在我之前的文章 K8S 生态周报| Google 选择 Cilium 作为 GKE 下一代数据面[1] 一文中，我介绍了 Google 宣布使用 Cilium 作为 GKE 的下一代数据面，及其背后的故事。
Google 选择 Cilium 主要是为了增加 GKE 平台的容器安全性和可观测性。那么，Cilium 到底是什么，为什么会有这么强的吸引力呢？
摘一段官网的介绍：
“Cilium is open source software for transparently securing the network connectivity between application services deployed using Linux container management platforms like Docker and Kubernetes.
”Cilium 是一个用于透明保护部署在 Linux 容器管理平台（比如 Docker 和 Kubernetes）上的应用服务之间网络连接的开源软件。
为什么着重强调是 “Linux 容器管理平台” 呢？这就不得不提到 Cilium 的实现了。Cilium 的基础是一种称为 eBPF 的 Linux 内核技术，使用 eBPF 可以在 Linux 自身内部动态的插入一些控制逻辑，从而满足可观察性和安全性相关的需求。
只谈概念毕竟过于空洞，本节我们直接上手实践一下 Cilium 。
这里我使用 KIND[2] 来创建一套多节点的本地集群。
在创建集群时候，通过配置文件来禁用掉 KIND 默认的 CNI 插件。
kind: Cluster apiVersion: kind.x-k8s.io/v1alpha4 nodes: - role: control-plane - role: worker - role: worker - role: worker networking: disableDefaultCNI: true将配置文件命名为 kindconfig ，通过 --config 参数来指定它。通过 --image 参数可指定创建集群所使用的镜像，这里我使用 kindest/node:v1.19.0@sha256:6a6e4d588db3c2873652f382465eeadc2644562a64659a1da4 来创建一个最新的 Kubernetes v1.19.0 版本的集群。
(MoeLove) ➜ ~ kind create cluster --config=kindconfig --image=kindest/node:v1.19.0@sha256:6a6e4d588db3c2873652f382465eeadc2644562a64659a1da4 db73d3beaa8848 Creating cluster "kind" ... ✓ Ensuring node image (kindest/node:v1.19.0) ???? ✓ Preparing nodes ???? ???? ???? ???? ✓ Writing configuration ???? ✓ Starting control-plane ????️ ✓ Installing StorageClass ???? ✓ Joining worker nodes ???? Set kubectl context to "kind-kind" You can now use your cluster with: kubectl cluster-info --context kind-kind Have a question, bug, or feature request? Let us know! https://kind.sigs.k8s.io/#community ????由于我们已经禁用了 KIND 默认的 CNI ，所以现在集群的 Node 都是 NotReady 的状态，等待 CNI 的初始化。
(MoeLove) ➜ ~ kubectl get nodes NAME STATUS ROLES AGE VERSION kind-control-plane NotReady master 85s v1.19.0 kind-worker NotReady <none> 49s v1.19.0 kind-worker2 NotReady <none> 49s v1.19.0 kind-worker3 NotReady <none> 49s v1.19.0部署 Cilium 可以有多种方式，这里我们选择最简单的，直接使用 Helm 3 进行部署。
Cilium 提供了官方维护的 Helm 仓库，我们先来添加它。
注意：请使用 Helm 3。在之前的文章 K8S 生态周报| Helm v2 进入维护期倒计时[3] 中，我曾介绍过 Helm v2 的维护期已经进入倒计时，三个月后将停止为 Helm v2 提供安全补丁，届时 Helm v2 的维护期就彻底终止了。
(MoeLove) ➜ ~ helm repo add cilium https://helm.cilium.io/ "cilium" has been added to your repositories这一步并非必须。只是由于每个在 Node 上都需要下载 cilium/cilium:v1.8.2 的镜像，会很耗时，所以我们可以直接使用 kind load docker-image 将主机 Docker 中的镜像加载到 KIND 创建的集群中。
