Automatic merge from submit-queue

Delete "hard-coded" default value in flags usage.

**What this PR does / why we need it**:
Some flags of kubernetes components have "hard-coded" default values in their usage info. In fact, [pflag pkg](https://github.com/kubernetes/kubernetes/blob/master/vendor/github.com/spf13/pflag/flag.go#L602-L608) has already added a string `(default value)` automatically in the usage info if the flag is initialized. Then we don't need to hard-code the default value in usage info. After this PR, if we want to update the default value of a flag, we only need to update the flag where it is initialized. `pflag` will update the usage info for us. This will avoid inconsistency.

For example:
Before
```
kubelet -h
...
--node-status-update-frequency duration                   Specifies how often kubelet posts node status to master. Note: be cautious when changing the constant, it must work with nodeMonitorGracePeriod in nodecontroller. Default: 10s (default 10s)
...
```

After
```
kubelet -h
...
--node-status-update-frequency duration                   Specifies how often kubelet posts node status to master. Note: be cautious when changing the constant, it must work with nodeMonitorGracePeriod in nodecontroller. (default 10s)
...
```

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:
This PR doesn't delete some "hard-coded" default values because they are not explicitly initialized. We still need to hard-code them to give users friendly info.

```
--allow-privileged                                        If true, allow containers to request privileged mode. [default=false]
```

**Release note**:

```release-note
None
```

Automatic merge from submit-queue (batch tested with PRs 41583, 45117, 45123)

Allow `make test-integration` to pass on OSX

**What this PR does / why we need it**: `make test-integration` isn't passing on my OSX setup (10.11.6, go1.8.1, 17.05.0-ce-rc1).  Tests that startup an api server fail because the default `cert-dir` of `/var/run/kubernetes` isn't world-writable.  Use a tempdir instead.

**Release note**:
```release-note
NONE
```

ref: #41595

/cc @kubernetes/sig-testing-pr-reviews

Automatic merge from submit-queue (batch tested with PRs 41583, 45117, 45123)

Adds the cifs-common package

**What this PR does / why we need it**:  Enables mounting of CIFS volumes. Required for Azure.

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes https://github.com/juju-solutions/bundle-canonical-kubernetes/issues/227

**Release note**:

```release-note
Added CIFS PV support for Juju Charms
```

Automatic merge from submit-queue (batch tested with PRs 41583, 45117, 45123)

Implement shared PID namespace in the dockershim

**What this PR does / why we need it**: Defaults the Docker CRI to using a shared PID namespace for pods. Implements proposal in https://github.com/kubernetes/community/pull/207 tracked by #1615.

//cc @dchen1107 @vishh @timstclair 

**Special notes for your reviewer**: none

**Release note**:
```release-note
Some container runtimes share a process (PID) namespace for all containers in a pod. This will become the default for Docker in a future release of Kubernetes. You can preview this functionality if running with the CRI and Docker 1.13.1 by enabling the --experimental-docker-enable-shared-pid kubelet flag.
```

Automatic merge from submit-queue

Remove rkouj from owners files.

Remove inactive member, @rkouj, from storage owners files.

CC @rkouj

Automatic merge from submit-queue

Stackdriver test fix

Extend timeout & add logging missing metrics

Automatic merge from submit-queue

Quote groups in deny log message

Helps distinguish cases where an external authenticator is incorrectly combining multiple groups into one.

Before:
> RBAC DENY: user "bob" groups [system:masters view system:authenticated] cannot "list" resource "pods" cluster-wide

After:
> RBAC DENY: user "bob" groups ["system:masters view" "system:authenticated"] cannot "list" resource "pods" cluster-wide

Automatic merge from submit-queue (batch tested with PRs 44044, 44766, 44930, 45109, 43301)

add APIService conditions

Adds conditions to the APIServiceStatus struct and fixes up generators that appear to have slipped.

The first condition is "ServiceAvailable" which will provide the status currently derived in the discovery handler that decides about whether to expose the version in discovery.

