kube-proxy by using IPVS with least connection (lc) scheduler

a bit old story ,but I need to do it anyway.

$ lsmod |grep ip_vs_lc
ip_vs_lc               16384  6
ip_vs                 155648  14 ip_vs_rr,ip_vs_sh,ip_vs_wrr,ip_vs_lc

First you need ipvs installed and loaded ip_vs_lc kernel module.

$ k describe cm -n kube-system kube-proxy |grep -E -A5 "^ipvs"
ipvs:
  excludeCIDRs: null
  minSyncPeriod: 0s
  scheduler: lc 
  strictARP: false
  syncPeriod: 30s

you also need to update kube-proxy config map scheduler=lc

# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.96.0.1:443 lc
  -> 192.168.0.161:6443           Masq    1      7          0         
TCP  10.96.0.10:53 lc
  -> 10.168.75.65:53              Masq    1      0          0         
  -> 10.168.75.66:53              Masq    1      0          0         
TCP  10.96.0.10:9153 lc
  -> 10.168.75.65:9153            Masq    1      0          0         
  -> 10.168.75.66:9153            Masq    1      0          0         
TCP  10.96.243.234:80 lc
  -> 10.168.114.129:8080          Masq    1      0          0         
  -> 10.168.114.131:8080          Masq    1      0          0    

verify the result with ipvsadm command.

10.96.x.x = svc CIDR and 10.168.x.x = pod CIDR

lc at the end of line means this svc IP have least connection (lc) scheduler.

Remember, the least connection schedule scope is only on local worker not cluster level.

that’s all.