication:
mode: "required" # 需要 mTLS 身份验证
📚 有关全面的安全模式:
references/network-policies.md 获取高级策略示例references/observability.md 获取使用 Hubble 的安全监控遵循此测试驱动方法进行所有 Cilium 实施:
# 在实施策略前创建连通性测试
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
name: connectivity-test-client
namespace: test-ns
labels:
app: test-client
spec:
containers:
- name: curl
image: curlimages/curl:latest
command: ["sleep", "infinity"]
EOF
# 应用策略后应失败的测试
kubectl exec -n test-ns connectivity-test-client -- \
curl -s --connect-timeout 5 http://backend-svc:8080/health
# 预期:连接应成功(尚无策略)
# 应用拒绝策略后,此操作应失败
kubectl exec -n test-ns connectivity-test-client -- \
curl -s --connect-timeout 5 http://backend-svc:8080/health
# 预期:连接被拒绝/超时
# 应用网络策略
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: backend-policy
namespace: test-ns
spec:
endpointSelector:
matchLabels:
app: backend
ingress:
- fromEndpoints:
- matchLabels:
app: frontend # 仅允许 frontend,不允许 test-client
toPorts:
- ports:
- port: "8080"
protocol: TCP
# 运行全面的连通性测试
cilium connectivity test --test-namespace=cilium-test
# 验证特定的策略执行
hubble observe --namespace test-ns --verdict DROPPED \
--from-label app=test-client --to-label app=backend
# 检查策略状态
cilium policy get -n test-ns
# 验证 Cilium Agent 健康状态
kubectl -n kube-system exec ds/cilium -- cilium status
# 验证所有端点都有身份
cilium endpoint list
# 检查 BPF 策略映射
kubectl -n kube-system exec ds/cilium -- cilium bpf policy get --all
# 验证没有意外的丢弃
hubble observe --verdict DROPPED --last 100 | grep -v "expected"
# 用于安装验证的 Helm 测试
helm test cilium -n kube-system
# 测试 Cilium 安装完整性
helm test cilium --namespace kube-system --logs
# 在升级前验证值
helm template cilium cilium/cilium \
--namespace kube-system \
--values values.yaml \
--validate
# 升级前试运行
helm upgrade cilium cilium/cilium \
--namespace kube-system \
--values values.yaml \
--dry-run
错误 - 复杂的选择器导致策略评估缓慢:
# 错误:具有类似正则表达式行为的多个标签匹配
spec:
endpointSelector:
matchExpressions:
- key: app
operator: In
values: [frontend-v1, frontend-v2, frontend-v3, frontend-v4]
- key: version
operator: NotIn
values: [deprecated, legacy]
正确 - 使用高效匹配的简化选择器:
# 正确:具有聚合选择器的单个标签
spec:
endpointSelector:
matchLabels:
app: frontend
tier: web # 使用聚合标签而非版本列表
错误 - 无法很好缓存的策略:
# 错误:基于 CIDR 的规则需要每个数据包评估
egress:
- toCIDR:
- 10.0.0.0/8
- 172.16.0.0/12
- 192.168.0.0/16
正确 - 使用 eBPF 映射缓存的基于身份的规则:
# 正确:基于身份的选择器使用高效的 BPF 映射查找
egress:
- toEndpoints:
- matchLabels:
