This extends the Kubelet to create and periodically update leases in a
new kube-node-lease namespace. Based on [KEP-0009](https://github.com/kubernetes/community/blob/master/keps/sig-node/0009-node-heartbeat.md),
these leases can be used as a node health signal, and will allow us to
reduce the load caused by over-frequent node status reporting.
- add NodeLease feature gate
- add kube-node-lease system namespace for node leases
- add Kubelet option for lease duration
- add Kubelet-internal lease controller to create and update lease
- add e2e test for NodeLease feature
- modify node authorizer and node restriction admission controller
to allow Kubelets access to corresponding leases
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remove unused functions in cmd
**What this PR does / why we need it**:
/kind cleanup
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue (batch tested with PRs 62444, 66358, 66724, 66726). 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>.
Move kubelet serving cert rotation to beta
xref https://github.com/kubernetes/features/issues/267
This is exercised in the alpha gke e2es, and can be enabled in the non-alpha gke e2es once it no longer requires an alpha feature gate.
```release-note
Kubelet serving certificate bootstrapping and rotation has been promoted to beta status.
```
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refactor server.go to simplify the invokes to kubeFlags and KubeConfiguration
**What this PR does / why we need it**:
Since kubeFlags and KubeletConfiguration have been fields of KubeletServer, we just need to pass the reference of KubeletServer to the following functions. This will simplify the migrations of flags such as BootstrapCheckpointPath and others, as we don't have to specify from which object the migrated field comes.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #
**Special notes for your reviewer**:
@mtaufen
**Release note**:
```release-note
NONE
```
The --docker-disable-shared-pid flag has been deprecated since 1.10 and
has been superceded by ShareProcessNamespace in the pod API, which is
scheduled for beta in 1.12.
Automatic merge from submit-queue (batch tested with PRs 65456, 65549). 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 flexvolume in containerized kubelets
Fixes flex volumes in containerized kubelets.
cc @jsafrane @chakri-nelluri @verult
Note to reviewers : e2e tests pass in local containarized cluster.
```release-note
Fix flexvolume in containarized kubelets
```
Automatic merge from submit-queue (batch tested with PRs 61330, 64793, 64675, 65059, 65368). 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 bug: kubelet potential panic
**What this PR does / why we need it**:
fix bug: kubelet may panic calling wg.Done after wg.Wait returned.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
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bind alpha feature network plugin flags correctly
**What this PR does / why we need it**:
When working #63542, I found the flags, like `--cni-conf-dir` and `cni-bin-dir`, were not correctly bound.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #
**Special notes for your reviewer**:
/cc kubernetes/sig-node-pr-reviews
**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>.
remove deprecated option '--enable-custom-metrics'
**Release note**:
```release-note
deprecated and inactive option '--enable-custom-metrics' is removed in 1.11
```
Automatic merge from submit-queue (batch tested with PRs 63348, 63839, 63143, 64447, 64567). 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>.
Containerized subpath
**What this PR does / why we need it**:
Containerized kubelet needs a different implementation of `PrepareSafeSubpath` than kubelet running directly on the host.
On the host we safely open the subpath and then bind-mount `/proc/<pidof kubelet>/fd/<descriptor of opened subpath>`.
With kubelet running in a container, `/proc/xxx/fd/yy` on the host contains path that works only inside the container, i.e. `/rootfs/path/to/subpath` and thus any bind-mount on the host fails.
Solution:
- safely open the subpath and gets its device ID and inode number
- blindly bind-mount the subpath to `/var/lib/kubelet/pods/<uid>/volume-subpaths/<name of container>/<id of mount>`. This is potentially unsafe, because user can change the subpath source to a link to a bad place (say `/run/docker.sock`) just before the bind-mount.
- get device ID and inode number of the destination. Typical users can't modify this file, as it lies on /var/lib/kubelet on the host.
- compare these device IDs and inode numbers.
**Which issue(s) this PR fixes**
Fixes#61456
**Special notes for your reviewer**:
The PR contains some refactoring of `doBindSubPath` to extract the common code. New `doNsEnterBindSubPath` is added for the nsenter related parts.