@kubernetes/sig-api-machinery-pr-reviews @liggitt @ncdc

Automatic merge from submit-queue (batch tested with PRs 44044, 44766, 44930, 45109, 43301)

e2e test: test azure disk volume

**What this PR does / why we need it**:
E2E test Azure disk volume
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:
@kubernetes/sig-testing-pr-reviews 

**Release note**:
```release-note
NONE
```

Automatic merge from submit-queue (batch tested with PRs 44044, 44766, 44930, 45109, 43301)

Fixes get -oname for unstructured objects

Fixes https://github.com/kubernetes/kubernetes/issues/44832

Make sure we display kind in `kubectl get -o name` for unknown resource types.

**Release note**:

```release-note
NONE
```

Automatic merge from submit-queue (batch tested with PRs 44044, 44766, 44930, 45109, 43301)

Reduce lock contention in KubeProxy

Automatic merge from submit-queue

e2e: Remove special serviceaccount permission requirement

**What this PR does / why we need it**:

This removes the requirement for having a `default` serviceaccount with permission `create` `pod` in order to run the prestop e2e conformance test.

The `create` `pod` permissions are not needed for this particular test, and having it effectively means that as cluster must have a `default` serviceaccount with `create` `pod` permissions in order to be conformant, which I don't think is desired.

**Special notes for your reviewer**:

**Release note**:

```release-note
None
```

update busybox to fix build

`/var/run` is not world-writable on my OSX 10.11.x setup, so tests that
standup a secure apiserver fail with the default cert dir.  Use a
tempdir instead.

Automatic merge from submit-queue

Remove the Rackspace provider

**What this PR does / why we need it**:

To aid the effort of moving providers out of the cluster dir, I'm
removing Rackspace and leaving behind a README.md simply as a
placeholder until the entire dir is deleted.

**Which issue this PR fixes**

Fixes #6962

**Release note**:

```release-note
Deployment of Kubernetes clusters on Rackspace using the in-tree bash deployment (i.e. cluster/kube-up.sh or get-kube.sh) is obsolete and support has been removed.```

Automatic merge from submit-queue

Log warning when invalid dir passed to kubectl proxy --www

**Release note**:

```
Log warning when invalid directory is passed to `kubectl proxy --www`
```

Automatic merge from submit-queue (batch tested with PRs 45033, 44961, 45021, 45097, 44938)

Cleanup orphan logging that goes on in the sync loop.

**What this PR does / why we need it**:

Fixes #44937  

**Before this PR** The older logs were like this:

```
E0426 00:06:33.763347   21247 kubelet_volumes.go:114] Orphaned pod "35c4a858-2a12-11e7-910c-42010af00003" found, but volume paths are still present on disk.
E0426 00:06:33.763400   21247 kubelet_volumes.go:114] Orphaned pod "e7676365-1580-11e7-8c27-42010af00003" found, but volume paths are still present on disk.
```

The problem being that, all the volumes were spammed w/ no summary info.   

**After this PR** the logs look like this:

```
E0426 01:32:27.295568   22261 kubelet_volumes.go:129] Orphaned pod "408b060e-2a1d-11e7-90e8-42010af00003" found, but volume paths are still present on disk. : There were a total of 2 errors similar to this.  Turn up verbosity to see them.
E0426 01:32:29.295515   22261 kubelet_volumes.go:129] Orphaned pod "408b060e-2a1d-11e7-90e8-42010af00003" found, but volume paths are still present on disk. : There were a total of 2 errors similar to this.  Turn up verbosity to see them.
E0426 01:32:31.293180   22261 kubelet_volumes.go:129] Orphaned pod "408b060e-2a1d-11e7-90e8-42010af00003" found, but volume paths are still present on disk. : There were a total of 2 errors similar to this.  Turn up verbosity to see them.
```

And with logging turned up, the extra info logs are shown with details:

```
E0426 01:34:21.933983   26010 kubelet_volumes.go:129] Orphaned pod "1c565800-2a20-11e7-bbc2-42010af00003" found, but volume paths are still present on disk. : There were a total of 3 errors similar to this.  Turn up verbosity to see them.
I0426 01:34:21.934010   26010 kubelet_volumes.go:131] Orphan pod: Orphaned pod "1c565800-2a20-11e7-bbc2-42010af00003" found, but volume paths are still present on disk.
I0426 01:34:21.934015   26010 kubelet_volumes.go:131] Orphan pod: Orphaned pod "408b060e-2a1d-11e7-90e8-42010af00003" found, but volume paths are still present on disk.
I0426 01:34:21.934019   26010 kubelet_volumes.go:131] Orphan pod: Orphaned pod "e7676365-1580-11e7-8c27-42010af00003" found, but volume paths are still present on disk.
```

**Release note**

