Fix kubelet failure fallback and make port configurable

[2opremio]

Fixes #2258 (problem introduced by #2132 ) and adds a new flag to configure kubelet's port (--probe.kubernetes.kubelet-port)

@errordeveloper Can you please test this in Openshift in these two scenarios?

1. Without setting the kubelet port appropriately (to make sure the fallback works)
2. Setting the kubelet port appropriately

[errordeveloper]

1. Without setting the kubelet port appropriately (to make sure the fallback works)

It works:

2. Setting the kubelet port appropriately

As I've pointed out in #2258 (comment), I don't think changing port will help anything, but I can try.

[errordeveloper]

So with --probe.kubernetes.kubelet-port=10250 it still takes the fallback code path and logs this:

<probe> WARN: 2017/03/08 17:40:02.163794 Cannot obtain local pods, reporting all (which may impact performance): Get http://localhost:10250/pods/: malformed HTTP response "\x15\x03\x01\x00\x02\x02"

[2opremio]

Huh, didn't you say that it uses HTTPS? Maybe that's why.

…

On Mar 8, 2017 18:42, "Ilya Dmitrichenko" ***@***.***> wrote: So with --probe.kubernetes.kubelet-port=10250 it still takes the fallback code path and logs this: <probe> WARN: 2017/03/08 17:40:02.163794 Cannot obtain local pods, reporting all (which may impact performance): Get http://localhost:10250/pods/: malformed HTTP response "\x15\x03\x01\x00\x02\x02" — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#2309 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ACQOJDShBsSfmvJKPqXEcp0eA3nqOsssks5rjuh0gaJpZM4MVe43> .

[errordeveloper]

Yeah, I said it is HTTPS.