- Change the feature gate from alpha to beta and enable it by default
- Update a few of the unit tests due to feature gate being enabled by
default
- Small refactor in `nodeshutdown_manager` which adds `featureEnabled`
function (which checks that feature gate and that
`kubeletConfig.ShutdownGracePeriod > 0`).
- Use `featureEnabled()` to exit early from shutdown manager in the case
that the feature is disabled
- Update kubelet config defaulting to be explicit that
`ShutdownGracePeriod` and `ShutdownGracePeriodCriticalPods` default to
zero and update the godoc comments.
- Update defaults and add featureGate tag in api config godoc.
With this feature now in beta and the feature gate enabled by default,
to enable graceful shutdown all that will be required is to configure
`ShutdownGracePeriod` and `ShutdownGracePeriodCriticalPods` in the
kubelet config. If not configured, they will be defaulted to zero, and
graceful shutdown will effectively be disabled.
We will have two layers of the validation.
- the first part of the validation logic will be implemented under the
`ValidateKubeletConfiguration` method
- the second one that requires knowledge about machine topology and
node allocatable resources will be implemented under the memory manager.
Signed-off-by: Artyom Lukianov <alukiano@redhat.com>
Implements KEP 2000, Graceful Node Shutdown:
https://github.com/kubernetes/enhancements/tree/master/keps/sig-node/2000-graceful-node-shutdown
* Add new FeatureGate `GracefulNodeShutdown` to control
enabling/disabling the feature
* Add two new KubeletConfiguration options
* `ShutdownGracePeriod` and `ShutdownGracePeriodCriticalPods`
* Add new package, `nodeshutdown` that implements the Node shutdown
manager
* The node shutdown manager uses the systemd inhibit package, to
create an system inhibitor, monitor for node shutdown events, and
gracefully terminate pods upon a node shutdown.
The `kubelet/apis/config` package had golint failures. This change-set
removes the `kubelet/apis/config` package from the `.golint_failures`
and fixes the golint errors. In particular, this change-set adds
documentation to the public types in the package.
This change-set works towards issue#68026
CodecFactory is started with EnableStrict that throws an error when deserializing
a Kubelet component config that is malformed (e.g. unknown or duplicate keys).
When strict decoding a v1beta1 config fails, non-strict decoding is used and a warning is emitted.
For this, NewSchemeAndCodecs is now a variadic function that can take multiple
arguments for augmenting the returned codec factory. Strict decoding is
then explicitely enabled when decoding a kubelet config.
Additionally, decoding a RemoteConfigSource needs to be non-strict
to avoid an accidental error when it contains newer API fields that are not
yet known to the Kubelet.
DecodeKubeletConfiguration returns a wrapped error instead of a simple string
so its type can be tested.
Add unit tests for unhappy paths when loading a component config
Add keys for test cases struct fields, remove nil field initialization
Co-Authored-By: Jordan Liggitt <jordan@liggitt.net>