# 下载镜像 (MoeLove) ➜ ~ docker pull cilium/cilium:v1.8.2 v1.8.2: Pulling from cilium/cilium Digest: sha256:9dffe79408025f7523a94a1828ac1691b997a2b1dbd69af338cfbecc8428d326 Status: Image is up to date for cilium/cilium:v1.8.2 docker.io/cilium/cilium:v1.8.2 # 将镜像加载到 KIND 集群中 (MoeLove) ➜ ~ kind load docker-image cilium/cilium:v1.8.2 Image: "cilium/cilium:v1.8.2" with ID "sha256:009715be68951ab107617f04dc50bcceb3d3f1e0c09db156aacf95e56eb0d5cc" not yet present on node "kind-worker3", loading... Image: "cilium/cilium:v1.8.2" with ID "sha256:009715be68951ab107617f04dc50bcceb3d3f1e0c09db156aacf95e56eb0d5cc" not yet present on node "kind-control-plane", loading... Image: "cilium/cilium:v1.8.2" with ID "sha256:009715be68951ab107617f04dc50bcceb3d3f1e0c09db156aacf95e56eb0d5cc" not yet present on node "kind-worker", loading... Image: "cilium/cilium:v1.8.2" with ID "sha256:009715be68951ab107617f04dc50bcceb3d3f1e0c09db156aacf95e56eb0d5cc" not yet present on node "kind-worker2", loading...镜像加载完成后，可使用如下命令进行二次确认：
for i in `docker ps --filter label=io.x-k8s.kind.cluster=kind -q` do docker exec $i ctr -n k8s.io -a /run/containerd/containerd.sock i ls |grep cilium done这里对几个配置项做下说明：
global.hubble.enabled=true ：表示启用 Hubble 。
global.hubble.metrics.enabled="{dns,drop,tcp,flow,port-distribution,icmp,http}：表示 Hubble 暴露出的 metrics 中包含哪些内容，如果不指定则表示禁用它。
global.hubble.ui.enabled=true ：表示启用 Hubble UI
对于 Hubble 是什么，我们稍后再介绍。
当 Cilium 部署完成后，我们可以查看下部署的 ns 下的 Pod 情况：
(MoeLove) ➜ ~ kubectl -n kube-system get pods NAME READY STATUS RESTARTS AGE cilium-86dbc 1/1 Running 0 2m11s cilium-cjcps 1/1 Running 0 2m11s cilium-f8dtm 1/1 Running 0 2m11s cilium-node-init-9r9cm 1/1 Running 1 2m11s cilium-node-init-bkg28 1/1 Running 1 2m11s cilium-node-init-jgx6r 1/1 Running 1 2m11s cilium-node-init-s7xhx 1/1 Running 1 2m11s cilium-operator-756cc96896-brlrh 1/1 Running 0 2m11s cilium-t8kqc 1/1 Running 0 2m11s coredns-f9fd979d6-7vfnq 1/1 Running 0 6m16s coredns-f9fd979d6-h7rfw 1/1 Running 0 6m16s etcd-kind-control-plane 1/1 Running 0 6m19s hubble-relay-666ddfd69b-2lpsz 1/1 Running 0 2m11s hubble-ui-7854cf65dc-ncj89 1/1 Running 0 2m11s kube-apiserver-kind-control-plane 1/1 Running 0 6m19s kube-controller-manager-kind-control-plane 1/1 Running 0 6m19s kube-proxy-48rwk 1/1 Running 0 6m16s kube-proxy-8mn58 1/1 Running 0 5m59s kube-proxy-jptln 1/1 Running 0 5m59s kube-proxy-pp24h 1/1 Running 0 5m59s kube-scheduler-kind-control-plane 1/1 Running 0 6m19s查看 Node 的状态：