```release-note
Roll up volume error messages in the kubelet sync loop.
```

Automatic merge from submit-queue (batch tested with PRs 45033, 44961, 45021, 45097, 44938)

Disable the kubelet part of metrics collection in kubemark

Fixes https://github.com/kubernetes/kubernetes/issues/45038

This should fix it, as we are just interested in getting the apiserver metrics from kubemark master.

cc @wojtek-t @gmarek

Automatic merge from submit-queue (batch tested with PRs 45033, 44961, 45021, 45097, 44938)

Add request count to APICall metric

Ref https://github.com/kubernetes/kubernetes/issues/44701

This should add beside the API call latencies, the count of the requests.

cc @wojtek-t @gmarek

Automatic merge from submit-queue (batch tested with PRs 45033, 44961, 45021, 45097, 44938)

replace CloneTLSConfig() with (*tls.Config).Clone()

Automatic merge from submit-queue

Prune examples and e2es per discussion on sig-testing

**What this PR does / why we need it**:
Prune k8petstore from examples and e2es per discussion on sig-testing

**Special notes for your reviewer**:
This can live elsewhere outside the main repository.  

**Release note**:

```
NONE
```

/cc @jayunit100 @fejta @kubernetes/sig-testing-pr-reviews

Automatic merge from submit-queue

kubectl binary plugins

**What this PR does / why we need it**:

Introduces the ability to extend `kubectl` by adding third-party plugins that will be exposed through `kubectl`.

Plugins are executable commands written in any language. To be included as a plugin, a binary or script file has to

1. be located under one of the supported plugin path locations:
1.1 `~/.kubectl/plugins` dir
1.2. one or more directory set in the `KUBECTL_PLUGINS_PATH` env var
1.3. the `kubectl/plugins` dir under one or more directory set in the `XDG_DATA_DIRS` env var, which defaults to `/usr/local/share:/usr/share`
2. in any of the plugin path above, have a subfolder with the plugin file(s)
3. in the subfolder, contain at least a `plugin.yaml` file that describes the plugin

Example:

```
$ cat ~/.kube/plugins/myplugin/plugin.yaml
name: "myplugin"
shortDesc: "My plugin's short description"
command: "echo Hello plugins!"

$ kubectl myplugin
Hello plugins!
```

~~In case the plugin declares `tunnel: true`, the plugin engine will pass the `KUBECTL_PLUGIN_API_HOST` env var when calling the plugin binary. Plugins can then access the Kube REST API in "http://$KUBECTL_PLUGIN_API_HOST/api" using the same context currently in use by `kubectl`.~~

Test plugins are provided in `pkg/kubectl/plugins/examples`. Just copy (or symlink) the files to `~/.kube/plugins` to test.

**Which issue this PR fixes**:

Related to the discussions in the proposal document: https://github.com/kubernetes/kubernetes/pull/30086 and https://github.com/kubernetes/community/pull/122.

**Release note**:
```release-note
Introduces the ability to extend kubectl by adding third-party plugins. Developer preview, please refer to the documentation for instructions about how to use it.
```

Signed-off-by: Huamin Chen <hchen@redhat.com>

Enable mounting of filesystems over the CIFS protocol. Closes
https://github.com/juju-solutions/bundle-canonical-kubernetes/issues/227

Automatic merge from submit-queue (batch tested with PRs 44868, 44350)

build external watch event so simple encoders can encode

`kube-apiserver` clients require a specific serialization of `watch.Event` to function properly.  There is no reason to allow flexibility of serialization at this point since no client would able to understand a different encoding.

I found this which trying to use a simple, unstructured json encoder and the clients kept choking on watches because it serialized without the proper json tags.

@kubernetes/sig-api-machinery-pr-reviews

Automatic merge from submit-queue

Adding datastore cluster support for dynamic and static pv

**What this PR does / why we need it**:

Customer reported with version 1.4.7 he could use a datastore that is in a cluster as a vsphere volume. When he upgraded to 1.6.0, this same exact path does not work and throws a datastore not found error. 

This PR is adding support to allow using datastore within cluster for volume provisioning.

**Which issue this PR fixes** : 
fixes https://github.com/kubernetes/kubernetes/issues/44007

**Special notes for your reviewer**:

**Created datastore cluster as below.**

![ds-cluster](https://cloud.githubusercontent.com/assets/22985595/25350381/d2652c24-28d9-11e7-8659-097bd9b844bb.jpg)


**Verified  dynamic PV provisioning and pod creation using datastore (sharedVmfs-0) in a cluster (DatastoreCluster).**
```
$ cat thin_sc.yaml 
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: thin
provisioner: kubernetes.io/vsphere-volume
parameters:
    diskformat: thin
    datastore: DatastoreCluster/sharedVmfs-0
```