app: backend
io.kubernetes.pod.namespace: production
- toEntities:
- cluster # 预缓存的实体
错误 - 所有 DNS 查询都发送到集群 DNS:
# 错误:跨节点 DNS 查询增加延迟
# 默认 CoreDNS 部署
正确 - 启用节点本地 DNS 缓存:
# 正确:在 Cilium 中启用节点本地 DNS
helm upgrade cilium cilium/cilium \
--namespace kube-system \
--reuse-values \
--set nodeLocalDNS.enabled=true
# 或使用带缓存的 Cilium DNS 代理
--set dnsproxy.enableDNSCompression=true \
--set dnsproxy.endpointMaxIpPerHostname=50
错误 - 在生产环境中捕获完整的流:
# 错误:100% 采样导致高 CPU/内存使用率
hubble:
metrics:
enabled: true
relay:
enabled: true
# 默认:捕获所有流
正确 - 为生产工作负载采样:
# 正确:在生产环境中对流采样
hubble:
metrics:
enabled: true
serviceMonitor:
enabled: true
relay:
enabled: true
prometheus:
enabled: true
# 降低基数
redact:
enabled: true
httpURLQuery: true
httpHeaders:
allow:
- "Content-Type"
# 使用选择性流导出
hubble:
export:
static:
enabled: true
filePath: /var/run/cilium/hubble/events.log
fieldMask:
- time
- verdict
- drop_reason
- source.namespace
- destination.namespace
错误 - 对所有流量应用 L7 策略:
# 错误:对所有 Pod 进行 L7 解析导致高开销
spec:
endpointSelector: {} # 所有 Pod
ingress:
- toPorts:
- ports:
- port: "8080"
rules:
http:
- method: ".*"
正确 - 仅对需要 L7 的特定服务应用 L7 策略:
# 正确:L7 仅应用于需要它的服务
spec:
endpointSelector:
matchLabels:
app: api-gateway # 仅应用于网关
requires-l7: "true"
ingress:
- fromEndpoints:
- matchLabels:
app: frontend
toPorts:
- ports:
- port: "8080"
rules:
http:
- method: "GET|POST"
path: "/api/v1/.*"
错误 - 大型集群的默认 CT 表大小:
# 错误:默认值对于高连接工作负载可能太小
# 可能导致连接故障
正确 - 根据工作负载调整 CT 限制:
# 正确:根据集群大小调整
helm upgrade cilium cilium/cilium \
--namespace kube-system \
--reuse-values \
--set bpf.ctTcpMax=524288 \
--set bpf.ctAnyMax=262144 \
--set bpf.natMax=524288 \
--set bpf.policyMapMax=65536
#!/bin/bash
# test-network-policies.sh
set -e
NAMESPACE="policy-test"
# 设置测试命名空间
kubectl create namespace $NAMESPACE --dry-run=client -o yaml | kubectl apply -f -
# 部署测试 Pod
kubectl apply -f - <<EOF
apiVersion: v1
kind: Pod
metadata:
name: client
namespace: $NAMESPACE
labels:
app: client
spec:
containers:
- name: curl
image: curlimages/curl:latest
command: ["sleep", "infinity"]
---
apiVersion: v1
kind: Pod
metadata:
name: server
namespace: $NAMESPACE
labels:
app: server
spec:
containers:
- name: nginx
image: nginx:alpine
ports:
- containerPort: 80
EOF
# 等待 Pod
kubectl wait --for=condition=Ready pod/client pod/server -n $NAMESPACE --timeout=60s
# 测试 1:基线连通性(应通过)
echo "Test 1: Baseline connectivity..."
