Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
pkg/api: extract Scheme/Registry/Codecs into pkg/api/legacyscheme
This serves as
- a preparation for the pkg/api->pkg/apis/core move
- and makes the dependency to the scheme explicit when vizualizing
left depenncies.
The later helps with our our efforts to split up the monolithic repo
into self-contained sub-repos, e.g. for kubectl, controller-manager
and kube-apiserver in the future.
The client cert manager uses the most recent cert to request new
certificates. If that certificate is expired, it will be unable to
complete new CSR requests. This commit alters the manager to force
process exit if no further client cert rotation is possible, which
is expected to trigger a restart of the kubelet and either a
re-bootstrap from the bootstrap kubeconfig or a re-read of the
current disk state (assuming that some other agent is managing the
bootstrap configuration).
This prevents the Kubelet from wedging in a state where it cannot make
API calls.
Revert "Merge pull request #51857 from kubernetes/revert-51307-kc-type-refactor"
This reverts commit 9d27d92420, reversing
changes made to 2e69d4e625.
See original: #51307
We punted this from 1.8 so it could go through an API review. The point
of this PR is that we are trying to stabilize the kubeletconfig API so
that we can move it out of alpha, and unblock features like Dynamic
Kubelet Config, Kubelet loading its initial config from a file instead
of flags, kubeadm and other install tools having a versioned API to rely
on, etc.
We shouldn't rev the version without both removing all the deprecated
junk from the KubeletConfiguration struct, and without (at least
temporarily) removing all of the fields that have "Experimental" in
their names. It wouldn't make sense to lock in to deprecated fields.
"Experimental" fields can be audited on a 1-by-1 basis after this PR,
and if found to be stable (or sufficiently alpha-gated), can be restored
to the KubeletConfiguration without the "Experimental" prefix.
Command line flag API remains the same. This allows ComponentConfig
structures (e.g. KubeletConfiguration) to express the map structure
behind feature gates in a natural way when written as JSON or YAML.
For example:
KubeletConfiguration Before:
```
apiVersion: kubeletconfig/v1alpha1
kind: KubeletConfiguration
featureGates: "DynamicKubeletConfig=true,Accelerators=true"
```
KubeletConfiguration After:
```
apiVersion: kubeletconfig/v1alpha1
kind: KubeletConfiguration
featureGates:
DynamicKubeletConfig: true
Accelerators: true
```
This is part of the move to external cloud providers. Please see
plan detail in issue 50986. This PR covers step #2:
v1.9 - set no cloud provider as the default in kubelet but still allow
opt in for auto-detect
Automatic merge from submit-queue (batch tested with PRs 44596, 52708, 53163, 53167, 52692). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Fix --kube-reserved storage key name and add UTs for node allocatable reservation
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: part of #52463
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
/assign @jingxu97
Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Add version info to kube-scheduler, kube-proxy and kubelet logs.
**What this PR does / why we need it**:
#46047 add such info to apiserver and CM. This adds version info to other binaries.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: related to #46047
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Update kubelet's 'pod-manifest-path' description
Improved grammer of flag `pod-manifest-path` of kubelet
**What this PR does / why we need it**:
It updates the flag description which had an extra `to`, so this commit removes it.
/approve no-issue
```release-note
NONE
```
Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>..
kubelet: remove the --docker-exec-handler flag
Stop supporting the "nsenter" exec handler. Only the Docker native exec
handler is supported.
The flag was deprecated in Kubernetes 1.6 and is safe to remove
in Kubernetes 1.9 according to the deprecation policy.
**What this PR does / why we need it**:
**Which issue this PR fixes** : fixes#40229
**Special notes for your reviewer**:
N/A
**Release note**:
```release-note
Remove the --docker-exec-handler flag. Only native exec handler is supported.
```
Automatic merge from submit-queue (batch tested with PRs 52485, 52443, 52597, 52450, 51971). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>..
Some kubelet flags do not accept their default values
Correct the flags and add a round trip test that ensure these do not
break again in the future.
