[WIP] [minor] add rebalancer implementation

[kpango]

Signed-off-by: kpango [email protected]

Description:

implementation of rebalancer @vankichi @kevindiu @hlts2 please develop rebalancer using this base PR.

Related Issue:

How Has This Been Tested?:

Environment:

• Go Version: 1.15.2
• Docker Version: 19.03.8
• Kubernetes Version: 1.18.2
• NGT Version: 1.12.1

Types of changes:

• [ ] Bug fix [type/bug]
• [x] New feature [type/feature]
• [ ] Add tests [type/test]
• [ ] Security related changes [type/security]
• [ ] Add documents [type/documentation]
• [ ] Refactoring [type/refactoring]
• [ ] Update dependencies [type/dependency]
• [ ] Update benchmarks and performances [type/bench]
• [ ] Update CI [type/ci]

Changes to Core Features:

• [ ] Have you added an explanation of what your changes do and why you'd like us to include them?
• [ ] Have you written new tests for your core changes, as applicable?
• [ ] Have you successfully ran tests with your changes locally?

Checklist:

• [x] I have read the CONTRIBUTING document.
• [x] I have checked open Pull Requests for the similar feature or fixes?
• [ ] I have added tests and benchmarks to cover my changes.
• [ ] I have ensured all new and existing tests passed.
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have updated the documentation accordingly.

[vdaas-ci]

[WARNING:INTCFG] Changes in interal/config may require you to change Helm charts. Please check.

[vdaas-ci]

[CHATOPS:HELP] ChatOps commands.

• :ok_woman: /approve - approve
• :love_letter: /changelog - add changelog comment
• :bento: /format - format codes and add licenses
• :white_check_mark: /gen-test - generate test codes
• :label: /label - add labels
• :rewind: /rebase - rebase master

[codecov[bot]]

Codecov Report

Merging #817 (72599bc) into master (8550102) will decrease coverage by 0.21%. The diff coverage is 5.43%.

@@            Coverage Diff             @@
##           master     #817      +/-   ##
==========================================
- Coverage   28.99%   28.77%   -0.22%     
==========================================
  Files         366      369       +3     
  Lines       22013    22219     +206     
==========================================
+ Hits         6382     6394      +12     
- Misses      15324    15519     +195     
+ Partials      307      306       -1     

Impacted Files	Coverage Δ
internal/config/rebalancer.go	0.00% <0.00%> (ø)
...ernal/db/storage/blob/cloudstorage/cloudstorage.go	0.00% <0.00%> (ø)
internal/db/storage/blob/s3/option.go	84.90% <0.00%> (-15.10%)	:arrow_down:
internal/errors/k8s.go	0.00% <0.00%> (ø)
internal/errors/rebalancer.go	0.00% <0.00%> (ø)
internal/k8s/metrics/node/node.go	0.00% <0.00%> (ø)
internal/k8s/metrics/pod/pod.go	0.00% <0.00%> (ø)
internal/k8s/node/node.go	0.00% <0.00%> (ø)
internal/k8s/option.go	0.00% <0.00%> (ø)
internal/k8s/pod/pod.go	0.00% <0.00%> (ø)
... and 12 more

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[kevindiu]

/rebase

[vdaas-ci]

[REBASE] Rebase triggered by kevindiu for branch: feature/rebalancer/initial-development

[vdaas-ci]

[REBASE] Failed to rebase.