(MoeLove) ➜ ~ kubectl get nodes NAME STATUS ROLES AGE VERSION kind-control-plane Ready master 7m1s v1.19.0 kind-worker Ready <none> 6m26s v1.19.0 kind-worker2 Ready <none> 6m26s v1.19.0 kind-worker3 Ready <none> 6m26s v1.19.0上文中，通过 Helm 部署 Cilium 时，我们指定了一些与 Hubble 有关的参数，但尚未介绍 Hubble 具体是什么。这里简单介绍下。
Hubble 是一个完全分布式的网络和安全性的可观察性平台，它建立在 Cilium 和 eBPF 之上，以完全透明的方式深入了解服务以及网络基础结构的通信和行为。
由于它是构建在 Cilium 之上的，Hubble 可以利用 eBPF 获得可见性。通过使用 eBPF ，所有可见性都是可编程的，并且可以最大程度的减少开销，同时根据用户需要提供深入和详尽的可见性。例如：
了解服务之间的依赖关系。可以观测到服务之间是否有通信，通信频率，以及 HTTP 调用产生的状态码等；
监控网络和告警。可以观测到网络连接是否异常，是 L4 还是 L7 有问题，DNS 查询是否异常等；
监控应用程序。可以观测到 HTTP 4xx/5xx 的错误率，HTTP 请求和响应的 95 值，99值等；
监控安全问题。可以观测到哪些请求是被 Network Policy 所拒绝的，哪些服务解析了特定的域名等；
我们可以直接使用 hubble observe 观测当前集群中的连接情况：
(MoeLove) ➜ hubble-ui git:(master) kubectl exec -n kube-system -t ds/cilium -- hubble observe TIMESTAMP SOURCE DESTINATION TYPE VERDICT SUMMARY Sep 2 07:06:41.624 kube-system/coredns-f9fd979d6-h7rfw:8181 10.244.1.50:52404 to-stack FORWARDED TCP Flags: ACK, FIN Sep 2 07:06:41.625 10.244.1.50:52404 kube-system/coredns-f9fd979d6-h7rfw:8181 to-endpoint FORWARDED TCP Flags: ACK, FIN Sep 2 07:06:42.376 10.244.1.12:4240 10.244.0.76:45164 to-overlay FORWARDED TCP Flags: ACK Sep 2 07:06:42.376 10.244.0.76:45164 10.244.1.12:4240 to-endpoint FORWARDED TCP Flags: ACK Sep 2 07:06:42.778 10.244.1.50:37512 10.244.1.12:4240 to-endpoint FORWARDED TCP Flags: ACK, PSH Sep 2 07:06:42.778 10.244.1.12:4240 10.244.1.50:37512 to-stack FORWARDED TCP Flags: ACK, PSH Sep 2 07:06:44.941 10.244.1.50:59870 10.244.0.108:4240 to-overlay FORWARDED TCP Flags: ACK Sep 2 07:06:44.941 10.244.1.12:4240 10.244.2.220:47616 to-overlay FORWARDED TCP Fla gs: ACK Sep 2 07:06:44.941 10.244.1.50:52090 10.244.3.159:4240 to-overlay FORWARDED TCP Fla gs: ACK Sep 2 07:06:44.941 10.244.1.50:52958 10.244.2.81:4240 to-overlay FORWARDED TCP Fla gs: ACK Sep 2 07:06:44.941 10.244.2.220:47616 10.244.1.12:4240 to-endpoint FORWARDED TCP Fla gs: ACK Sep 2 07:06:45.448 10.244.1.12:4240 10.244.3.111:54012 to-overlay FORWARDED TCP Fla gs: ACK Sep 2 07:06:45.449 10.244.3.111:54012 10.244.1.12:4240 to-endpoint FORWARDED TCP Fla gs: ACK Sep 2 07:06:47.631 kube-system/coredns-f9fd979d6-h7rfw:36120 172.18.0.4:6443 to-stack FORWARDED TCP Fla gs: ACK Sep 2 07:06:47.822 10.244.1.50:60914 kube-system/coredns-f9fd979d6-h7rfw:8080 to-endpoint FORWARDED TCP Fla gs: SYN Sep 2 07:06:47.822 kube-system/coredns-f9fd979d6-h7rfw:8080 10.244.1.50:60914 to-stack FORWARDED TCP Fla gs: SYN, ACK Sep 2 07:06:47.822 10.244.1.50:60914 kube-system/coredns-f9fd979d6-h7rfw:8080 to-endpoint FORWARDED TCP Fla