Add federatedHpa controller

[Poor12]

What type of PR is this? /kind feature

What this PR does / why we need it: Part of https://github.com/karmada-io/karmada/issues/3379 This PR focus on centralizedHpa controller, the responsibility is:

1. Get metrics and pods across multiple clusters and calculate desired replicas
2. Scale resource template based on desiredReplicas

Which issue(s) this PR fixes: Fixes #

Special notes for your reviewer:

1. Need a Centralized API Definition.
2. Need to clarify the behavior of Duplicated. When users use duplicated policy to propagate resource templates to multiple clusters, the min/max of hpa means whether the all replicas across clusters or in the single cluster.
3. Ignore Lint because we want to keep the same between the upstream and centralizedHpa controller.

Does this PR introduce a user-facing change?: None

[chaunceyjiang]

Ignore Lint

What's mean? golang-lint ?

[Poor12]

Ignore Lint

What's mean? golang-lint ?

Yeah, centralizedHpa controller use part of codes in the native K8s hpa-controller. We do not want to change them right now even if it will not pass golang-lint.

[Poor12]

/cc @chaunceyjiang @XiShanYongYe-Chang @RainbowMango

[chaunceyjiang]

Yeah, centralizedHpa controller use part of codes in the native K8s hpa-controller. We do not want to change them right now even if it will not pass golang-lint.

🤔

So, in the future, all PRs will not be able to pass the golang-lint check, right?

[Poor12]

Yeah, centralizedHpa controller use part of codes in the native K8s hpa-controller. We do not want to change them right now even if it will not pass golang-lint.

🤔

So, in the future, all PRs will not be able to pass the golang-lint check, right?

Not exactly, for those long function which is lifted from kubernetes, now we just keep the same. For others, we will deal with the golang-lint.

[codecov-commenter]

Codecov Report

Merging #3589 (3a14648) into master (1e7ab93) will increase coverage by 0.00%. The diff coverage is 56.92%.

:exclamation: Your organization is not using the GitHub App Integration. As a result you may experience degraded service beginning May 15th. Please install the Github App Integration for your organization. Read more.

@@           Coverage Diff            @@
##           master    #3589    +/-   ##
========================================
  Coverage   55.83%   55.84%            
========================================
  Files         216      220     +4     
  Lines       20129    20595   +466     
========================================
+ Hits        11240    11501   +261     
- Misses       8284     8484   +200     
- Partials      605      610     +5     

Flag	Coverage Δ
unittests	55.84% <56.92%> (+<0.01%)	:arrow_up:

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

Impacted Files	Coverage Δ
cmd/controller-manager/app/options/options.go	0.00% <0.00%> (ø)
pkg/controllers/context/context.go	48.57% <ø> (ø)
pkg/controllers/federatedhpa/metrics/client.go	0.00% <0.00%> (ø)
pkg/util/helper/pod.go	92.00% <0.00%> (-8.00%)	:arrow_down:
pkg/util/membercluster_client.go	60.16% <0.00%> (-12.39%)	:arrow_down:
pkg/util/lifted/federatedhpa.go	36.95% <36.95%> (ø)
pkg/util/lifted/selectors/bimultimap.go	88.98% <88.98%> (ø)
...kg/controllers/federatedhpa/metrics/utilization.go	100.00% <100.00%> (ø)
...armadactl/cmdinit/karmada/webhook_configuration.go	86.12% <100.00%> (+0.84%)	:arrow_up:
pkg/util/fedinformer/transform.go	79.16% <100.00%> (+1.89%)	:arrow_up:

... and 1 file with indirect coverage changes

[Poor12]

Codebase is ready now. For some lifted code, I store it in the pkg/ right now. Later I will move it to lifted for better management.

[RainbowMango]

lint is failing:

pkg/util/helper/federatedhpa_test.go:5: File is not `gci`-ed with --skip-generated -s Standard,Default,Prefix(github.com/karmada-io/karmada) (gci)
    "github.com/stretchr/testify/assert"
pkg/util/helper/federatedhpa_test.go:6: File is not `gci`-ed with --skip-generated -s Standard,Default,Prefix(github.com/karmada-io/karmada) (gci)

pkg/util/helper/federatedhpa_test.go:4: File is not `gofmt`-ed with `-s` (gofmt)
    "testing"

[Poor12]

/cc @jwcesign @RainbowMango

[karmada-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: RainbowMango

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/karmada-io/karmada/blob/master/OWNERS)~~ [RainbowMango] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment