I have kubernetes 1.11 cluster with 26 nodes and 3 master all servers running on Centos 7 OS, its running for a while. recently I noticed kube-api server establishing too many connection to node kubelet port 10250. today its used all the ports on the primary master, helm command started failing. I have restart some nodes to clean up the ports

tcp        0      0 xx.xx.xx3.53:50863     xx.xx.xx4.94:10250     ESTABLISHED
tcp        0      0 xx.xx.xx3.53:60531     xx.xx.xx3.62:10250     ESTABLISHED
tcp        0      0 xx.xx.xx3.53:42625     xx.xx.xx3.63:10250     ESTABLISHED
tcp        0      0 xx.xx.xx3.53:56703     xx.xx.xx3.61:10250     ESTABLISHED
tcp        0      0 xx.xx.xx3.53:49426     xx.xx.xx3.64:10250     ESTABLISHED

all the nodes it used 50 thousand ports

netstat -an |grep -ci estab
51163

I like to know why kube-api creating too many connection to kubelet. how to resolve this issue.

Thanks SR