@deads2k as observed when we tried to turn flags into args.
Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>..
remove duplicated import
**What this PR does / why we need it**:
**Which issue this PR fixes** : fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
Stop supporting the "nsenter" exec handler. Only the Docker native exec
handler is supported.
The flag was deprecated in Kubernetes 1.6 and is safe to remove
in Kubernetes 1.9 according to the deprecation policy.
Automatic merge from submit-queue (batch tested with PRs 51728, 49202)
Enable CRI-O stats from cAdvisor
**What this PR does / why we need it**:
cAdvisor may support multiple container runtimes (docker, rkt, cri-o, systemd, etc.)
As long as the kubelet continues to run cAdvisor, runtimes with native cAdvisor support may not want to run multiple monitoring agents to avoid performance regression in production. Pending kubelet running a more light-weight monitoring solution, this PR allows remote runtimes to have their stats pulled from cAdvisor when cAdvisor is registered stats provider by introspection of the runtime endpoint.
See issue https://github.com/kubernetes/kubernetes/issues/51798
**Special notes for your reviewer**:
cAdvisor will be bumped to pick up https://github.com/google/cadvisor/pull/1741
At that time, CRI-O will support fetching stats from cAdvisor.
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue (batch tested with PRs 51984, 51351, 51873, 51795, 51634)
Revert to using isolated PID namespaces in Docker
**What this PR does / why we need it**: Reverts to the previous docker default of using isolated PID namespaces for containers in a pod. There exist container images that expect always to be PID 1 which we want to support unmodified in 1.8.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes#48937
**Special notes for your reviewer**:
**Release note**:
```release-note
Sharing a PID namespace between containers in a pod is disabled by default in 1.8. To enable for a node, use the --docker-disable-shared-pid=false kubelet flag. Note that PID namespace sharing requires docker >= 1.13.1.
```
A shared PID namespace were enabled by default in the 1.7 when running
with a supported Docker runtime, but a Docker version that supports
a shared namespace was not qualified for use.
Release 1.8 will qualify a docker version supporting shared PID, but we
don't want to cause disruption for container images which expect always
to have PID 1.
Automatic merge from submit-queue (batch tested with PRs 49971, 51357, 51616, 51649, 51372)
Separate feature gates for dynamic kubelet config vs loading from a file
This makes it so these two features can be turned on independently, rather than bundling both under dynamic kubelet config.
fixes: #51664
```release-note
NONE
```
Automatic merge from submit-queue (batch tested with PRs 50932, 49610, 51312, 51415, 50705)
Deprecation warnings for auto detecting cloud providers
**What this PR does / why we need it**:
Adds deprecation warnings for auto detecting cloud providers. As part of the initiative for out-of-tree cloud providers, this feature is conflicting since we're shifting the dependency of kubernetes core into cAdvisor. In the future kubelets should be using `--cloud-provider=external` or no cloud provider at all.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes#50986
**Special notes for your reviewer**:
NOTE: I still have to coordinate with sig-node and kubernetes-dev to get approval for this deprecation, I'm only opening this PR since we're close to code freeze and it's something presentable.
**Release note**:
```release-note
Deprecate auto detecting cloud providers in kubelet. Auto detecting cloud providers go against the initiative for out-of-tree cloud providers as we'll now depend on cAdvisor integrations with cloud providers instead of the core repo. In the near future, `--cloud-provider` for kubelet will either be an empty string or `external`.
```
Automatic merge from submit-queue (batch tested with PRs 51054, 51101, 50031, 51296, 51173)
Dynamic Flexvolume plugin discovery, probing with filesystem watch.
**What this PR does / why we need it**: Enables dynamic Flexvolume plugin discovery. This model uses a filesystem watch (fsnotify library), which notifies the system that a probe is necessary only if something changes in the Flexvolume plugin directory.
This PR uses the dependency injection model in https://github.com/kubernetes/kubernetes/pull/49668.
**Release Note**:
```release-note
Dynamic Flexvolume plugin discovery. Flexvolume plugins can now be discovered on the fly rather than only at system initialization time.
```
/sig-storage
/assign @jsafrane @saad-ali
/cc @bassam @chakri-nelluri @kokhang @liggitt @thockin
Automatic merge from submit-queue (batch tested with PRs 50889, 51347, 50582, 51297, 51264)
Change eviction manager to manage one single local storage resource
**What this PR does / why we need it**:
We decided to manage one single resource name, eviction policy should be modified too.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: part of #50818
**Special notes for your reviewer**:
**Release note**:
```release-note
Change eviction manager to manage one single local ephemeral storage resource
```
/assign @jingxu97
The ReadOnlyPort defaulting prevented passing 0 to diable via
the KubeletConfiguraiton struct.
The HealthzPort defaulting prevented passing 0 to disable via the
KubeletConfiguration struct. The documentation also failed to mention
this, but the check is performed in code.
The CAdvisorPort documentation failed to mention that you can pass 0 to
disable.
This reverts commit f4afdecef8, reversing
changes made to e633a1604f.
This also fixes a bug where Kubemark was still using the core api scheme
to manipulate the Kubelet's types, which was the cause of the initial
revert.
Automatic merge from submit-queue (batch tested with PRs 50119, 48366, 47181, 41611, 49547)
Fail on swap enabled and deprecate experimental-fail-swap-on flag
**What this PR does / why we need it**:
* Deprecate the old experimental-fail-swap-on
* Add a new flag fail-swap-on and set it to true
Before this change, we would not fail when swap is on. With this
change we fail for everyone when swap is on, unless they explicitly
set --fail-swap-on to false.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
Fixes#34726
**Special notes for your reviewer**:
**Release note**:
```release-note
Kubelet will by default fail with swap enabled from now on. The experimental flag "--experimental-fail-swap-on" has been deprecated, please set the new "--fail-swap-on" flag to false if you wish to run with /proc/swaps on.
```
* Deprecate the old experimental-fail-swap-on
* Add a new flag fail-swap-on and set it to true
Before this change, we would not fail when swap is on. With this
change we fail for everyone when swap is on, unless they explicitly
set --fail-swap-on to false.
After the kubelet rotates its client cert, it will keep connections
to the API server open indefinitely, causing it to use its old
credentials instead of the new certs
When the kubelet rotates its cert, close down existing connections
to force a new TLS handshake.
Automatic merge from submit-queue (batch tested with PRs 49538, 49708, 47665, 49750, 49528)
Use the core client with version
**What this PR does / why we need it**:
Replace the **deprecated** `clientSet.Core()` with `clientSet.CoreV1()`.
**Which issue this PR fixes**: fixes#49535
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue (batch tested with PRs 45813, 49594, 49443, 49167, 47539)
Deprecate keep-terminated-pod-volumes
It was discussed and agreed by sig-storage that
this flag causes unnecessary confusion and is hard to keep
synchornized with controller's attach/detach functionality.
Fixes https://github.com/kubernetes/kubernetes/issues/45615
```release-note
keep-terminated-pod-volumes flag on kubelet is deprecated.
```
Automatic merge from submit-queue (batch tested with PRs 49238, 49595, 43494, 47897, 48905)
Should not set struct pointer directly to interface which may cause potential panic
fix https://github.com/kubernetes/kubernetes/issues/43127 to avoid potential kubelet panic.
In our old implemention, interface `kubeDeps.EventClient ` (interface) will never equals to `nil` even if `eventClient `(struct pointer )was set to `nil`. `kubeDeps.ExternalKubeClient` and `kubeDeps.KubeClient` also have same potential risk.
Automatic merge from submit-queue (batch tested with PRs 48976, 49474, 40050, 49426, 49430)
Use presence of kubeconfig file to toggle standalone mode
Fixes#40049
```release-note
The deprecated --api-servers flag has been removed. Use --kubeconfig to provide API server connection information instead. The --require-kubeconfig flag is now deprecated. The default kubeconfig path is also deprecated. Both --require-kubeconfig and the default kubeconfig path will be removed in Kubernetes v1.10.0.
