Kubernetes 当中启用IPVS模式

kubernetes启用ipvs模式 （以kubeadm安装的集群为例）

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 启用ipvs而不使用iptables的原因

• ipvs 可以更快地重定向流量，并且在同步代理规则时具有更好的性能。此外，ipvs 为负载均衡算法提供了更
• 多选项，例如：

1. rr ：轮询调度
2. lc ：最小连接数
3. dh ：目标哈希
4. sh ：源哈希
5. sed ：最短期望延迟
6. nq ： 不排队调度

 每个节点都进行如下操作：

安装ipvs相关软件包

yum -y install ipvsadm ipset

modprobe ip_vs

lsmod | grep ip_vs

修改内核参数

vi /etc/sysctl.conf 添加

net.ipv4.ip_forward = 1
net.bridge.bridge-nf-call-iptables = 1
net.bridge.bridge-nf-call-ip6tables = 1


# 应用生效
sysctl -p

修改kube-proxy模式

kubectl edit configmap -n kube-system kube-proxy

    mode: "ipvs"
    nodePortAddresses: null


如果要修改调度算法使用
    scheduler: ""

默认为空 

[root@k8s-master ~]# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn

依次重启/删除kube-proxy的pod 

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Kubeadm不仅仅将k8s集群搭建简化了，还采用了容器化的方式去部署k8s组件，这里只需要知道采用了容器化部署，因为帮我们封装好了。唯一一个采用的不是容器化部署的是kubelete，这个使用的是传统的systemd去管理的，在宿主机进行管理。其他的都是采用容器化部署，也就是通过启动容器帮你拉起组件。

[root@k8s-master ~]# kubectl get pod -n kube-system -o wide
NAME                                       READY   STATUS    RESTARTS   AGE     IP                NODE         NOMINATED NODE   READINESS GATES        1/1     Running   6          2d12h   192.168.179.102   k8s-master              
kube-proxy-7wgls                           1/1     Running   2          2d11h   192.168.179.103   k8s-node1               
kube-proxy-vkt7g                           1/1     Running   3          2d11h   192.168.179.104   k8s-node2               
kube-proxy-xth6p                           1/1     Running   2          2d12h   192.168.179.102   k8s-master              

删除pod之后 会新起一个新的pod 

[root@k8s-master ~]# kubectl delete pod kube-proxy-7wgls -n kube-system 
pod "kube-proxy-7wgls" deleted
[root@k8s-master ~]# kubectl delete pod kube-proxy-vkt7g -n kube-system 
pod "kube-proxy-vkt7g" deleted
[root@k8s-master ~]# kubectl delete pod kube-proxy-xth6p -n kube-system 
pod "kube-proxy-xth6p" deleted

等容器重启完毕再去看看

[root@k8s-master ~]# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  127.0.0.1:32567 rr
  -> 10.244.169.137:80            Masq    1      0          0         
TCP  172.17.0.1:31332 rr
  -> 10.244.169.139:80            Masq    1      0          0         
TCP  172.17.0.1:31383 rr
  -> 10.244.169.138:8443          Masq    1      0          0         
TCP  172.17.0.1:32567 rr
  -> 10.244.169.137:80            Masq    1      0          0         
TCP  192.168.179.102:31332 rr
  -> 10.244.169.139:80            Masq    1      0          0         
TCP  192.168.179.102:31383 rr
  -> 10.244.169.138:8443          Masq    1      0          0         
TCP  192.168.179.102:32567 rr
  -> 10.244.169.137:80            Masq    1      0          0         
TCP  10.96.0.1:443 rr
  -> 192.168.179.102:6443         Masq    1      0          0         
TCP  10.96.0.10:53 rr
  -> 10.244.36.73:53              Masq    1      0          0         
  -> 10.244.36.75:53              Masq    1      0          0         
TCP  10.96.0.10:9153 rr
  -> 10.244.36.73:9153            Masq    1      0          0         
  -> 10.244.36.75:9153            Masq    1      0          0         
TCP  10.98.137.105:80 rr
  -> 10.244.169.137:80            Masq    1      0          0         
TCP  10.99.50.2:80 rr
  -> 10.244.169.139:80            Masq    1      0          0         
TCP  10.99.68.0:443 rr
  -> 192.168.179.103:4443         Masq    1      0          0         
TCP  10.106.187.194:443 rr
  -> 10.244.169.138:8443          Masq    1      0          0         
TCP  10.108.138.194:8000 rr
  -> 10.244.36.74:8000            Masq    1      0          0         
TCP  127.0.0.1:31332 rr
  -> 10.244.169.139:80            Masq    1      0          0         
TCP  127.0.0.1:31383 rr
  -> 10.244.169.138:8443          Masq    1      0          0         
UDP  10.96.0.10:53 rr
  -> 10.244.36.73:53              Masq    1      0          0         
  -> 10.244.36.75:53              Masq    1      0          0   


TCP  172.17.0.1:31332 rr
  -> 10.244.169.139:80            Masq    1      0          0 

[root@k8s-master ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   10.96.0.1            443/TCP        2d12h
nginx        NodePort    10.99.50.2           80:31332/TCP   2d11h 

[root@k8s-master ~]# kubectl get pod -o wide
NAME                     READY   STATUS    RESTARTS   AGE   IP               NODE        NOMINATED NODE   READINESS GATES
nginx-6799fc88d8-mkq8g   1/1     Running   0          10m   10.244.169.139   k8s-node2