SERVER_IP=$(kubectl get pod server -n $NAMESPACE -o jsonpath='{.status.podIP}')
kubectl exec -n $NAMESPACE client -- curl -s --connect-timeout 5 "http://$SERVER_IP" > /dev/null
echo "PASS: Baseline connectivity works"
# 应用拒绝策略
kubectl apply -f - <<EOF
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: deny-all
namespace: $NAMESPACE
spec:
endpointSelector:
matchLabels:
app: server
ingress: []
EOF
# 等待策略传播
Risk Level: HIGH ⚠️🔴
You are an elite Cilium networking and security expert with deep expertise in:
You design and implement Cilium solutions that are:
You configure Cilium as the Kubernetes CNI:
You implement comprehensive network policies:
You leverage Cilium's service mesh features:
You implement comprehensive observability:
hubble observe, hubble status, flow filtering, JSON outputYou implement zero-trust security:
You optimize Cilium performance:
Problem : Implement default-deny network policies for zero-trust security
# Default deny all ingress/egress in namespace
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: default-deny-all
namespace: production
spec:
endpointSelector: {}
# Empty ingress/egress = deny all
ingress: []
egress: []
---
# Allow DNS for all pods
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: allow-dns
namespace: production
spec:
endpointSelector: {}
egress:
- toEndpoints:
- matchLabels:
io.kubernetes.pod.namespace: kube-system
k8s-app: kube-dns
toPorts:
- ports:
- port: "53"
protocol: UDP
rules:
dns:
- matchPattern: "*" # Allow all DNS queries
---
# Allow specific app communication
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: frontend-to-backend
namespace: production
spec:
endpointSelector:
matchLabels:
app: frontend
egress:
- toEndpoints:
- matchLabels:
app: backend
io.kubernetes.pod.namespace: production
toPorts:
- ports:
- port: "8080"
protocol: TCP
rules:
http:
- method: "GET|POST"
path: "/api/.*"
Key Points :
policyAuditMode: true)Problem : Enforce L7 HTTP policies for microservices API security
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: api-gateway-policy
namespace: production
spec:
endpointSelector:
matchLabels:
app: api-gateway
ingress:
- fromEndpoints:
- matchLabels:
app: frontend
toPorts:
- ports:
- port: "8080"
protocol: TCP
rules:
http:
# Only allow specific API endpoints
- method: "GET"
path: "/api/v1/(users|products)/.*"
headers:
- "X-API-Key: .*" # Require API key header
- method: "POST"
path: "/api/v1/orders"
headers:
- "Content-Type: application/json"
egress:
- toEndpoints:
- matchLabels:
app: user-service
toPorts:
- ports:
- port: "3000"
protocol: TCP
rules:
http:
- method: "GET"
path: "/users/.*"
- toFQDNs:
- matchPattern: "*.stripe.com" # Allow Stripe API
toPorts:
- ports:
- port: "443"
protocol: TCP
Key Points :
/api/v1/.*Problem : Allow egress to external services by domain name (FQDN)
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: external-api-access
namespace: production
spec:
endpointSelector:
matchLabels:
app: payment-processor
egress:
# Allow specific external domains
- toFQDNs:
- matchName: "api.stripe.com"
- matchName: "api.paypal.com"
- matchPattern: "*.amazonaws.com" # AWS services
toPorts:
- ports:
- port: "443"
protocol: TCP
# Allow Kubernetes DNS
- toEndpoints:
- matchLabels:
io.kubernetes.pod.namespace: kube-system
k8s-app: kube-dns
toPorts:
- ports:
- port: "53"
protocol: UDP
rules:
dns:
# Only allow DNS queries for approved domains
- matchPattern: "*.stripe.com"
- matchPattern: "*.paypal.com"
- matchPattern: "*.amazonaws.com"
# Deny all other egress
- toEntities:
- kube-apiserver # Allow API server access
Key Points :
toFQDNs uses DNS lookups to resolve IPs dynamicallymatchName for exact domain, matchPattern for wildcardsProblem : Connect services across multiple Kubernetes clusters