```
/cc @kubernetes/sig-cluster-lifecycle-misc @kubernetes/sig-node-misc
Automatic merge from submit-queue (batch tested with PRs 48976, 49474, 40050, 49426, 49430)
Remove duplicated import and wrong alias name of api package
**What this PR does / why we need it**:
**Which issue this PR fixes**: fixes#48975
**Special notes for your reviewer**:
/assign @caesarxuchao
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue
Remove flags low-diskspace-threshold-mb and outofdisk-transition-frequency
issue: #48843
This removes two flags replaced by the eviction manager. These have been depreciated for two releases, which I believe correctly follows the kubernetes depreciation guidelines.
```release-note
Remove depreciated flags: --low-diskspace-threshold-mb and --outofdisk-transition-frequency, which are replaced by --eviction-hard
```
cc @mtaufen since I am changing kubelet flags
cc @vishh @derekwaynecarr
/sig node
Automatic merge from submit-queue (batch tested with PRs 48636, 49088, 49251, 49417, 49494)
Fix issues for local storage allocatable feature
This PR fixes the following issues:
1. Use ResourceStorageScratch instead of ResourceStorage API to represent
local storage capacity
2. In eviction manager, use container manager instead of node provider
(kubelet) to retrieve the node capacity and reserved resources. Node
provider (kubelet) has a feature gate so that storagescratch information
may not be exposed if feature gate is not set. On the other hand,
container manager has all the capacity and allocatable resource
information.
This PR fixes issue #47809
Replaces use of --api-servers with --kubeconfig in Kubelet args across
the turnup scripts. In many cases this involves generating a kubeconfig
file for the Kubelet and placing it in the correct location on the node.
This PR fixes the following issues:
1. Use ResourceStorageScratch instead of ResourceStorage API to represent
local storage capacity
2. In eviction manager, use container manager instead of node provider
(kubelet) to retrieve the node capacity and reserved resources. Node
provider (kubelet) has a feature gate so that storagescratch information
may not be exposed if feature gate is not set. On the other hand,
container manager has all the capacity and allocatable resource
information.
This is used by integrators that want to perform partial overrides of
key interfaces. Refactors the run() method to fit the existing style and
preserve the existing behavior, but allow (for instance) client
bootstrap and cert refresh even when some dependencies are injected.
Automatic merge from submit-queue (batch tested with PRs 47694, 47772, 47783, 47803, 47673)
Make different container runtimes constant
Make different container runtimes constant to avoid hardcode
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue (batch tested with PRs 47915, 47856, 44086, 47575, 47475)
kubelet should resume csr bootstrap
Right now the kubelet creates a new csr object with the same key every
time it restarts during the bootstrap process. It should resume with the
old csr object if it exists. To do this the name of the csr object must
be stable.
Issue https://github.com/kubernetes/kubernetes/issues/47855
Automatic merge from submit-queue (batch tested with PRs 47922, 47195, 47241, 47095, 47401)
Run cAdvisor on the same interface as kubelet
**What this PR does / why we need it**:
cAdvisor currently binds to all interfaces. Currently the only
solution is to use iptables to block access to the port. We
are better off making cAdvisor to bind to the interface that
kubelet uses for better security.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
Fixes#11710
**Special notes for your reviewer**:
**Release note**:
```release-note
cAdvisor binds only to the interface that kubelet is running on instead of all interfaces.
```
Right now the kubelet creates a new csr object with the same key every
time it restarts during the bootstrap process. It should resume with the
old csr object if it exists. To do this the name of the csr object must
be stable. Also using a list watch here eliminates a race condition
where a watch event is missed and the kubelet stalls.
