聊聊Kubernetes Without Kube-Proxy

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引言

最近听好多朋友说,聊聊cilium很强,聊聊势必将成为主流。聊聊因其使用了ebpf,聊聊性能好,聊聊而且支持网络策略。聊聊于是聊聊,决定花点时间学习一下。聊聊在通过官网文档学习过程中,聊聊发现使用cilium作为CNI,聊聊居然可以不用安装kube-proxy了。聊聊这让我想起来,聊聊之前在面试中被问到的一个问题,面试官问我:kube-proxy是否可以不用安装,是否有其他替代品。这下不就有答案了嘛。云南idc服务商

顺便吐槽一下,看官方文档学习,是真的有点难(毕竟全英文);不过还是建议大家看官方文档学习,不要翻译成中文哦。那么接下来,就由我来实操一下。

环境说明

序号 事项 说明 1 kubernetes version v1.21.3 2 cilium version v1.10.3 3 kubernetes安装方式 kubeadm 4 cilium组网模式 vxlan 5 os ubuntu 18.04 6 kubernetes集群规模 1master、2node

正文

在master上初始化集群,并通过添加--skip-phases=addon/kube-proxy参数忽略kube-proxy的安装

kubeadm init   --apiserver-advertise-address=10.211.55.50   --image-repository registry.aliyuncs.com/google_containers   --kubernetes-version v1.21.3   --service-cidr=10.96.0.0/12   --pod-network-cidr=10.244.0.0/16   --ignore-preflight-errors=all --skip-phases=addon/kube-proxy 

在两个node上执行kubeadm join,加入集群

kubeadm join 10.211.55.50:6443 --token ouez6j.02ms269v8i4psl7p --discovery-token-ca-cert-hash sha256:5fdafe0fe1adb3b60cd7bc33f033f028279a94a3944816424cc7f5bb498f6868 

使用helm(v3)来安装cilium。先添加cilium库

helm repo add cilium https://helm.cilium.io/ 

使用如下命令安装cilium,添加kubeProxyReplacement=strict参数

helm install cilium cilium/cilium --version 1.10.3     --namespace kube-system     --set kubeProxyReplacement=strict     --set k8sServiceHost=10.211.55.50     --set k8sServicePort=6443 

检查cilium安装结果

# 查看cilium agent,以daemonset方式部署在每个node节点上 root@cilium1:/# kubectl -n kube-system get pods -l k8s-app=cilium NAME           READY   STATUS    RESTARTS   AGE cilium-8gwg2   1/1     Running   0          8m4s cilium-t9ffc   1/1     Running   0          8m39s cilium-x42r6   1/1     Running   0          8m16s # 查看cilum operator root@cilium1:~# kubectl get po -A -o wide |grep cilium-operator kube-system   cilium-operator-5df88875-867hd    1/1     Running   5          41h   172.16.88.47    cilium3   <none>           <none> kube-system   cilium-operator-5df88875-9kx8c    1/1     Running   5          41h   172.16.88.253   cilium2   <none>           <none> 

检查是否有kube-proxy组件。可以发现并没有该组件

root@cilium1:/# kubectl get po -n kube-system NAME                              READY   STATUS    RESTARTS   AGE cilium-8gwg2                      1/1     Running   0          10m cilium-operator-5df88875-867hd    1/1     Running   5          27h cilium-operator-5df88875-9kx8c    1/1     Running   5          27h cilium-t9ffc                      1/1     Running   0          11m cilium-x42r6                      1/1     Running   0          10m coredns-59d64cd4d4-hbwg4          1/1     Running   1          27h coredns-59d64cd4d4-l2pmt          1/1     Running   1          27h etcd-cilium1                      1/1     Running   2          27h kube-apiserver-cilium1            1/1     Running   2          27h kube-controller-manager-cilium1   1/1     Running   2          27h kube-scheduler-cilium1            1/1     Running   2          27h 