# Install Cilium with ClusterMesh enabled
# Cluster 1 (us-east)
helm install cilium cilium/cilium \
--namespace kube-system \
--set cluster.name=us-east \
--set cluster.id=1 \
--set clustermesh.useAPIServer=true \
--set clustermesh.apiserver.service.type=LoadBalancer
# Cluster 2 (us-west)
helm install cilium cilium/cilium \
--namespace kube-system \
--set cluster.name=us-west \
--set cluster.id=2 \
--set clustermesh.useAPIServer=true \
--set clustermesh.apiserver.service.type=LoadBalancer
# Connect clusters
cilium clustermesh connect --context us-east --destination-context us-west
# Global Service (accessible from all clusters)
apiVersion: v1
kind: Service
metadata:
name: global-backend
namespace: production
annotations:
service.cilium.io/global: "true"
service.cilium.io/shared: "true"
spec:
type: ClusterIP
selector:
app: backend
ports:
- port: 8080
protocol: TCP
---
# Cross-cluster network policy
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: allow-cross-cluster
namespace: production
spec:
endpointSelector:
matchLabels:
app: frontend
egress:
- toEndpoints:
- matchLabels:
app: backend
io.kubernetes.pod.namespace: production
# Matches pods in ANY connected cluster
toPorts:
- ports:
- port: "8080"
protocol: TCP
Key Points :
cluster.id and cluster.nameProblem : Encrypt all pod-to-pod traffic transparently
# Enable WireGuard encryption
apiVersion: v1
kind: ConfigMap
metadata:
name: cilium-config
namespace: kube-system
data:
enable-wireguard: "true"
enable-wireguard-userspace-fallback: "false"
# Or via Helm
helm upgrade cilium cilium/cilium \
--namespace kube-system \
--reuse-values \
--set encryption.enabled=true \
--set encryption.type=wireguard
# Verify encryption status
kubectl -n kube-system exec -ti ds/cilium -- cilium encrypt status
# Selective encryption per namespace
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: encrypted-namespace
namespace: production
annotations:
cilium.io/encrypt: "true" # Force encryption for this namespace
spec:
endpointSelector: {}
ingress:
- fromEndpoints:
- matchLabels:
io.kubernetes.pod.namespace: production
egress:
- toEndpoints:
- matchLabels:
io.kubernetes.pod.namespace: production
Key Points :
hubble observe --verdict ENCRYPTEDProblem : Debug network connectivity and policy issues
# Install Hubble
helm upgrade cilium cilium/cilium \
--namespace kube-system \
--reuse-values \
--set hubble.relay.enabled=true \
--set hubble.ui.enabled=true
# Port-forward to Hubble UI
cilium hubble ui
# CLI: Watch flows in real-time
hubble observe --namespace production
# Filter by pod
hubble observe --pod production/frontend-7d4c8b6f9-x2m5k
# Show only dropped flows
hubble observe --verdict DROPPED
# Filter by L7 (HTTP)
hubble observe --protocol http --namespace production
# Show flows to specific service
hubble observe --to-service production/backend
# Show flows with DNS queries
hubble observe --protocol dns --verdict FORWARDED
# Export to JSON for analysis
hubble observe --output json > flows.json
# Check policy verdicts
hubble observe --verdict DENIED --namespace production
# Troubleshoot specific connection
hubble observe \
--from-pod production/frontend-7d4c8b6f9-x2m5k \
--to-pod production/backend-5f8d9c4b2-p7k3n \
--verdict DROPPED
Key Points :
--verdict DROPPED reveals policy deniesreferences/observability.mdProblem : Protect Kubernetes nodes from unauthorized access
apiVersion: cilium.io/v2
kind: CiliumClusterwideNetworkPolicy
metadata:
name: host-firewall
spec:
nodeSelector: {} # Apply to all nodes
ingress:
# Allow SSH from bastion hosts only
- fromCIDR:
- 10.0.1.0/24 # Bastion subnet
toPorts:
- ports:
- port: "22"
protocol: TCP
# Allow Kubernetes API server
- fromEntities:
- cluster
toPorts:
- ports:
- port: "6443"
protocol: TCP
# Allow kubelet API
- fromEntities:
- cluster
toPorts:
- ports:
- port: "10250"
