koord-descheduler: support loadaware/lowNodeLoad descheduling

[eahydra]

Signed-off-by: Joseph joseph.t.lee@outlook.com

Ⅰ. Describe what this PR does

Support LoadAware descheduling. Currently support LowNodeLoad strategy.
LowNodeLoad evicts pods from overutilized nodes to underutilized nodes. Note that the plugin refers to the actual usage of the node. LowNodeLoad implements the extension point Balance. It will be called periodically.

Basic process:

1. Filter nodes according to the configured nodeSelector, and combine the configured lowThresholds and highThresholds to filter out which nodes are sourceNodes and which nodes are lowNodes(or named destinationNodes).
2. Calculate the resource capacity that can be used for migration based on the actual resource usage of the target node and the target threshold(highThresholds).
3. Filter the Pods in the sourceNodes as removablePods according to the configured evictableNamespaces and podSelectors.
4. Sort removablePods by Koordinator PriorityClass, Koordinator QoSClass, K8s QoSClass, Priority, Usage, and creation time.
5. One by one evicts each Pod and reduces the corresponding resource capacity that can be used for migration until all Pods are evicted or the available resource capacity is 0.

Ⅱ. Does this pull request fix one issue?

fix #201

Ⅲ. Describe how to verify it

Ⅳ. Special notes for reviews

V. Checklist

• I have written necessary docs and comments
• I have added necessary unit tests and integration tests
• All checks passed in make test

[eahydra]

/milestone v1.1
/hold for UT and proposal

[codecov]

Codecov Report

Base: 66.90% // Head: 67.01% // Increases project coverage by +0.11% 🎉

Coverage data is based on head (ca16b45) compared to base (c43b4db).
Patch coverage: 73.28% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #889      +/-   ##
==========================================
+ Coverage   66.90%   67.01%   +0.11%     
==========================================
  Files         234      238       +4     
  Lines       26874    27395     +521     
==========================================
+ Hits        17981    18360     +379     
- Misses       7616     7736     +120     
- Partials     1277     1299      +22     

Flag	Coverage Δ
unittests	67.01% <73.28%> (+0.11%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...ler/apis/config/validation/validation_loadaware.go	0.00% <0.00%> (ø)
...duler/framework/plugins/loadaware/low_node_load.go	64.16% <64.16%> (ø)
.../descheduler/framework/plugins/loadaware/sorter.go	69.86% <69.86%> (ø)
...er/framework/plugins/loadaware/utilization_util.go	89.47% <89.47%> (ø)
pkg/descheduler/node/node.go	85.88% <100.00%> (-0.17%)	⬇️
pkg/koordlet/runtimehooks/reconciler/reconciler.go	65.88% <0.00%> (-1.18%)	⬇️

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[eahydra]

/hold cancel
ready for review

[hormes]

/lgtm

[saintube]

/lgtm

[eahydra]

fix LowNodeLoad args error. cc @hormes @saintube

[saintube]

/lgtm

[FillZpp]

/lgtm

[koordinator-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: FillZpp

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