gs: ACK Sep 2 07:06:47.823 kube-system/coredns-f9fd979d6-h7rfw:8080 10.244.1.50:60914 to-stack FORWARDED TCP Fla gs: ACK, PSH Sep 2 07:06:47.823 kube-system/coredns-f9fd979d6-h7rfw:8080 10.244.1.50:60914 to-stack FORWARDED TCP Fla gs: ACK, FIN Sep 2 07:06:47.823 10.244.1.50:60914 kube-system/coredns-f9fd979d6-h7rfw:8080 to-endpoint FORWARDED TCP Fla gs: ACK, PSH可以看到内容很详细，包括通信的两端，以及发的包是 ACK 还是 SYN 等信息均可观测到。
这里我们部署一个测试应用来实际体验下 Cilium 提供的强大功能。官方仓库中提供了一个 connectivity-check[4] 的测试用例，这里我对它做了精简和修改，以便理解。
这里定义的内容如下：
1 个名为 echo-a 的 svc ，用于暴露 echo-a 这个测试服务；
4 个 deploy ，分别是 1 个测试服务，以及三个用于测试与 echo-a 联通性的 deploy;
2 个 CiliumNetworkPolicy，用来控制是否允许与 echo-a 联通；
--- apiVersion: v1 kind: Service metadata: name: echo-a spec: type: ClusterIP ports: - port: 80 selector: name: echo-a --- apiVersion: apps/v1 kind: Deployment metadata: name: echo-a spec: selector: matchLabels: name: echo-a replicas: 1 template: metadata: labels: name: echo-a spec: containers: - name: echo-container image: docker.io/cilium/json-mock:1.0 imagePullPolicy: IfNotPresent readinessProbe: exec: command: ["curl", "-sS", "--fail", "-o", "/dev/null", "localhost"] --- apiVersion: apps/v1 kind: Deployment metadata: name: pod-to-a-allowed-cnp spec: selector: matchLabels: name: pod-to-a-allowed-cnp replicas: 1 template: metadata: labels: name: pod-to-a-allowed-cnp spec: containers: - name: pod-to-a-allowed-cnp-container image: docker.io/byrnedo/alpine-curl:0.1.8 command: ["/bin/ash", "-c", "sleep 1000000000"] imagePullPolicy: IfNotPresent livenessProbe: exec: command: ["curl", "-sS", "--fail", "-o", "/dev/null", "echo-a"] readinessProbe: exec: command: ["curl", "-sS", "--fail", "-o", "/dev/null", "echo-a"] --- apiVersion: "cilium.io/v2" kind: CiliumNetworkPolicy metadata: name: "pod-to-a-allowed-cnp" spec: endpointSelector: matchLabels: name: pod-to-a-allowed-cnp egress: - toEndpoints: - matchLabels: name: echo-a toPorts: - ports: - port: "80" protocol: TCP - toEndpoints: - matchLabels: k8s:io.kubernetes.pod.namespace: kube-system k8s:k8s-app: kube-dns toPorts: - ports: - port: "53" protocol: UDP --- apiVersion: apps/v1 kind: Deployment metadata: name: pod-to-a-l3-denied-cnp spec: selector: matchLabels: name: pod-to-a-l3-denied-cnp replicas: 1 template: metadata: labels: name: pod-to-a-l3-denied-cnp spec: containers: - name: pod-to-a-l3-denied-cnp-container image: docker.io/byrnedo/alpine-curl:0.1.8 command: ["/bin/ash", "-c", "sleep 1000000000"] imagePullPolicy: IfNotPresent