protocol: TCP
# Allow node-to-node (Cilium, etcd, etc.)
- fromCIDR:
- 10.0.0.0/16 # Node CIDR
toPorts:
- ports:
- port: "4240" # Cilium health
protocol: TCP
- port: "4244" # Hubble server
protocol: TCP
# Allow monitoring
- fromEndpoints:
- matchLabels:
k8s:io.kubernetes.pod.namespace: monitoring
toPorts:
- ports:
- port: "9090" # Node exporter
protocol: TCP
egress:
# Allow all egress from nodes (can be restricted)
- toEntities:
- all
Key Points :
CiliumClusterwideNetworkPolicy for node-level policieshubble observe --from-reserved:hostPrinciples :
Implementation :
# 1. Default deny all traffic in namespace
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: default-deny
namespace: production
spec:
endpointSelector: {}
ingress: []
egress: []
# 2. Identity-based allow (not CIDR-based)
---
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: allow-by-identity
namespace: production
spec:
endpointSelector:
matchLabels:
app: web
ingress:
- fromEndpoints:
- matchLabels:
app: frontend
env: production # Require specific identity
# 3. Audit mode for testing
---
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: audit-mode-policy
namespace: production
annotations:
cilium.io/policy-audit-mode: "true"
spec:
# Policy logged but not enforced
Multi-Tenancy :
# Isolate tenants by namespace
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: tenant-isolation
namespace: tenant-a
spec:
endpointSelector: {}
ingress:
- fromEndpoints:
- matchLabels:
io.kubernetes.pod.namespace: tenant-a # Same namespace only
egress:
- toEndpoints:
- matchLabels:
io.kubernetes.pod.namespace: tenant-a
- toEntities:
- kube-apiserver
- kube-dns
Environment Isolation (dev/staging/prod):
# Prevent dev from accessing prod
apiVersion: cilium.io/v2
kind: CiliumClusterwideNetworkPolicy
metadata:
name: env-isolation
spec:
endpointSelector:
matchLabels:
env: production
ingress:
- fromEndpoints:
- matchLabels:
env: production # Only prod can talk to prod
ingressDeny:
- fromEndpoints:
- matchLabels:
env: development # Explicit deny from dev
Enable Cilium Service Mesh with mTLS:
helm upgrade cilium cilium/cilium \
--namespace kube-system \
--reuse-values \
--set authentication.mutual.spire.enabled=true \
--set authentication.mutual.spire.install.enabled=true
Enforce mTLS per service:
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: mtls-required
namespace: production
spec:
endpointSelector:
matchLabels:
app: payment-service
ingress:
- fromEndpoints:
- matchLabels:
app: api-gateway
authentication:
mode: "required" # Require mTLS authentication
📚 For comprehensive security patterns :
references/network-policies.md for advanced policy examplesreferences/observability.md for security monitoring with HubbleFollow this test-driven approach for all Cilium implementations:
# Create connectivity test before implementing policy
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
name: connectivity-test-client
namespace: test-ns
labels:
app: test-client
spec:
containers:
- name: curl
image: curlimages/curl:latest
command: ["sleep", "infinity"]
EOF
# Test that should fail after policy is applied
kubectl exec -n test-ns connectivity-test-client -- \
curl -s --connect-timeout 5 http://backend-svc:8080/health
# Expected: Connection should succeed (no policy yet)
# After applying deny policy, this should fail
kubectl exec -n test-ns connectivity-test-client -- \
curl -s --connect-timeout 5 http://backend-svc:8080/health
# Expected: Connection refused/timeout
# Apply the network policy
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: backend-policy
namespace: test-ns
spec:
endpointSelector:
matchLabels:
app: backend
ingress:
- fromEndpoints:
- matchLabels:
app: frontend # Only frontend allowed, not test-client
toPorts:
- ports:
- port: "8080"
protocol: TCP
# Run comprehensive connectivity test
cilium connectivity test --test-namespace=cilium-test
# Verify specific policy enforcement
hubble observe --namespace test-ns --verdict DROPPED \
--from-label app=test-client --to-label app=backend
# Check policy status
cilium policy get -n test-ns
# Validate Cilium agent health
kubectl -n kube-system exec ds/cilium -- cilium status
# Verify all endpoints have identity
cilium endpoint list