Automatic merge from submit-queue (batch tested with PRs 46327, 47166)
Fixed typo in comments.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes # N/A
```release-note
NONE
```
Automatic merge from submit-queue (batch tested with PRs 46327, 47166)
mark --network-plugin-dir deprecated for kubelet
**What this PR does / why we need it**:
**Which issue this PR fixes** : fixes#43967
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
It was discussed and agreed by sig-storage that
this flag causes unnecessary confusion and is hard to keep
synchornized with controller's attach/detach functionality.
cAdvisor currently binds to all interfaces. Currently the only
solution is to use iptables to block access to the port. We
are better off making cAdvisor to bind to the interface that
kubelet uses for better security.
Fixes#11710
Automatic merge from submit-queue (batch tested with PRs 43005, 46660, 46385, 46991, 47103)
Consolidate sysctl commands for kubelet
**What this PR does / why we need it**:
These commands are important enough to be in the Kubelet itself.
By default, Ubuntu 14.04 and Debian Jessie have these set to 200 and
20000. Without this setting, nodes are limited in the number of
containers that they can start.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes#26005
**Special notes for your reviewer**:
I had a difficult time writing tests for this. It is trivial to create a fake sysctl for testing, but the Kubelet does not have any tests for the prior settings.
**Release note**:
```release-note
```
Automatic merge from submit-queue (batch tested with PRs 46972, 42829, 46799, 46802, 46844)
promote tls-bootstrap to beta
last commit of this PR.
Towards https://github.com/kubernetes/kubernetes/issues/46999
```release-note
Promote kubelet tls bootstrap to beta. Add a non-experimental flag to use it and deprecate the old flag.
```
Automatic merge from submit-queue
Add local storage (scratch space) allocatable support
This PR adds the support for allocatable local storage (scratch space).
This feature is only for root file system which is shared by kubernetes
componenets, users' containers and/or images. User could use
--kube-reserved flag to reserve the storage for kube system components.
If the allocatable storage for user's pods is used up, some pods will be
evicted to free the storage resource.
This feature is part of local storage capacity isolation and described in the proposal https://github.com/kubernetes/community/pull/306
**Release note**:
```release-note
This feature exposes local storage capacity for the primary partitions, and supports & enforces storage reservation in Node Allocatable
```
Automatic merge from submit-queue (batch tested with PRs 46726, 41912, 46695, 46034, 46551)
Rotate kubelet client certificate.
Changes the kubelet so it bootstraps off the cert/key specified in the
config file and uses those to request new cert/key pairs from the
Certificate Signing Request API, as well as rotating client certificates
when they approach expiration.
Default behavior is for client certificate rotation to be disabled. If enabled
using a command line flag, the kubelet exits each time the certificate is
rotated. I tried to use `GetCertificate` in [tls.Config](https://golang.org/pkg/crypto/tls/#Config) but it is only called
on the server side of connections. Then I tried `GetClientCertificate`,
but it is new in 1.8.
**Release note**
```release-note
With --feature-gates=RotateKubeletClientCertificate=true set, the kubelet will
request a client certificate from the API server during the boot cycle and pause
waiting for the request to be satisfied. It will continually refresh the certificate
as the certificates expiration approaches.
```
Automatic merge from submit-queue (batch tested with PRs 46801, 45184, 45930, 46192, 45563)
adds log when --kubeconfig with wrong config
**What this PR does / why we need it**:
easy for troubleshooting
I have set --kubeconfig==/etc/kubernetes/kubelet.conf when copy & paste(the file path is wrong “==/etc/kubernetes/kubelet.conf”), but kubelet start with no error log. I don't know what happend.
**Release note**:
```release-note
NONE
```
This PR adds the check for local storage request when admitting pods. If
the local storage request exceeds the available resource, pod will be
rejected.
This PR adds the support for allocatable local storage (scratch space).
This feature is only for root file system which is shared by kubernetes
componenets, users' containers and/or images. User could use
--kube-reserved flag to reserve the storage for kube system components.
If the allocatable storage for user's pods is used up, some pods will be
evicted to free the storage resource.
Changes the kubelet so it bootstraps off the cert/key specified in the
config file and uses those to request new cert/key pairs from the
Certificate Signing Request API, as well as rotating client certificates
when they approach expiration.
