feat: update PodDecoration API design

[Eikykun]

1. Does this PR affect any open issues?(Y/N) and add issue references:

• N
• Y

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

PodDecoration Proposal

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. Release note

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

None

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Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (412b4f2) 46.17% compared to head (3ad33e4) 59.58%.
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Additional details and impacted files

@@             Coverage Diff             @@
##             main     #122       +/-   ##
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+ Coverage   46.17%   59.58%   +13.40%     
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  Files          45       46        +1     
  Lines        3558     3489       -69     
===========================================
+ Hits         1643     2079      +436     
+ Misses       1700     1190      -510     
- Partials      215      220        +5     

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[Eikykun]

Oth proposal,

1. Should PD select pods by collaset? such as

  selector:               # Select the Pods to inject config.
    matchCollaSet:
    - collaSet-a
    - collaSet-b
    matchLabels:          # Select a group of Pods by labelSelector.
      ...
    matchExpressions:     # Or select specific Pods by matchExpressions.
      ...

2. Support RollingUpdate by CollaSet partition?

  updateStrategy:
    rollingUpdate: 
      collaSet:
      - name: collaSet-a
         partition: 2 

cc @wu8685 @zoumo @shaofan-hs

[wu8685]

It would be better to use All as the default value. There usually is only one primary container.

[wu8685]

Oth proposal,

1. Should PD select pods by collaset? such as

  selector:               # Select the Pods to inject config.
    matchCollaSet:
    - collaSet-a
    - collaSet-b
    matchLabels:          # Select a group of Pods by labelSelector.
      ...
    matchExpressions:     # Or select specific Pods by matchExpressions.
      ...

2. Support RollingUpdate by CollaSet partition?

  updateStrategy:
    rollingUpdate: 
      collaSet:
      - name: collaSet-a
         partition: 2 

cc @wu8685 @zoumo @shaofan-hs

I think PD users need not to provide the CollaSet name. Telling PD which pods to inject could be enough.

About the item 2, I can't get your meaning. Why does PD need to know the CollaSet partition?

[Eikykun]

I think PD users need not to provide the CollaSet name. Telling PD which pods to inject could be enough.

About the item 2, I can't get your meaning. Why does PD need to know the CollaSet partition?

If PD selects Pods under multiple CollaSet, can I still use updateStrategy.rollingUpdate.partition to control the upgrade?
If so, how do I decide the pods under multiple CollaSets corresponding to the partition?

[wu8685]

I think PD users need not to provide the CollaSet name. Telling PD which pods to inject could be enough.
About the item 2, I can't get your meaning. Why does PD need to know the CollaSet partition?

If PD selects Pods under multiple CollaSet, can I still use updateStrategy.rollingUpdate.partition to control the upgrade? If so, how do I decide the pods under multiple CollaSets corresponding to the partition?

How about sharing the same data between CollaSet and PD controller? PD controller decides the Pod partition, and store this info into the shared memory. Then CollaSet controller is able to know the Pod partition info under each CollaSet from the shared memory.

Take the reference from this part of the doc

cons: CollaSet controller can not run separately from PD controller

[wu8685]

lgtm