Merge pull request #28143 from xiangpengzhao/service-node-port-range

Automatic merge from submit-queue

Should set default value for --service-node-port-range flag before verifying

For the flag `--service-node-port-range` of kube-apiserver, we know that it defaults to `30000-32767` if not specified. But if we only pass the flag `--kubernetes-service-node-port` with a valid value between `30000-32767` when starting kube-apiserver, a fatal error will occurs as the last below. It means that service port range is not 30000-32767 but empty. The log is from code [DefaultAndValidateRunOptions-->ValidateRunOptions-->verifyServiceNodePort](https://github.com/xiangpengzhao/kubernetes/blob/master/pkg/genericapiserver/genericapiserver.go#L580) where the flags are verified. 

After tracing the apiserver related code, we can find the call stack:
```
func main() {
	......
	s := options.NewAPIServer()
	......
	app.Run(s)
	......
}
```
In the `app.Run`, it calls [genericapiserver.DefaultAndValidateRunOptions(s.ServerRunOptions)](https://github.com/xiangpengzhao/kubernetes/blob/master/cmd/kube-apiserver/app/server.go#L80). But the `--kubernetes-service-node-port` hasn't been defaulted before there, so it's empty. It's then defaulted in `app.Run`-->[master.New](https://github.com/xiangpengzhao/kubernetes/blob/master/cmd/kube-apiserver/app/server.go#L276)-->[genericapiserver.New](https://github.com/xiangpengzhao/kubernetes/blob/master/pkg/master/master.go#L179)-->[setDefaults](https://github.com/xiangpengzhao/kubernetes/blob/master/pkg/genericapiserver/genericapiserver.go#L338)-->[defaultServiceNodePortRange](https://github.com/xiangpengzhao/kubernetes/blob/master/pkg/genericapiserver/genericapiserver.go#L281).

So, we have to set default value for `--kubernetes-service-node-port` in [NewServerRunOptions](https://github.com/xiangpengzhao/kubernetes/blob/master/pkg/genericapiserver/options/server_run_options.go#L105), as is done for `--secure-port` and/or `--insecure-port`. The `NewServerRunOptions` will be called in options.[NewAPIServer](https://github.com/xiangpengzhao/kubernetes/blob/master/cmd/kube-apiserver/app/options/options.go#L50)().

Hope that I have described the issue clearly. Thanks!

```
root@vm:~# kube-apiserver --etcd-servers=http://172.16.1.11:4001 --service-cluster-ip-range=192.168.122.0/24 --insecure-bind-address=0.0.0.0 --logtostderr=false --log-dir=/home/paas/zxp/log/kube --v=10 --kubernetes-service-node-port=30001 &
[2] 24629
root@vm:~# F0627 23:46:37.308726   24629 genericapiserver.go:580] Kubernetes service port range  doesn't contain 30001
goroutine 1 [running]:
k8s.io/kubernetes/vendor/github.com/golang/glog.stacks(0x44f2500, 0x0, 0x0, 0x0)
	/home/paas/zxp/code/k8s/fork/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/github.com/golang/glog/glog.go:766 +0xb8
k8s.io/kubernetes/vendor/github.com/golang/glog.(*loggingT).output(0x44d2020, 0xc800000003, 0xc820238000, 0x438c73b, 0x13, 0x244, 0x0)
	/home/paas/zxp/code/k8s/fork/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/github.com/golang/glog/glog.go:717 +0x259
k8s.io/kubernetes/vendor/github.com/golang/glog.(*loggingT).printf(0x44d2020, 0xc800000003, 0x3223dc0, 0x33, 0xc8204c4cc8, 0x2, 0x2)
	/home/paas/zxp/code/k8s/fork/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/github.com/golang/glog/glog.go:655 +0x1d4
k8s.io/kubernetes/vendor/github.com/golang/glog.Fatalf(0x3223dc0, 0x33, 0xc8204c4cc8, 0x2, 0x2)
	/home/paas/zxp/code/k8s/fork/kubernetes/_output/local/go/src/k8s.io/kubernetes/vendor/github.com/golang/glog/glog.go:1145 +0x5d
k8s.io/kubernetes/pkg/genericapiserver.verifyServiceNodePort(0xc8202a8400)
	/home/paas/zxp/code/k8s/fork/kubernetes/_output/local/go/src/k8s.io/kubernetes/pkg/genericapiserver/genericapiserver.go:580 +0x1d5
k8s.io/kubernetes/pkg/genericapiserver.ValidateRunOptions(0xc8202a8400)
	/home/paas/zxp/code/k8s/fork/kubernetes/_output/local/go/src/k8s.io/kubernetes/pkg/genericapiserver/genericapiserver.go:605 +0x2f
k8s.io/kubernetes/pkg/genericapiserver.DefaultAndValidateRunOptions(0xc8202a8400)
	/home/paas/zxp/code/k8s/fork/kubernetes/_output/local/go/src/k8s.io/kubernetes/pkg/genericapiserver/genericapiserver.go:612 +0x4e
k8s.io/kubernetes/cmd/kube-apiserver/app.Run(0xc820224fc0, 0x0, 0x0)
	/home/paas/zxp/code/k8s/fork/kubernetes/_output/local/go/src/k8s.io/kubernetes/cmd/kube-apiserver/app/server.go:80 +0x70
main.main()
	/home/paas/zxp/code/k8s/fork/kubernetes/_output/local/go/src/k8s.io/kubernetes/cmd/kube-apiserver/apiserver.go:50 +0x121

[2]+  Exit 255                kube-apiserver --etcd-servers=http://172.16.1.11:4001 --service-cluster-ip-range=192.168.122.0/24 --insecure-bind-address=0.0.0.0 --logtostderr=false --log-dir=/home/paas/zxp/log/kube --v=10 --kubernetes-service-node-port=30001
root@vm:~#

```

pkg/genericapiserver/options/server_run_options.go

@@ -133,6 +133,7 @@ func NewServerRunOptions() *ServerRunOptions {
 		MinRequestTimeout:       1800,
 		RuntimeConfig:           make(config.ConfigurationMap),
 		SecurePort:              6443,
+		ServiceNodePortRange:    utilnet.PortRange{Base: 30000, Size: 2768},
 		StorageVersions:         registered.AllPreferredGroupVersions(),
 	}
 }