Automatic merge from submit-queue (batch tested with PRs 39311, 39226, 39445)

Make kubectl proxy accept empty path

**What this PR does / why we need it**:
The kubectl proxy previously returned 403 Forbidden: Unauthorized when receiving a request from e.g. "curl localhost:8001" or "curl localhost:8001/".  The previous DefaultPathAcceptRE regex was wrong as it assumed the path in this case would be "/" (but it is actually "").

After someone runs kubectl proxy and tries accessing it with curl, they will probably just try hitting localhost:8001  (which returns an "Unauthorized" response) instead of say localhost:8001/api (which returns a proper response from the API server). Also, whoever previously modified the DefaultPathAcceptRE regex was obviously expecting the regex to accept requests for localhost:8001/

```release-note
fix issue with kubectl proxy so that it will proxy an empty path - e.g. http://localhost:8001
```

Automatic merge from submit-queue

Check if pathExists before performing Unmount

Unmount operation should not fail if path does not exist

Part two of: https://github.com/kubernetes/kubernetes/pull/38547
Plugins status captured here: https://github.com/kubernetes/kubernetes/issues/39251

cc: @saad-ali

Automatic merge from submit-queue (batch tested with PRs 36229, 39450)

Bugfix on kubeadm join with non-token discovery.

Without this change, using a non-token discovery mechanism during a join triggers a nil pointer panic (instead of an error message about not being implemented yet).

CC @mikedanese 

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

Automatic merge from submit-queue (batch tested with PRs 36229, 39450)

Bump etcd to 3.0.14 and switch to v3 API in etcd.

Ref #20504

**Release note**:

```release-note
Switch default etcd version to 3.0.14.
Switch default storage backend flag in apiserver to `etcd3` mode.
```

Automatic merge from submit-queue (batch tested with PRs 39408, 38981)

Remove RBAC UserAll

* Removes special handling of User * subjects in rolebinding matching evaluation
* Converts v1alpha1 rolebindings to `User *` subjects to `Group system:authenticated` subjects for backwards compatibility

```release-note
RBAC's special handling of the User subject named "*" in RoleBinding and ClusterRoleBinding objects is being deprecated and will be removed in v1beta1. Existing v1alpha1 role bindings to User "*" will be converted to the group "system:authenticated". To match unauthenticated requests, RBAC role bindings must explicitly bind to the group "system:unauthenticated".
```

Without this change, using a non-token discovery mechanism during a join
triggers a nil pointer panic (instead of an error message about not
being implemented yet).

Automatic merge from submit-queue

Ensure invalid token returns 401 error, not 403

fixes #39267

If a user attempts to use a bearer token, and the token is rejected, the authenticator should return an error. This distinguishes requests that did not provide a bearer token (and are unauthenticated without error) from ones that attempted to, and failed.

Automatic merge from submit-queue

snip links from genericapiserver to api/validation

We had a trip dependency on `pkg/api/validation` through `pkg/api/rest` which is used for RESTStorage.  This splits the generic validation required for a genericapiserver out from the rest of validation.  For now, functions still delegate.

@sttts

Automatic merge from submit-queue

Adding test-federation-cmd.sh to test kubectl with federation apiserver

There are 2 parts to the PR:
* Adding ability to run kubectl tests for a subset of resources.
* Adding test-federation-cmd.sh that runs kubectl tests for resources that are supported by federation-apiserver.

cc @kubernetes/sig-federation @kubernetes/sig-api-machinery 

```release-note
Adding kubectl tests for federation
```

Automatic merge from submit-queue

Start moving genericapiserver to staging

This moves `pkg/auth/user` to `staging/k8s.io/genericapiserver/pkg/authentication/user`.  I'll open a separate pull into the upstream gengo to support using `import-boss` on vendored folders to support staging.

After we agree this is the correct approach and see everything build, I'll start moving other packages over which don't have k8s.io/kubernetes deps.

@kubernetes/sig-api-machinery-misc @lavalamp 
@sttts @caesarxuchao ptal

Automatic merge from submit-queue

pkg/labels: fix the godoc for Parse()

previously the formatting was broken for labels.Parse() function. I
fixed the spacing so it will format correctly for the generated go docs.
There was also a dangling "]" at the end of the first line so i deleted
it.



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

This fixes a formatting issue with the generated go documentation.

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

**Release note**:

```release-note
NONE
```

Automatic merge from submit-queue

make discovery static when extensions/thirdpartyresources is not enabled

this should be a bug fix, if `extensions/thirdpartyresources` is enabled, the result of `Discovery().ServerPreferredNamespacedResources` will be dynamic then, so we are making the `discoverResourcesFn` static only when the `extensions/thirdpartyresources` is not enabled.

Automatic merge from submit-queue

add some specifications on the top command

**What this PR does / why we need it**:
the top command is available when heapster works fine on the server, but the specifications doesn't mention about this. So I added some specifications here.