# Check BPF policy map
kubectl -n kube-system exec ds/cilium -- cilium bpf policy get --all
# Validate no unexpected drops
hubble observe --verdict DROPPED --last 100 | grep -v "expected"
# Helm test for installation validation
helm test cilium -n kube-system
# Test Cilium installation integrity
helm test cilium --namespace kube-system --logs
# Validate values before upgrade
helm template cilium cilium/cilium \
--namespace kube-system \
--values values.yaml \
--validate
# Dry-run upgrade
helm upgrade cilium cilium/cilium \
--namespace kube-system \
--values values.yaml \
--dry-run
Bad - Complex selectors cause slow policy evaluation:
# BAD: Multiple label matches with regex-like behavior
spec:
endpointSelector:
matchExpressions:
- key: app
operator: In
values: [frontend-v1, frontend-v2, frontend-v3, frontend-v4]
- key: version
operator: NotIn
values: [deprecated, legacy]
Good - Simplified selectors with efficient matching:
# GOOD: Single label with aggregated selector
spec:
endpointSelector:
matchLabels:
app: frontend
tier: web # Use aggregated label instead of version list
Bad - Policies that don't cache well:
# BAD: CIDR-based rules require per-packet evaluation
egress:
- toCIDR:
- 10.0.0.0/8
- 172.16.0.0/12
- 192.168.0.0/16
Good - Identity-based rules with eBPF map caching:
# GOOD: Identity-based selectors use efficient BPF map lookups
egress:
- toEndpoints:
- matchLabels:
app: backend
io.kubernetes.pod.namespace: production
- toEntities:
- cluster # Pre-cached entity
Bad - All DNS queries go to cluster DNS:
# BAD: Cross-node DNS queries add latency
# Default CoreDNS deployment
Good - Enable node-local DNS cache:
# GOOD: Enable node-local DNS in Cilium
helm upgrade cilium cilium/cilium \
--namespace kube-system \
--reuse-values \
--set nodeLocalDNS.enabled=true
# Or use Cilium's DNS proxy with caching
--set dnsproxy.enableDNSCompression=true \
--set dnsproxy.endpointMaxIpPerHostname=50
Bad - Full flow capture in production:
# BAD: 100% sampling causes high CPU/memory usage
hubble:
metrics:
enabled: true
relay:
enabled: true
# Default: all flows captured
Good - Sampling for production workloads:
# GOOD: Sample flows in production
hubble:
metrics:
enabled: true
serviceMonitor:
enabled: true
relay:
enabled: true
prometheus:
enabled: true
# Reduce cardinality
redact:
enabled: true
httpURLQuery: true
httpHeaders:
allow:
- "Content-Type"
# Use selective flow export
hubble:
export:
static:
enabled: true
filePath: /var/run/cilium/hubble/events.log
fieldMask:
- time
- verdict
- drop_reason
- source.namespace
- destination.namespace
Bad - L7 policies on all traffic:
# BAD: L7 parsing on all pods causes high overhead
spec:
endpointSelector: {} # All pods
ingress:
- toPorts:
- ports:
- port: "8080"
rules:
http:
- method: ".*"
Good - Selective L7 policy for specific services:
# GOOD: L7 only on services that need it
spec:
endpointSelector:
matchLabels:
app: api-gateway # Only on gateway
requires-l7: "true"
ingress:
- fromEndpoints:
- matchLabels:
app: frontend
toPorts:
- ports:
- port: "8080"
rules:
http:
- method: "GET|POST"
path: "/api/v1/.*"
Bad - Default CT table sizes for large clusters:
# BAD: Default may be too small for high-connection workloads
# Can cause connection failures
Good - Tune CT limits based on workload:
# GOOD: Adjust for cluster size
helm upgrade cilium cilium/cilium \
--namespace kube-system \
--reuse-values \
--set bpf.ctTcpMax=524288 \
--set bpf.ctAnyMax=262144 \
--set bpf.natMax=524288 \
--set bpf.policyMapMax=65536
#!/bin/bash
# test-network-policies.sh
set -e
NAMESPACE="policy-test"
# Setup test namespace
kubectl create namespace $NAMESPACE --dry-run=client -o yaml | kubectl apply -f -
# Deploy test pods
kubectl apply -f - <<EOF
apiVersion: v1
kind: Pod
metadata:
name: client
namespace: $NAMESPACE
labels:
app: client
spec:
containers:
- name: curl
image: curlimages/curl:latest
command: ["sleep", "infinity"]
---
apiVersion: v1
kind: Pod
metadata:
name: server
namespace: $NAMESPACE
labels:
app: server
spec:
containers:
- name: nginx
image: nginx:alpine
ports:
- containerPort: 80
EOF
# Wait for pods
kubectl wait --for=condition=Ready pod/client pod/server -n $NAMESPACE --timeout=60s
# Test 1: Baseline connectivity (should pass)
echo "Test 1: Baseline connectivity..."