```
$ kubectl create -f thin_sc.yaml 
storageclass "thin" created
$ kubectl describe storageclass thin
Name:		thin
IsDefaultClass:	No
Annotations:	<none>
Provisioner:	kubernetes.io/vsphere-volume
Parameters:	datastore=DatastoreCluster/sharedVmfs-0,diskformat=thin
No events.
$ 
```


```
$ kubectl create -f thin_pvc.yaml 
persistentvolumeclaim "thinclaim" created
```

```
$ kubectl get pvc
NAME        STATUS    VOLUME                                     CAPACITY   ACCESSMODES   AGE
thinclaim   Bound     pvc-581805e3-290d-11e7-9ad8-005056bd81ef   2Gi        RWO           1m
```

```
$ kubectl get pv
NAME                                       CAPACITY   ACCESSMODES   RECLAIMPOLICY   STATUS    CLAIM               REASON    AGE
pvc-581805e3-290d-11e7-9ad8-005056bd81ef   2Gi        RWO           Delete          Bound     default/thinclaim             1m

```


```
$ kubectl describe pvc thinclaim
Name:		thinclaim
Namespace:	default
StorageClass:	thin
Status:		Bound
Volume:		pvc-581805e3-290d-11e7-9ad8-005056bd81ef
Labels:		<none>
Capacity:	2Gi
Access Modes:	RWO
Events:
  FirstSeen	LastSeen	Count	From				SubObjectPath	Type		Reason			Message
  ---------	--------	-----	----				-------------	--------	------			-------
  39s		39s		1	{persistentvolume-controller }			Normal		ProvisioningSucceeded	Successfully provisioned volume pvc-581805e3-290d-11e7-9ad8-005056bd81ef using kubernetes.io/vsphere-volume
```


```
$ kubectl describe pv pvc-581805e3-290d-11e7-9ad8-005056bd81ef
Name:		pvc-581805e3-290d-11e7-9ad8-005056bd81ef
Labels:		<none>
StorageClass:	
Status:		Bound
Claim:		default/thinclaim
Reclaim Policy:	Delete
Access Modes:	RWO
Capacity:	2Gi
Message:	
Source:
    Type:	vSphereVolume (a Persistent Disk resource in vSphere)
    VolumePath:	[DatastoreCluster/sharedVmfs-0] kubevols/kubernetes-dynamic-pvc-581805e3-290d-11e7-9ad8-005056bd81ef.vmdk
    FSType:	ext4
No events.

```
```

$ kubectl create -f thin_pod.yaml 
pod "thinclaimpod" created
```
```

$ kubectl get pod
NAME           READY     STATUS    RESTARTS   AGE
thinclaimpod   1/1       Running   0          1m
```