livenessProbe: timeoutSeconds: 7 exec: command: ["ash", "-c", "! curl -sS --fail --connect-timeout 5 -o /dev/null echo-a"] readinessProbe: timeoutSeconds: 7 exec: command: ["ash", "-c", "! curl -sS --fail --connect-timeout 5 -o /dev/null echo-a"] --- apiVersion: "cilium.io/v2" kind: CiliumNetworkPolicy metadata: name: "pod-to-a-l3-denied-cnp" spec: endpointSelector: matchLabels: name: pod-to-a-l3-denied-cnp egress: - toEndpoints: - matchLabels: k8s:io.kubernetes.pod.namespace: kube-system k8s:k8s-app: kube-dns toPorts: - ports: - port: "53" protocol: UDP --- apiVersion: apps/v1 kind: Deployment metadata: name: pod-to-a spec: selector: matchLabels: name: pod-to-a replicas: 1 template: metadata: labels: name: pod-to-a spec: containers: - name: pod-to-a-container image: docker.io/byrnedo/alpine-curl:0.1.8 command: ["/bin/ash", "-c", "sleep 1000000000"] imagePullPolicy: IfNotPresent livenessProbe: exec: command: ["curl", "-sS", "--fail", "-o", "/dev/null", "echo-a"]直接部署即可：
(MoeLove) ➜ ~ kubectl apply -f cilium-demo.yaml service/echo-a created deployment.apps/echo-a created deployment.apps/pod-to-a-allowed-cnp created ciliumnetworkpolicy.cilium.io/pod-to-a-allowed-cnp created deployment.apps/pod-to-a-l3-denied-cnp created ciliumnetworkpolicy.cilium.io/pod-to-a-l3-denied-cnp created deployment.apps/pod-to-a created查看 Pod 状态，看看状态是否正常：
(MoeLove) ➜ ~ kubectl get pods NAME READY STATUS RESTARTS AGE echo-a-8b6595b89-w9kt2 1/1 Running 0 49s pod-to-a-5567c85856-xsg5b 1/1 Running 0 49s pod-to-a-allowed-cnp-7b85c8db8-jrjhx 1/1 Running 0 49s pod-to-a-l3-denied-cnp-7f64d7b7c4-fsxrm 1/1 Running 0 49s接下来，使用 hubble observe 观察下效果，已经可以看到我们部署的应用产生的连接了。
(MoeLove) ➜ ~ kubectl exec -n kube-system -t ds/cilium -- hubble observe TIMESTAMP SOURCE DESTINATION TYPE VERDICT SUMMARY Sep 3 00:00:13.481 default/pod-to-a-5567c85856-xsg5b:60784 default/echo-a-8b6595b89-w9kt2:80 to-endpoint FORWARDED TCP Flags: ACK, PSH Sep 3 00:00:15.429 kube-system/coredns-f9fd979d6-h7rfw:53 default/pod-to-a-allowed-cnp-7b85c8db8-jrjhx:43696 to-endpoint FORWARDED UDP Sep 3 00:00:16.010 10.244.1.12:4240 10.244.2.220:50830 to-overlay FORWARDED TCP Flags: ACK Sep 3 00:00:16.010 10.244.1.12:4240 10.244.1.50:40402 to-stack FORWARDED TCP Flags: ACK Sep 3 00:00:16.010 10.244.1.50:40402 10.244.1.12:4240 to-endpoint FORWARDED TCP Flags: ACK Sep 3 00:00:16.011 10.244.2.220:50830 10.244.1.12:4240 to-endpoint FORWARDED TCP Flags: ACK Sep 3 00:00:16.523 10.244.1.12:4240 10.244.3.111:57242 