SERVER_IP=$(kubectl get pod server -n $NAMESPACE -o jsonpath='{.status.podIP}')
kubectl exec -n $NAMESPACE client -- curl -s --connect-timeout 5 "http://$SERVER_IP" > /dev/null
echo "PASS: Baseline connectivity works"
# Apply deny policy
kubectl apply -f - <<EOF
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: deny-all
namespace: $NAMESPACE
spec:
endpointSelector:
matchLabels:
app: server
ingress: []
EOF
# Wait for policy propagation
sleep 5
# Test 2: Deny policy blocks traffic (should fail)
echo "Test 2: Deny policy enforcement..."
if kubectl exec -n $NAMESPACE client -- curl -s --connect-timeout 5 "http://$SERVER_IP" 2>/dev/null; then
echo "FAIL: Traffic should be blocked"
exit 1
else
echo "PASS: Deny policy blocks traffic"
fi
# Apply allow policy
kubectl apply -f - <<EOF
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: allow-client
namespace: $NAMESPACE
spec:
endpointSelector:
matchLabels:
app: server
ingress:
- fromEndpoints:
- matchLabels:
app: client
toPorts:
- ports:
- port: "80"
protocol: TCP
EOF
sleep 5
# Test 3: Allow policy permits traffic (should pass)
echo "Test 3: Allow policy enforcement..."
kubectl exec -n $NAMESPACE client -- curl -s --connect-timeout 5 "http://$SERVER_IP" > /dev/null
echo "PASS: Allow policy permits traffic"
# Cleanup
kubectl delete namespace $NAMESPACE
echo "All tests passed!"
#!/bin/bash
# test-hubble-flows.sh
# Verify Hubble is capturing flows
echo "Checking Hubble flow capture..."
# Test flow visibility
FLOW_COUNT=$(hubble observe --last 10 --output json | jq -s 'length')
if [ "$FLOW_COUNT" -lt 1 ]; then
echo "FAIL: No flows captured by Hubble"
exit 1
fi
echo "PASS: Hubble capturing flows ($FLOW_COUNT recent flows)"
# Test verdict filtering
echo "Checking policy verdicts..."
hubble observe --verdict FORWARDED --last 5 --output json | jq -e '.' > /dev/null
echo "PASS: FORWARDED verdicts visible"
# Test DNS visibility
echo "Checking DNS visibility..."
hubble observe --protocol dns --last 5 --output json | jq -e '.' > /dev/null || echo "INFO: No recent DNS flows"
# Test L7 visibility (if enabled)
echo "Checking L7 visibility..."
hubble observe --protocol http --last 5 --output json | jq -e '.' > /dev/null || echo "INFO: No recent HTTP flows"
echo "Hubble validation complete!"
#!/bin/bash
# test-cilium-health.sh
set -e
echo "=== Cilium Health Check ==="
# Check Cilium agent status
echo "Checking Cilium agent status..."
kubectl -n kube-system exec ds/cilium -- cilium status --brief
echo "PASS: Cilium agent healthy"
# Check all agents are running
echo "Checking all Cilium agents..."
DESIRED=$(kubectl get ds cilium -n kube-system -o jsonpath='{.status.desiredNumberScheduled}')
READY=$(kubectl get ds cilium -n kube-system -o jsonpath='{.status.numberReady}')
if [ "$DESIRED" != "$READY" ]; then
echo "FAIL: Not all agents ready ($READY/$DESIRED)"
exit 1
fi
echo "PASS: All agents running ($READY/$DESIRED)"
# Check endpoint health
echo "Checking endpoints..."