```
$ kubectl describe pod thinclaimpod
Name:		thinclaimpod
Namespace:	default
Node:		node3/172.1.56.0
Start Time:	Mon, 24 Apr 2017 09:46:56 -0700
Labels:		<none>
Status:		Running
IP:		172.1.56.3
Controllers:	<none>
Containers:
  test-container:
    Container ID:	docker://487f77d92b92ee3d833b43967c8d42433e61cd45a58d8d6f462717301597c84f
    Image:		gcr.io/google_containers/busybox:1.24
    Image ID:		docker://sha256:0cb40641836c461bc97c793971d84d758371ed682042457523e4ae701efe7ec9
    Port:		
    Command:
      /bin/sh
      -c
      echo 'hello' > /mnt/volume1/index.html  && chmod o+rX /mnt /mnt/volume1/index.html && while true ; do sleep 2 ; done
    State:		Running
      Started:		Mon, 24 Apr 2017 09:47:16 -0700
    Ready:		True
    Restart Count:	0
    Volume Mounts:
      /mnt/volume1 from test-volume (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-cqcq1 (ro)
    Environment Variables:	<none>
Conditions:
  Type		Status
  Initialized 	True 
  Ready 	True 
  PodScheduled 	True 
Volumes:
  test-volume:
    Type:	PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
    ClaimName:	thinclaim
    ReadOnly:	false
  default-token-cqcq1:
    Type:	Secret (a volume populated by a Secret)
    SecretName:	default-token-cqcq1
QoS Class:	BestEffort
Tolerations:	<none>
Events:
  FirstSeen	LastSeen	Count	From			SubObjectPath			Type		Reason		Message
  ---------	--------	-----	----			-------------			--------	------		-------
  40s		40s		1	{default-scheduler }					Normal		Scheduled	Successfully assigned thinclaimpod to node3
  22s		22s		1	{kubelet node3}		spec.containers{test-container}	Normal		Pulling		pulling image "gcr.io/google_containers/busybox:1.24"
  21s		21s		1	{kubelet node3}		spec.containers{test-container}	Normal		Pulled		Successfully pulled image "gcr.io/google_containers/busybox:1.24"
  21s		21s		1	{kubelet node3}		spec.containers{test-container}	Normal		Created		Created container with id 487f77d92b92ee3d833b43967c8d42433e61cd45a58d8d6f462717301597c84f
  21s		21s		1	{kubelet node3}		spec.containers{test-container}	Normal		Started		Started container with id 487f77d92b92ee3d833b43967c8d42433e61cd45a58d8d6f462717301597c84f
```


```
$ kubectl delete pod thinclaimpod
pod "thinclaimpod" deleted
```

Verified Disk is detached from the node

```
$ kubectl delete pvc thinclaim
persistentvolumeclaim "thinclaim" deleted
$ kubectl get pv
No resources found.
```
Verified Disk is deleted from the datastore.
Also verified above life cycle using non clustered datastore.

**Verified Using static PV in the datastore cluster for pod provisioning.**
```
# pwd
/vmfs/volumes/sharedVmfs-0/kubevols
# vmkfstools -c 2g test.vmdk
Create: 100% done
# ls
test-flat.vmdk  test.vmdk
```



```
$ cat pod.yaml 
apiVersion: v1
kind: Pod
metadata:
    name: inject-pod
spec:
    containers:
    - name: test-container
      image: gcr.io/google_containers/busybox:1.24
      command: ["/bin/sh", "-c", "echo 'hello' > /mnt/volume1/index.html  && chmod o+rX /mnt /mnt/volume1/index.html && while true ; do sleep 2 ; done"]
      volumeMounts:
      - name: test-volume
        mountPath: /mnt/volume1
    securityContext:
      seLinuxOptions:
        level: "s0:c0,c1"
    restartPolicy: Never
    volumes:
    - name: test-volume
      vsphereVolume:
          volumePath: "[DatastoreCluster/sharedVmfs-0] kubevols/test.vmdk"
          fsType: ext4
```

```
$ kubectl create -f pod.yaml 
pod "inject-pod" created

$ kubectl get pod
NAME         READY     STATUS    RESTARTS   AGE
inject-pod   1/1       Running   0          19s