Automatic merge from submit-queue (batch tested with PRs 46076, 43879, 44897, 46556, 46654)
Local storage plugin
**What this PR does / why we need it**:
Volume plugin implementation for local persistent volumes. Scheduler predicate will direct already-bound PVCs to the node that the local PV is at. PVC binding still happens independently.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*:
Part of #43640
**Release note**:
```
Alpha feature: Local volume plugin allows local directories to be created and consumed as a Persistent Volume. These volumes have node affinity and pods will only be scheduled to the node that the volume is at.
```
Automatic merge from submit-queue (batch tested with PRs 46635, 45619, 46637, 45059, 46415)
Certificate rotation for kubelet server certs.
Replaces the current kubelet server side self signed certs with certs signed by
the Certificate Request Signing API on the API server. Also renews expiring
kubelet server certs as expiration approaches.
Two Points:
1. With `--feature-gates=RotateKubeletServerCertificate=true` set, the kubelet will
request a certificate during the boot cycle and pause waiting for the request to
be satisfied.
2. In order to have the kubelet's certificate signing request auto approved,
`--insecure-experimental-approve-all-kubelet-csrs-for-group=` must be set on
the cluster controller manager. There is an improved mechanism for auto
approval [proposed](https://github.com/kubernetes/kubernetes/issues/45030).
**Release note**:
```release-note
With `--feature-gates=RotateKubeletServerCertificate=true` set, the kubelet will
request a server certificate from the API server during the boot cycle and pause
waiting for the request to be satisfied. It will continually refresh the certificate as
the certificates expiration approaches.
```
Automatic merge from submit-queue
kubelet: group all container-runtime-specific flags/options into a separate struct
They don't belong in the KubeletConfig.
This addresses #43253
Automatic merge from submit-queue
fixtypo
**What this PR does / why we need it**:
fix typo seperated -> separated
**Release note**:
```release-note
None
```
Replaces the current kubelet server side self signed certs with certs
signed by the Certificate Request Signing API on the API server. Also
renews expiring kubelet server certs as expiration approaches.
Automatic merge from submit-queue
Enable shared PID namespace by default for docker pods
**What this PR does / why we need it**: This PR enables PID namespace sharing for docker pods by default, bringing the behavior of docker in line with the other CRI runtimes when used with docker >= 1.13.1.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: ref #1615
**Special notes for your reviewer**: cc @dchen1107 @yujuhong
**Release note**:
```release-note
Kubernetes now shares a single PID namespace among all containers in a pod when running with docker >= 1.13.1. This means processes can now signal processes in other containers in a pod, but it also means that the `kubectl exec {pod} kill 1` pattern will cause the pod to be restarted rather than a single container.
```
Automatic merge from submit-queue (batch tested with PRs 45453, 45307, 44987)
Migrate the docker client code from dockertools to dockershim
Move docker client code from dockertools to dockershim/libdocker. This includes
DockerInterface (renamed to Interface), FakeDockerClient, etc.
This is part of #43234
Automatic merge from submit-queue (batch tested with PRs 45362, 45159, 45321, 45238)
expose kubelet authentication and authorization builders
The kubelet authentication and authorization builder methods are useful for consumers.
@liggitt
Automatic merge from submit-queue
kubelet/get-pods-from-path: correct description of implemention
**What this PR does / why we need it**:
I find this description does not follow the current implementation, it should be describe like this according to my understanding of the source code.
These commands are important enough to be in the Kubelet itself.
By default, Ubuntu 14.04 and Debian Jessie have these set to 200 and
20000. Without this setting, nodes are limited in the number of
containers that they can start.
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
Add dockershim only mode
This PR added a `experimental-dockershim` hidden flag in kubelet to run dockershim only.
We introduce this flag mainly for cri validation test. In the future we should compile dockershim into another binary.
@yujuhong @feiskyer @xlgao-zju
/cc @kubernetes/sig-node-pr-reviews