make NSC set net.ipv4.vs.conn_reuse_mode=0

[roffe]

will fix the IPVS low throughput issues

kubernetes/kubernetes#71114

[andrewsykim]

Do we need to check if conn_reuse_mode is available first? It seems like it was introduced in linux 4.1.

[roffe]

@andrewsykim glansing over the code from K8S i can't rly say they do:

https://github.com/Lion-Wei/kubernetes/blob/f39060c6047b8dce5af197a97d5f18422d93c9d1/pkg/proxy/ipvs/proxier.go

[roffe]

now we check and inform that it's a non fatal error if not there
if there is a error statting the file we also inform and continue as it's non-fatal

[murali-reddy]

thanks @roffe

[roffe]

i'm fixing it with a pr