to-overlay FORWARDED TCP Flags: ACK Sep 3 00:00:16.523 10.244.3.111:57242 10.244.1.12:4240 to-endpoint FORWARDED TCP Flags: ACK Sep 3 00:00:21.376 kube-system/coredns-f9fd979d6-h7rfw:53 default/pod-to-a-l3-denied-cnp-7f64d7b7c4-fsxrm:44785 to-overlay FORWARDED UDP Sep 3 00:00:21.377 kube-system/coredns-f9fd979d6-h7rfw:53 default/pod-to-a-l3-denied-cnp-7f64d7b7c4-fsxrm:44785 to-overlay FORWARDED UDP Sep 3 00:00:23.896 kube-system/coredns-f9fd979d6-h7rfw:36120 172.18.0.4:6443 to-stack FORWARDED TCP Flags: ACK Sep 3 00:00:25.428 default/pod-to-a-allowed-cnp-7b85c8db8-jrjhx:55678 default/echo-a-8b6595b89-w9kt2:80 L3-L4 FORWARDED TCP Flags: SYN Sep 3 00:00:25.428 default/pod-to-a-allowed-cnp-7b85c8db8-jrjhx:55678 default/echo-a-8b6595b89-w9kt2:80 to-endpoint FORWARDED TCP Flags: SYN Sep 3 00:00:25.428 default/echo-a-8b6595b89-w9kt2:80 default/pod-to-a-allowed-cnp-7b85c8db8-jrjhx:55678 to-endpoint FORWARDED TCP Flags: SYN, ACK Sep 3 00:00:25.428 default/pod-to-a-allowed-cnp-7b85c8db8-jrjhx:55678 default/echo-a-8b6595b89-w9kt2:80 to-endpoint FORWARDED TCP Flags: ACK Sep 3 00:00:25.428 default/pod-to-a-allowed-cnp-7b85c8db8-jrjhx:55678 default/echo-a-8b6595b89-w9kt2:80 to-endpoint FORWARDED TCP Flags: ACK, PSH Sep 3 00:00:25.429 default/pod-to-a-allowed-cnp-7b85c8db8-jrjhx:55678 default/echo-a-8b6595b89-w9kt2:80 to-endpoint FORWARDED TCP Flags: ACK, FIN Sep 3 00:00:29.546 10.244.1.50:57770 kube-system/coredns-f9fd979d6-h7rfw:8080 to-endpoint FORWARDED TCP Flags: SYN Sep 3 00:00:29.546 kube-system/coredns-f9fd979d6-h7rfw:8080 10.244.1.50:57770 to-stack FORWARDED TCP Flags: SYN, ACK Sep 3 00:00:29.546 10.244.1.50:57770 kube-system/coredns-f9fd979d6-h7rfw:8080 to-endpoint FORWARDED TCP Flags: ACK还记得我们在上文中部署 Cilium 时候配置的几个关于 Hubble 的参数么，现在我们可以使用 Hubble UI 来看看效果。
先检查下 kube-system ns 下，是否有 hubble-ui 这个 svc 。
(MoeLove) ➜ kubectl -n kube-system get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE hubble-metrics ClusterIP None <none> 9091/TCP 4m31s hubble-relay ClusterIP 10.102.90.19 <none> 80/TCP 4m31s hubble-ui ClusterIP 10.96.69.234 <none> 80/TCP 4m31s kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP,9153/TCP 8m51s直接使用 kubectl port-forward ，从本地来访问 Hubble UI 。
(MoeLove) ➜ ~ kubectl -n kube-system port-forward svc/hubble-ui 12000:80 Forwarding from 127.0.0.1:12000 -> 12000 Forwarding from [::1]:12000 -> 12000浏览器中打开 http://127.0.0.1:12000 即可。
Hubble UI - https:/moelove.info可以看到我们刚才部署的所有 Pod，以及查看到相应的 CiliumNetworkPolicy 等信息，这里就不赘述了，有兴趣的小伙伴可以自行探索下。
