mcs: watch scheduling service's primary address

[lhy1024]

What problem does this PR solve?

Issue Number: Ref #5839

What is changed and how does it work?

The API server will watch the scheduling service's primary address for redirecting HTTP requests.

Check List

Tests

• Unit test

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• JmPotato
• rleungx

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[codecov]

Codecov Report

Merging #7072 (31d5fb4) into master (2f57a9f) will increase coverage by 0.12%.
The diff coverage is 100.00%.

❗ Current head 31d5fb4 differs from pull request most recent head f20acc9. Consider uploading reports for the commit f20acc9 to get more accurate results

@@            Coverage Diff             @@
##           master    #7072      +/-   ##
==========================================
+ Coverage   74.31%   74.44%   +0.12%     
==========================================
  Files         436      436              
  Lines       46479    46484       +5     
==========================================
+ Hits        34542    34604      +62     
+ Misses       8901     8841      -60     
- Partials     3036     3039       +3     

Flag	Coverage Δ
unittests	74.44% <100.00%> (+0.12%)	⬆️

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

[rleungx]

Is it duplicated with #6976?

[lhy1024]

Is it duplicated with #6976?

oh, yes, I missed #6976, but this PR uses less code and adds a test for watching.

[lhy1024]

@JmPotato

[JmPotato]

/merge

[ti-chi-bot]

@JmPotato: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

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[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 31d5fb4

[ti-chi-bot]

@lhy1024: Your PR was out of date, I have automatically updated it for you.

If the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

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