[BUG] cloneset 发布的实例数与灰度比例不符

[qswksp]

What happened: 一个 cloneset 的副本数设置为 4，灰度比例设置为 50%，出现了发布 3 个实例的情况

What you expected to happen: 副本数为 4，灰度比例为 50%，期望发布 2 个实例

How to reproduce it (as minimally and precisely as possible):

1. 首先将一个 cloneset 的副本数设置为 2，以灰度比例 50% 发布新版本，此时会得到 1 个新实例 1 个旧实例
2. 删除步骤 1 中旧的那个实例
3. 删除步骤 1 中新的那个实例，然后立即将 clonset 的副本数调整为 4
4. 此时会得到 3 个新实例，1 个旧实例，与 50% 的灰度比例不符

Anything else we need to know?:

Environment:

• Kruise version: v1.1
• Kubernetes version (use kubectl version): client-go v0.20.2
• Install details (e.g. helm install args):
• Others: yaml 截图

[zmberg]

@furykerry @Perlife I know why.

1. Create cloneSet replicas=2, partition=50%
2. Update image v2, and currently there have 1 v1 pod and 1 v2 pod.
3. Delete v1 pod, and CloneSet controller will update status currentRevision=updateRevision, as follows:

status:
    availableReplicas: 1
    collisionCount: 0
    currentRevision: sample-58c8f45749
    expectedUpdatedReplicas: 1
    labelSelector: app=sample
    observedGeneration: 2
    readyReplicas: 1
    replicas: 1
    updateRevision: sample-58c8f45749
    updatedAvailableReplicas: 1
    updatedReadyReplicas: 1
    updatedReplicas: 1

4. Then scale up replicas=4, kruise will create 2 v2 pods.

Cause analysis:
The third step above is actually wrong, currentRevision and updateRevision should not be equal in the batch process. It is because of the following code judgment error:

I think it should be judged as follows:

if newStatus.UpdatedReplicas == *cs.Spec.Replicas && newStatus.UpdatedReplicas == newStatus.Replicas {
         newStatus.CurrentRevision = newStatus.UpdateRevision
}

The failed pr: #501

[qswksp]

Very clear, thank you!