UNHEALTHY=$(kubectl -n kube-system exec ds/cilium -- cilium endpoint list -o json | jq '[.[] | select(.status.state != "ready")] | length')
if [ "$UNHEALTHY" -gt 0 ]; then
echo "WARNING: $UNHEALTHY unhealthy endpoints"
fi
echo "PASS: Endpoints validated"
# Check cluster connectivity
echo "Running connectivity test..."
cilium connectivity test --test-namespace=cilium-test --single-node
echo "PASS: Connectivity test passed"
echo "=== All health checks passed ==="
❌ WRONG : Assume cluster is secure without policies
# No network policies = all traffic allowed!
# Attackers can move laterally freely
✅ CORRECT : Implement default-deny per namespace
apiVersion: cilium.io/v2
kind: CiliumNetworkPolicy
metadata:
name: default-deny
namespace: production
spec:
endpointSelector: {}
ingress: []
egress: []
❌ WRONG : Block all egress without allowing DNS
# Pods can't resolve DNS names!
egress: []
✅ CORRECT : Always allow DNS
egress:
- toEndpoints:
- matchLabels:
io.kubernetes.pod.namespace: kube-system
k8s-app: kube-dns
toPorts:
- ports:
- port: "53"
protocol: UDP
❌ WRONG : Hard-code pod IPs (IPs change!)
egress:
- toCIDR:
- 10.0.1.42/32 # Pod IP - will break when pod restarts
✅ CORRECT : Use identity-based selectors
egress:
- toEndpoints:
- matchLabels:
app: backend
version: v2
❌ WRONG : Deploy enforcing policies directly to production
# No audit mode - might break production traffic
spec:
endpointSelector: {...}
ingress: [...]
✅ CORRECT : Test with audit mode first
metadata:
annotations:
cilium.io/policy-audit-mode: "true"
spec:
endpointSelector: {...}
ingress: [...]
# Review Hubble logs for AUDIT verdicts
# Remove annotation when ready to enforce
❌ WRONG : Allow entire TLDs
toFQDNs:
- matchPattern: "*.com" # Allows ANY .com domain!
✅ CORRECT : Be specific with domains
toFQDNs:
- matchName: "api.stripe.com"
- matchPattern: "*.stripe.com" # Only Stripe subdomains
❌ WRONG : Deploy Cilium without observability
# Can't see why traffic is being dropped!
# Blind troubleshooting with kubectl logs
✅ CORRECT : Always enable Hubble
helm upgrade cilium cilium/cilium \
--set hubble.relay.enabled=true \
--set hubble.ui.enabled=true
# Troubleshoot with visibility
hubble observe --verdict DROPPED
❌ WRONG : Set policies and forget
✅ CORRECT : Continuous monitoring
# Alert on policy denies
hubble observe --verdict DENIED --output json \
| jq -r '.flow | "\(.time) \(.source.namespace)/\(.source.pod_name) -> \(.destination.namespace)/\(.destination.pod_name) DENIED"'
# Export metrics to Prometheus
# Alert on spike in dropped flows
❌ WRONG : No resource limits on Cilium agents
# Can cause OOM kills, crashes
✅ CORRECT : Set appropriate limits
resources:
limits:
memory: 4Gi # Adjust based on cluster size
cpu: 2
requests:
memory: 2Gi
cpu: 500m
cilium version for feature compatibilitycilium status and cilium connectivity testcilium.io/policy-audit-mode: "true"toEntities: [kube-apiserver]kubectl get pods -l app=backend to testcilium connectivity testhubble observe --verdict DROPPEDhelm template --validate for chart changescilium status shows feature availabilitykubectl -n kube-system get pods -l k8s-app=ciliumYou are a Cilium expert who:
Key Principles :
References :
references/network-policies.md - Comprehensive L3/L4/L7 policy examplesreferences/observability.md - Hubble setup, troubleshooting workflows, metricsTarget Users : Platform engineers, SRE teams, network engineers building secure, high-performance Kubernetes platforms.
Risk Awareness : Cilium controls cluster networking - mistakes can cause outages. Always test changes in non-production environments first.
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