* Move ClusterEvent type to staging repo, leaving some functions (that contain logic internal to scheduler) in kubernetes/kubernetes
apply review comment and fix linter warning
* update-vendor.sh
* update doc comments
* run update-vendor.sh
The current behavior is to select only based on pod priority, where any
pod with higher priority can preempt any pod with lower priority.
In our case, we have multiple priority classes but where only a subset
of those are considered preemptible. Here's roughly how this looks:
- High priority: higher in the scheduling queue, not preemptible
- Low priority: lower in the scheduling queue, not preemptible
- Preemptible priority: lowest in the scheduling queue, preemptible
This PR allows the preemption selection to be configured against the
`DefaultPreemption` plugin, rather than needing to reimplement the
plugin itself. The structure used here mimics [what's currently being
done for the `Evaluator`](https://github.com/kubernetes/kubernetes/blob/release-1.32/pkg/scheduler/framework/preemption/preemption.go#L161-L165),
where a `PreemptPod` callback may be overridden to customize what
happens when performing a preemption.
This PR also updates the plugin's tests to call the updated `New()`
function rather than constructing `DefaultPreemption` directly, so
that `New()` is now being exercised in tests.
Currently, the NodeResourcesFit plugin always returns Unschedulable when a pod's
resource requests exceed a node's available resources. However, when a pod's
requests exceed the node's total allocatable, preemption cannot help since even
an empty node would not have enough resources.
This change modifies the NodeResourcesFit plugin to return UnschedulableAndUnresolvable
when a pod's resource requests exceed the node's total allocatable. This helps
optimize the scheduling process in large clusters by:
1. Reducing the number of candidate nodes that need to be considered for preemption
2. Providing clearer feedback about unresolvable resource constraints
3. Improving scheduling performance by avoiding unnecessary preemption calculations
The change is particularly beneficial in heterogeneous clusters where node sizes
vary significantly, as it helps quickly identify nodes that are fundamentally
too small for certain pods.
Fixes https://github.com/kubernetes/kubernetes/issues/131310
Co-authored-by: Kensei Nakada <handbomusic@gmail.com>
When preemption finds no candidates, it currently makes an explicit API
call to clear the pod's nominatedNodeName in findCandidates(). However,
this is redundant because:
1. When no candidates are found, Preempt() returns a PostFilterResult with
an empty nominatedNodeName via NewPostFilterResultWithNominatedNode("")
2. This empty nominatedNodeName is propagated through the scheduling
cycle to handleSchedulingFailure()
3. handleSchedulingFailure() then properly clears the nominatedNodeName
through updatePod()
Remove the explicit ClearNominatedNodeName call in findCandidates() to
reduce unnecessary API calls while maintaining the same behavior.
This change improves performance by eliminating a duplicate API call
without changing the functional behavior of preemption.