我们也可以使用 Hubble 暴露出来的 metrics 进行观测：
(MoeLove) ➜ ~ kubectl port-forward -n kube-system ds/cilium 19091:9091 Forwarding from 127.0.0.1:19091 -> 9091 Forwarding from [::1]:19091 -> 9091简单看下其中的内容，包含各类请求/响应/丢弃等相关的统计信息，还有包括每个目标端口包的数量统计等。感兴趣的小伙伴可以自行探索下。
(MoeLove) ➜ ~ curl -s localhost:19091/metrics | head -n 22 # HELP hubble_dns_queries_total Number of DNS queries observed # TYPE hubble_dns_queries_total counter hubble_dns_queries_total{ips_returned="0",qtypes="A",rcode=""} 1165 hubble_dns_queries_total{ips_returned="0",qtypes="AAAA",rcode=""} 1165 # HELP hubble_dns_response_types_total Number of DNS queries observed # TYPE hubble_dns_response_types_total counter hubble_dns_response_types_total{qtypes="A",type="A"} 233 hubble_dns_response_types_total{qtypes="AAAA",type="AAAA"} 233 # HELP hubble_dns_responses_total Number of DNS queries observed # TYPE hubble_dns_responses_total counter hubble_dns_responses_total{ips_returned="0",qtypes="A",rcode="Non-Existent Domain"} 932 hubble_dns_responses_total{ips_returned="0",qtypes="AAAA",rcode="Non-Existent Domain"} 932 hubble_dns_responses_total{ips_returned="1",qtypes="A",rcode="No Error"} 233 hubble_dns_responses_total{ips_returned="1",qtypes="AAAA",rcode="No Error"} 233 # HELP hubble_drop_total Number of drops # TYPE hubble_drop_total counter hubble_drop_total{protocol="ICMPv4",reason="Policy denied"} 459 hubble_drop_total{protocol="ICMPv4",reason="Unsupported protocol for NAT masquerade"} 731 hubble_drop_total{protocol="ICMPv6",reason="Unsupported L3 protocol"} 213 hubble_drop_total{protocol="TCP",reason="Policy denied"} 1425 hubble_drop_total{protocol="UDP",reason="Stale or unroutable IP"} 6 hubble_drop_total{protocol="Unknown flow",reason="Policy denied"} 1884说了这么多，我们来验证下刚才部署的 CiliumNetworkPolicy 的实际效果吧。
以下是刚才部署的测试 Pod， 我们通过这些 Pod 来访问 echo-a 这个 svc 。
(MoeLove) ➜ ~ kubectl get pods NAME READY STATUS RESTARTS AGE echo-a-8b6595b89-w9kt2 1/1 Running 0 79m pod-to-a-5567c85856-xsg5b 1/1 Running 0 79m pod-to-a-allowed-cnp-7b85c8db8-jrjhx 1/1 Running 0 79m pod-to-a-l3-denied-cnp-7f64d7b7c4-fsxrm 1/1 Running 0 79mpod-to-a 这是未配置任何 CiliumNetworkPolicy 规则的 Pod
(MoeLove) ➜ ~ kubectl exec pod-to-a-5567c85856-xsg5b -- curl -sI --connect-timeout 5 echo-a HTTP/1.1 200 OK X-Powered-By: Express Vary: Origin, Accept-Encoding Access-Control-Allow-Credentials: true Accept-Ranges: bytes Cache-Control: public, max-age=0 Last-Modified: Sat, 26 Oct 1985 08:15:00 GMT ETag: W/"83d-7438674ba0" Content-Type: text/html; charset=UTF-8 Content-Length: 2109 Date: Thu, 03 Sep 2020 00:54:05 GMT Connection: keep-alivepod-to-a-allowed-cnp 配置了允许通过 TCP 访问 echo-a