$ kubectl describe pod inject-pod
Name:		inject-pod
Namespace:	default
Node:		node3/172.1.56.0
Start Time:	Mon, 24 Apr 2017 10:27:22 -0700
Labels:		<none>
Status:		Running
IP:		172.1.56.3
Controllers:	<none>
Containers:
  test-container:
    Container ID:	docker://ed14e058fbcc9c2d8d30ff67bd614e45cf086afbbff070744c5a461e87c45103
    Image:		gcr.io/google_containers/busybox:1.24
    Image ID:		docker://sha256:0cb40641836c461bc97c793971d84d758371ed682042457523e4ae701efe7ec9
    Port:		
    Command:
      /bin/sh
      -c
      echo 'hello' > /mnt/volume1/index.html  && chmod o+rX /mnt /mnt/volume1/index.html && while true ; do sleep 2 ; done
    State:		Running
      Started:		Mon, 24 Apr 2017 10:27:40 -0700
    Ready:		True
    Restart Count:	0
    Volume Mounts:
      /mnt/volume1 from test-volume (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-cqcq1 (ro)
    Environment Variables:	<none>
Conditions:
  Type		Status
  Initialized 	True 
  Ready 	True 
  PodScheduled 	True 
Volumes:
  test-volume:
    Type:	vSphereVolume (a Persistent Disk resource in vSphere)
    VolumePath:	[DatastoreCluster/sharedVmfs-0] kubevols/test.vmdk
    FSType:	ext4
  default-token-cqcq1:
    Type:	Secret (a volume populated by a Secret)
    SecretName:	default-token-cqcq1
QoS Class:	BestEffort
Tolerations:	<none>
Events:
  FirstSeen	LastSeen	Count	From			SubObjectPath			Type		Reason		Message
  ---------	--------	-----	----			-------------			--------	------		-------
  44s		44s		1	{default-scheduler }					Normal		Scheduled	Successfully assigned inject-pod to node3
  26s		26s		1	{kubelet node3}		spec.containers{test-container}	Normal		Pulled		Container image "gcr.io/google_containers/busybox:1.24" already present on machine
  26s		26s		1	{kubelet node3}		spec.containers{test-container}	Normal		Created		Created container with id ed14e058fbcc9c2d8d30ff67bd614e45cf086afbbff070744c5a461e87c45103
  26s		26s		1	{kubelet node3}		spec.containers{test-container}	Normal		Started		Started container with id ed14e058fbcc9c2d8d30ff67bd614e45cf086afbbff070744c5a461e87c45103
```


**Release note**:

```release-note
none
```

cc: @BaluDontu @moserke @tusharnt @pdhamdhere

Automatic merge from submit-queue

Fix PathPrefix for subresources

before this change:
$ curl -s http://172.16.116.128:8080/api/v1/nodes/kubenet-02/status | grep selfLink
    "selfLink": "/api/v1/nodes/{name}/status/kubenet-02/status",
after this change:
$ curl -s http://172.16.116.128:8080/api/v1/nodes/kubenet-02/status | grep selfLink
    "selfLink": "/api/v1/nodes/kubenet-02/status",

related to:
#44462

**Release note**:

```NONE
```

Automatic merge from submit-queue

taint-controller-tests: double 'a bit of time' to avoid flakes

Automatic merge from submit-queue (batch tested with PRs 41530, 44814, 43620, 41985)

kube-apiserver: improve bootstrap token authentication error messages

This was requested by @jbeda as a follow up to https://github.com/kubernetes/kubernetes/pull/41281.

cc @jbeda @luxas @kubernetes/sig-auth-pr-reviews

Automatic merge from submit-queue (batch tested with PRs 41530, 44814, 43620, 41985)

Fixes juju kubernetes master: 1. Get certs from a dead leader. 2. Append tokens.

**What this PR does / why we need it**:
Fixes two issues with the Juju kubernetes master.

1. Grab certificates from a leader that is already removed.
2. Append (not truncate) auth tokens 

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
fixes #43563 fixes #43519

**Special notes for your reviewer**:

**Release note**:

```
Recover certificates from leadership context in case all masters die in a Juju deployment
```

Automatic merge from submit-queue (batch tested with PRs 41530, 44814, 43620, 41985)

no need check is nil, because has checked before

**What this PR does / why we need it**:

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
```

Automatic merge from submit-queue

rename variables to make sure that they conform to golang variable name conventions

rename variables to make sure that they conform to golang variable name conventions

**What this PR does / why we need it**:

there are lots of package level unexported variables in package `cmd` not conforming golang variable name conventions, such as `version_example`, in this PR i rename all of them to make sure that they conform to golang variable name conventions