the CloneSet pod lifecycle can be transformed to Normal only if ContainerReady is true

[chenpeicheng9]

Ⅰ. Describe what this PR does

The CloneSet pod lifecycle can be transformed to Normal only if ContainerReady is true.

Sorry for being late.
Last week After I created issue #1485, I appreciate that the Kruise team replied quickly and pointed out that it may be better "to Normal after Pod Ready" @zmberg
I've been thinking about this issue these days. I believe using the 'PodReady'(k8s.io/api/core/v1.PodReady, 'Ready' in yaml, same as below) condition may not be appropriate. Consider the scenario with the 'markPodNotReady' set: the Pod's lifecycle can only be transformed to 'Normal' if 'PodReady' is true. On the other hand, the 'PodReady' condition will be set to false at preparingDelete/preparingUpdate state. This bidirectional influence adds complexity and can make the lifecycle confusing.
So I suggest that we can use the "ContainerReady" condition, it would be simple enough.
A pod's lifecycle will be transformed from PreparingNormal to Normal only if its containers are all ready.
Furthermore, it is ok that a pod's lifecycle will be transformed to Normal only if its containers are all ready.

Ⅱ. Does this pull request fix one issue?

fixes #1485

Ⅲ. Describe how to verify it

Ⅳ. Special notes for reviews

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[kruise-bot]

Welcome @chenpeicheng9! It looks like this is your first PR to openkruise/kruise 🎉

[codecov]

Codecov Report

Attention: Patch coverage is 75.00000% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 48.54%. Comparing base (30a660b) to head (924e7a6).
Report is 52 commits behind head on master.

Files	Patch %	Lines
pkg/util/pods.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1489      +/-   ##
==========================================
+ Coverage   48.40%   48.54%   +0.13%     
==========================================
  Files         157      157              
  Lines       22440    22485      +45     
==========================================
+ Hits        10862    10915      +53     
+ Misses      10387    10364      -23     
- Partials     1191     1206      +15     

Flag	Coverage Δ
unittests	48.54% <75.00%> (+0.13%)	⬆️

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[zmberg]

For now, just consider determining if it's ready from preNormal to normal. It is not recommended to consider from update to normal.

[zmberg]

@chenpeicheng9 Can you communicate through dingding?

[chenpeicheng9]

@chenpeicheng9 Can you communicate through dingding?

sure

[furykerry]

plz squash and sign the commits

[chenpeicheng9]

As discussed, for now, I have removed the update-to-normal part. And made slight modifications to the comments. @zmberg.
Thanks, @furykerry I've squashed and signed it now.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.