[Sample] Cross node preemption plugin #56
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[APPROVALNOTIFIER] This PR is APPROVED This pull-request has been approved by: Huang-Wei The full list of commands accepted by this bot can be found here. The pull request process is described here
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| @@ -50,7 +50,7 @@ update-vendor: | |||
| hack/update-vendor.sh | |||
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| .PHONY: unit-test | |||
| unit-test: update-vendor | |||
| unit-test: autogen | |||
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This is now needed as the testing in crossnodepreemption now needs the open API stuff to be fully generated. Otherwise, the test fails:
? sigs.k8s.io/scheduler-plugins/pkg/apis/config/scheme [no test files]
? sigs.k8s.io/scheduler-plugins/pkg/apis/config/v1beta1 [no test files]
ok sigs.k8s.io/scheduler-plugins/pkg/coscheduling 0.756s
# k8s.io/kubernetes/cmd/kube-apiserver/app
vendor/k8s.io/kubernetes/cmd/kube-apiserver/app/server.go:467:70: undefined: "k8s.io/kubernetes/pkg/generated/openapi".GetOpenAPIDefinitions
FAIL sigs.k8s.io/scheduler-plugins/pkg/crossnodepreemption [build failed]
ok sigs.k8s.io/scheduler-plugins/pkg/noderesources 0.187s
ok sigs.k8s.io/scheduler-plugins/pkg/qos 0.150s
FAIL
make: *** [Makefile:54: unit-test] Error 2
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/cc @denkensk |
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| func (s *candidate) Victims() *extenderv1.Victims { | ||
| return &extenderv1.Victims{ | ||
| Pods: s.victims, | ||
| NumPDBViolations: 0, |
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Why we add the field NumPDBViolations here other than use the struct *extenderv1.Victims like defaultPreempt?
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The intention is to make candidate irrelevant with the extenderv1 pkg, so that in the preemption logic, we don't need to worry about extenderv1 pkg. And returning extenderv1.Victims here does nothing magic but ensuring it adheres to Candidate interface.
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| // nodesWherePreemptionMightHelp returns a list of nodes with failed predicates | ||
| // that may be satisfied by removing pods from the node. | ||
| func nodesWherePreemptionMightHelp(nodes []*framework.NodeInfo, m framework.NodeToStatusMap) []*framework.NodeInfo { |
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I also use this function in capacityScheduling.go. Make it public in defaultPreempt?
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Thanks |
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The PostFilter extension point was introduced in Kubernetes Scheduler since 1.19,
and the default implementation in upstream is to preempt Pods on the same node
to make room for the unschedulable Pod.
In contrast to the "same-node-preemption" strategy, we can come up with a "cross-node-preemption"
strategy to preempt Pods across multiple nodes, which is useful when a Pod cannot be
scheduled due to "cross node" constraints such as PodTopologySpread and PodAntiAffinity.
This was also mentioned in the original design document of Preemption.
This plugin is built as a sample to demonstrate how to use PostFilter extension point,
as well as inspiring users to built their own innovative strategies, such as preepmpting
a group of Pods.