(MoeLove) ➜ ~ kubectl exec pod-to-a-allowed-cnp-7b85c8db8-jrjhx -- curl -sI --connect-timeout 5 echo-a HTTP/1.1 200 OK X-Powered-By: Express Vary: Origin, Accept-Encoding Access-Control-Allow-Credentials: true Accept-Ranges: bytes Cache-Control: public, max-age=0 Last-Modified: Sat, 26 Oct 1985 08:15:00 GMT ETag: W/"83d-7438674ba0" Content-Type: text/html; charset=UTF-8 Content-Length: 2109 Date: Thu, 03 Sep 2020 01:10:27 GMT Connection: keep-alivepod-to-a-l3-denied-cnp 则是只配置了允许访问 DNS，而未配置允许对 echo-a 的访问
(MoeLove) ➜ ~ kubectl exec pod-to-a-l3-denied-cnp-7f64d7b7c4-fsxrm -- curl -sI --connect-timeout 5 echo-a command terminated with exit code 28可以看到，如果对 Pod 应用了 CiliumNetworkPolicy , 但是未配置对应的允许规则的话，则代表不允许访问。
比如，我们可以使用上面两个配置了 CiliumNetworkPolicy 的 Pod 来访问下公网域名：
(MoeLove) ➜ ~ kubectl exec pod-to-a-allowed-cnp-7b85c8db8-jrjhx -- curl -sI --connect-timeout 5 moelove.info command terminated with exit code 28 (MoeLove) ➜ ~ kubectl exec pod-to-a-l3-denied-cnp-7f64d7b7c4-fsxrm -- curl -sI --connect-timeout 5 moelove.info command terminated with exit code 28可以看到，均不能正常访问。
本节，主要介绍了 Cilium 和 Hubble 等。
通过使用 KIND 创建的 Kubernetes 集群，部署了 Cilium 及其相关组件，并通过一个实例，来展示了通过 hubble observe，Hubble UI 及 Hubble metrics 等方式进行观测。
也通过实际操作，验证了 CiliumNetworkPolicy 的实际效果。
我主要是在为 Docker 写代码的过程中，会涉及到 LSM 及 seccomp 等部分，所以顺便去研究了 eBPF 及其相关技术（后续再分享这部分内容）。
而 Cilium 则是我在 2019 年上半年开始学习和研究的，但正如我在去年的文章 《K8S 生态周报| cilium 1.6 发布 100% kube-proxy 的替代品》[5] 中写的那样：
“这里稍微说几句我关于 Cilium 的看法：
厉不厉害？厉害。
值不值得研究？值得。
会不会放到自己的集群替代 kube-proxy ？不会，最起码目前不会。
如果你想要通过 cilium 研究 eBPF 或者 XDP 我倒是建议你可以看看，是个很不错的项目，而且通过这个项目能加深很多网络方面的认识。这么说吧，如果把 cilium 的源码及所涉及原理都研究通透了，那就很厉害了。
至于要不要替换 kube-proxy 在我看来，最起码目前我不会这样去做。解决问题的办法有很多种，而替换掉一个核心组件，却不一定是一个最值得的选择。
”Cilium 是一个值得学习和研究的项目/技术，但我目前尚未将它放到生产环境中（这也是我少数花费很多精力研究，但未应用于生产的技术之一）。
但现在看来， Cilium 也有了一定的市场/发展，是时候重新考量下了。后续我会继续分享 Cilium 及 eBPF 相关的技术文章，欢迎关注。
欢迎订阅我的文章公众号【MoeLove】
[1]
Google 选择 Cilium 作为 GKE 下一代数据面: https://zhuanlan.zhihu.com/p/195759300
[2]Kubernetes IN Docker: https://kind.sigs.k8s.io/
[3]Helm v2 进入维护期倒计时: https://zhuanlan.zhihu.com/p/186265631
[4]connectivity-check: https://raw.githubusercontent.com/cilium/cilium/HEAD/examples/kubernetes/connectivity-check/connectivity-check.yaml
[5]K8S 生态周报| cilium 1.6 发布 100% kube-proxy 的替代品: https://zhuanlan.zhihu.com/p/79757835