检查cilium状态,确保安装正确

root@cilium1:/# kubectl exec -n kube-system  cilium-t9ffc  -- cilium status Defaulted container "cilium-agent" out of: cilium-agent, mount-cgroup (init), clean-cilium-state (init) KVStore:                Ok   Disabled Kubernetes:             Ok   1.21 (v1.21.3) [linux/amd64] Kubernetes APIs:        ["cilium/v2::CiliumClusterwideNetworkPolicy", "cilium/v2::CiliumEndpoint", "cilium/v2::CiliumNetworkPolicy", "cilium/v2::CiliumNode", "core/v1::Namespace", "core/v1::Node", "core/v1::Pods", "core/v1::Service", "discovery/v1::EndpointSlice", "networking.k8s.io/v1::NetworkPolicy"] KubeProxyReplacement:   Strict   [eth0 10.211.55.50 (Direct Routing)] Cilium:                 Ok   1.10.3 (v1.10.3-4145278) NodeMonitor:            Listening for events on 8 CPUs with 64x4096 of shared memory Cilium health daemon:   Ok    IPAM:                   IPv4: 2/254 allocated from 10.0.0.0/24,  BandwidthManager:       Disabled Host Routing:           Legacy Masquerading:           BPF   [eth0]   10.0.0.0/24 [IPv4: Enabled, IPv6: Disabled] Controller Status:      20/20 healthy Proxy Status:           OK, ip 10.0.0.41, 0 redirects active on ports 10000-20000 Hubble:                 Ok   Current/Max Flows: 817/4095 (19.95%), Flows/s: 0.95   Metrics: Disabled Encryption:             Disabled Cluster health:         3/3 reachable   (2021-08-07T15:29:05Z) 

部署nginx来测试一下网络联通性

# nginx deployment yaml文件 cat deployment-nginx.yaml apiVersion: apps/v1 kind: Deployment metadata:   name: nginx spec:   selector:     matchLabels:       run: nginx   replicas: 4   template:     metadata:       labels:         run: nginx     spec:       containers:       - name: nginx         image: nginx         ports:         - containerPort: 80 # 创建nginx deployment kubectl create -f deployment-nginx.yaml # 查看部署结果 root@cilium1:/# kubectl get po -o wide NAME                     READY   STATUS    RESTARTS   AGE   IP           NODE      NOMINATED NODE   READINESS GATES nginx-649c4b9857-8f2v5   1/1     Running   1          26h   10.0.2.212   cilium2   <none>           <none> nginx-649c4b9857-mhsxs   1/1     Running   1          26h   10.0.1.23    cilium3   <none>           <none> nginx-649c4b9857-qw2jj   1/1     Running   1          26h   10.0.2.69    cilium2   <none>           <none> nginx-649c4b9857-vj9w2   1/1     Running   1          26h   10.0.1.126   cilium3 

创建一个nodeport service来验证service的可访问

# 创建service kubectl expose deployment nginx --type=NodePort --port=80 # 查看service root@cilium1:/# kubectl get svc nginx NAME    TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE nginx   NodePort   10.97.209.103   <none>        80:31126/TCP   26h 

验证nodeport、cluster可访问

# 通过nodeport root@cilium1:/# curl 127.0.0.1:31126 <!DOCTYPE html> <html> <head> <title>Welcome to nginx!</title> # 通过service:port root@cilium1:/# curl 10.97.209.103 <!DOCTYPE html> <html> <head> <title>Welcome to nginx!</title> # 检查iptables 发现为空 root@cilium1:/# iptables-save | grep KUBE-SVC root@cilium1:/#  # 检查ciliun service root@cilium1:/# kubectl exec -n kube-system  cilium-t9ffc  -- cilium service list Defaulted container "cilium-agent" out of: cilium-agent, mount-cgroup (init), clean-cilium-state (init) ID   Frontend             Service Type   Backend                   1    10.96.0.1:443        ClusterIP      1 => 172.16.88.57:6443    2    10.96.0.10:9153      ClusterIP      1 => 10.0.2.229:9153                                               2 => 10.0.2.80:9153       3    10.96.0.10:53        ClusterIP      1 => 10.0.2.229:53                                                 2 => 10.0.2.80:53         4    10.97.209.103:80     ClusterIP      1 => 10.0.2.69:80                                                  2 => 10.0.1.23:80                                                  3 => 10.0.1.126:80                                                 4 => 10.0.2.212:80        5    172.16.88.57:31126   NodePort       1 => 10.0.2.69:80                                                  2 => 10.0.1.23:80                                                  3 => 10.0.1.126:80                                                 4 => 10.0.2.212:80        6    0.0.0.0:31126        NodePort       1 => 10.0.2.69:80                                                  2 => 10.0.1.23:80                                                  3 => 10.0.1.126:80                                                 4 => 10.0.2.212:80        

从上面的安装和测试结果来,服务器租用虽然我们没有安装k8s的kube-proxy组件,但是集群依然正常。说明kube-proxy组件确实是可以被替代的。

总结

以上虽然完成了kubernetes without kube-proxy的搭建和测试工作,但还是有很多事情没说明。比如使用cilium的系统要求、cilium是什么、有几种组网模式、网络策略。不过请不要着急,期待我后续的文章。

参考

https://docs.cilium.io/en/v1.10/gettingstarted/kubeproxy-free/#kubernetes-without-kube-proxy

https://kubernetes.io/docs/concepts/cluster-administration/addons/

https://helm.sh/docs/intro/install/

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