Add hostname policy

[ColdsteelRail]

1. Does this PR affect any open issues?(Y/N) and add issue references (e.g. "fix #123", "re #123".):

• N
• Y

2. What is the scope of this PR (e.g. component or file name):

3. Provide a description of the PR(e.g. more details, effects, motivations or doc link):

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Other

4. Are there any breaking changes?(Y/N) and describe the breaking changes(e.g. more details, motivations or doc link):

• N
• Y

5. Are there test cases for these changes?(Y/N) select and add more details, references or doc links:

• Unit test
• Integration test
• Benchmark (add benchmark stats below)
• Manual test (add detailed scripts or steps below)
• Other

6. Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 46.19%. Comparing base (b662d34) to head (47ba335).

Files with missing lines	Patch %	Lines
pkg/controllers/collaset/collaset_controller.go	75.00%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #359      +/-   ##
==========================================
+ Coverage   46.08%   46.19%   +0.11%     
==========================================
  Files         123      123              
  Lines        7660     7672      +12     
==========================================
+ Hits         3530     3544      +14     
+ Misses       3811     3808       -3     
- Partials      319      320       +1     

Flag	Coverage Δ
unittests	46.19% <75.00%> (+0.11%)	⬆️

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