kubelet: Incorrect fallback to hairpin-mode "hairpin-veth"

[NikolayMurha]

Hi guys. I have issue with connecting to PODs itself via service ip.
I determined that the problem with the wrong fallback to harpin-veth.

In kubelet output I have message:

W0322 09:27:09.399179   25899 kubelet.go:508] Hairpin mode set to "promiscuous-bridge" but configureCBR0 is false, falling back to "hairpin-veth"
I0322 09:27:09.399219   25899 kubelet.go:380] Hairpin mode set to "hairpin-veth"

But hairpin_mode for interfaces is 0:

cat /sys/devices/virtual/net/docker0/brif/veth*/hairpin_mode
0
0
0
0

If I set kubelet --hairpin-mod=hairpin-veth all is ok.

Kubelet output

I0322 09:29:08.234951   28239 kubelet.go:380] Hairpin mode set to "hairpin-veth"

and

cat /sys/devices/virtual/net/docker0/brif/veth*/hairpin_mode
1
1
1
1

I think problem is there
https://github.com/kubernetes/kubernetes/blob/master/pkg/kubelet/kubelet.go#L408
Because used hairpinMode variable, but value was set above to klet.hairpinMode (https://github.com/kubernetes/kubernetes/blob/master/pkg/kubelet/kubelet.go#L378) .

[NikolayMurha]

Fix #23325

[bprashanth]

Closed via #23325
@MurgaNikolay thanks for the fix