Automatic merge from submit-queue (batch tested with PRs 39409, 39400)

fix wrong help message for taint

fix #39381

Automatic merge from submit-queue (batch tested with PRs 39409, 39400)

remove newAPIGroupVersion() and getAPIGroupVersion() second return value

Automatic merge from submit-queue (batch tested with PRs 38084, 39306)

Small improve for GetContainerOOMScoreAdjust

In `GetContainerOOMScoreAdjust`, make logic more clear for the case `oomScoreAdjust >= besteffortOOMScoreAdj`. If `besteffortOOMScoreAdj`  is defined to another value(e.g. 996), suppose `oomScoreAdjust` is 999, the function will return 998(which equals 999 - 1) instead of 995(996 -1).

Automatic merge from submit-queue

Fix comment and optimize code

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

Fix comment and optimize code.

Thanks.

**Special notes for your reviewer**:

**Release note**:

```release-note
```

Automatic merge from submit-queue

Share rc cache from the rc manager

@kubernetes/sig-apps-misc @hodovska

Automatic merge from submit-queue

Remove jobs that do not exist from active list of CronJob

**What this PR does / why we need it**: This PR modifies the controller for CronJob to remove from the active job list any job that does not exist anymore, to avoid staying blocked in active state forever. See #37957.

**Which issue this PR fixes**: fixes #37957 

**Special notes for your reviewer**:

**Release note**:

```
```

Automatic merge from submit-queue (batch tested with PRs 39405, 39371)

hack/local-up-cluster.sh: fix typo in error message

This commit fixes typo in error message and also removes stale comment from `hack/local-up-cluster.sh`.

Automatic merge from submit-queue (batch tested with PRs 36087, 39405)

federation-apiserver doesn't needs cluster-ip range

This option has been removed from genericserver options
and it is not being used by federation-apiserver anyways.

Fixes - #39388

Automatic merge from submit-queue

oidc auth-n plugin: enforce email_verified claim

This change causes the OpenID Connect authenticator to start
enforcing the 'email_verified' claim.

https://openid.net/specs/openid-connect-core-1_0.html#StandardClaims

If the OIDC authenticator uses the 'email' claim as a user's username
and the 'email_verified' is not set to `true`, reject that authentication attempt.

cc @erictune @kubernetes/sig-auth @mlbiam

```release-note
When using OIDC authentication and specifying --oidc-username-claim=email, an `"email_verified":true` claim must be returned from the identity provider.
```

Automatic merge from submit-queue

Include swaggerapi urls in system:discovery role

Used by client side API validation and for client schema generation

Automatic merge from submit-queue

Remove DockerLegacyService comment from kubelet

Automatic merge from submit-queue (batch tested with PRs 38433, 36245)

Allow pods to define multiple environment variables from a whole ConfigMap

Allow environment variables to be populated from ConfigMaps

- ConfigMaps represent an entire set of EnvVars
- EnvVars can override ConfigMaps


fixes #26299

Automatic merge from submit-queue (batch tested with PRs 38433, 36245)

Remove needless env var in OpenStack provider

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

If we use openstack provider to set up k8s cluster using kube-up script,
`TENANT_ID` environment variable is needed.
But to configure `TENANT_ID` is very annoying because this value is not static by each env.
This patch uses `TENANT_NAME` instead of `TENANT_ID`

**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
```

Since `TENANT_NAME` is unique if we use keystone v2 api,
so `TENANT_ID` is not needed if `TENANT_NAME` is provided
to configure OpenStack provider.
And also to set `TENANT_ID` is annoying to develop, because
`TENANT_ID` is not static by each environment.
This patch remove dependency of `TENANT_ID` and simply use
`TENANT_NAME`.

Since newAPIGroupVersion() and getAPIGroupVersion() will never return err,we do not need that

Automatic merge from submit-queue

add rules not allow message when authorize failed

old result:
```
# ./cluster/kubectl.sh --token=/test get po
Error from server (Forbidden): User "" cannot list pods in the namespace "default".: "<nil>" (get pods)
```
new result:
```
# ./cluster/kubectl.sh --token=/test get po
Error from server (Forbidden): User "" cannot list pods in the namespace "default".: "rules not allow" (get pods)
```

test.yaml
```
kind: Role
apiVersion: rbac.authorization.k8s.io/v1alpha1
metadata:
  name: test
rules:
- apiGroups: ["*"]
  verbs: ["create"]
  resources: ["*"]
---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1alpha1
metadata:
  name: admin-resource-binding
subjects:
  - kind: Group
    name: test
roleRef:
  kind: Role
  name: test
```

This option has been removed from genericserver options
and it is not being used by federation-apiserver anyways.

Fixes - #39388

Automatic merge from submit-queue (batch tested with PRs 39284, 39367)

e2e: Use sudo to start/stop kubelet service

It seems that user 'jenkins' does not have permissions to manage services. sudo is already used to e.g. check iptables in https://github.com/kubernetes/kubernetes/blob/master/test/e2e/service.go#L402

Fixes #37956

Automatic merge from submit-queue (batch tested with PRs 39284, 39367)

Remove HostRecord annotation (beta feature)

The annotation has made it to GA so this code should be deleted.

**Release note**:
```release-note
The 'endpoints.beta.kubernetes.io/hostnames-map' annotation is no longer supported.  Users can use the 'Endpoints.subsets[].addresses[].hostname' field instead.
```