**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>.
Add proxy for container streaming in kubelet for streaming auth.
For https://github.com/kubernetes/kubernetes/issues/36666, option 2 of https://github.com/kubernetes/kubernetes/issues/36666#issuecomment-378440458.
This PR:
1. Removed the `DirectStreamingRuntime`, and changed `IndirectStreamingRuntime` to `StreamingRuntime`. All `DirectStreamingRuntime`s, `dockertools` and `rkt`, were removed.
2. Proxy container streaming in kubelet instead of returning redirect to apiserver. This solves the container runtime authentication issue, which is what we agreed on in https://github.com/kubernetes/kubernetes/issues/36666.
Please note that, this PR replaced the redirect with proxy directly instead of adding a knob to switch between the 2 behaviors. For existing CRI runtimes like containerd and cri-o, they should change to serve container streaming on localhost, so as to make the whole container streaming connection secure.
If a general authentication mechanism proposed in https://github.com/kubernetes/kubernetes/issues/62747 is ready, we can switch back to redirect, and all code can be found in github history.
Please also note that this added some overhead in kubelet when there are container streaming connections. However, the actual bottleneck is in the apiserver anyway, because it does proxy for all container streaming happens in the cluster. So it seems fine to get security and simplicity with this overhead. @derekwaynecarr @mrunalp Are you ok with this? Or do you prefer a knob?
@yujuhong @timstclair @dchen1107 @mikebrow @feiskyer
/cc @kubernetes/sig-node-pr-reviews
**Release note**:
```release-note
Kubelet now proxies container streaming between apiserver and container runtime. The connection between kubelet and apiserver is authenticated. Container runtime should change streaming server to serve on localhost, to make the connection between kubelet and container runtime local.
In this way, the whole container streaming connection is secure. To switch back to the old behavior, set `--redirect-container-streaming=true` flag.
```
Automatic merge from submit-queue (batch tested with PRs 61803, 64305, 64170, 64361, 64339). 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 a flag to control the cap on images reported in node status
While I normally try to avoid adding flags, this is a short term
scalability fix for v1.11, and there are other long-term solutions in
the works, so we shouldn't commit to this in the v1beta1 Kubelet config.
Flags are our escape hatch here.
```release-note
NONE
```
While I normally try to avoid adding flags, this is a short term
scalability fix for v1.11, and there are other long-term solutions in
the works, so we shouldn't commit to this in the v1beta1 Kubelet config.
Flags are our escape hatch.
Automatic merge from submit-queue (batch tested with PRs 62984, 64304). 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 alpha feature warning for log rotation flags.
CRI container log rotation is beta now.
@yujuhong /cc @mtaufen @kubernetes/sig-node-pr-reviews
Signed-off-by: Lantao Liu <lantaol@google.com>
**Release note**:
```release-note
none
```
Automatic merge from submit-queue (batch tested with PRs 63859, 63979). 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 signal handler registration from pkg/kubelet
**What this PR does / why we need it**:
The goal of this change is to remove the registration of signal
handling from pkg/kubelet (i.e., library code).
If you register a signal handler in `main()` to aid in a controlled
and deliberate exit then the handler registered in `pkg/kubelet` often
wins and the process exits immediately. This means all other signal
handler registrations are currently racy if `DockerServer.Start()` is
directly or indirectly invoked.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #
**Special notes for your reviewer**:
This change also removes another signal handler registration from
`NewAPIServerCommand()`; a stop channel is now passed to this
function.
**Release note**:
The goal of this change is to remove the registration of signal
handling from pkg/kubelet. We now pass in a stop channel.
If you register a signal handler in `main()` to aid in a controlled
and deliberate exit then the handler registered in `pkg/kubelet` often
wins and the process exits immediately. This means all other signal
handler registrations are currently racy if `DockerServer.Start()` is
directly or indirectly invoked.
This change also removes another signal handler registration from
`NewAPIServerCommand()`; a stop channel is now passed to this
function.
Lucas Käldström