StatefulSet Status Conditions Field Not Populating

General Discussions
1

Description of the issue
The conditions field in the status of a StatefulSet is not getting populated. However, when using a Deployment, the conditions field is populated as expected.

Kubernetes Version
1.30.5

To Reproduce
Steps to reproduce the behavior:

  1. Create a StatefulSet using the following Sample YAML:
    apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: nginx-statefulset
  namespace: default
spec:
  serviceName: "nginx-service"
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        ports:
        - containerPort: 80
          name: http
        resources:
          requests:
            cpu: "100m"
            memory: "128Mi"
          limits:
            cpu: "200m"
            memory: "256Mi"
  volumeClaimTemplates:
  - metadata:
      name: nginx-storage
    spec:
      accessModes: ["ReadWriteOnce"]
      resources:
        requests:
          storage: 1Gi
  2. Deploy the StatefulSet using:
    kubectl apply -f <filename>.yaml
  3. Check the StatefulSet status using:
    kubectl get statefulset nginx-statefulset -n default -o yaml

Expected behavior
The conditions field in the status of the StatefulSet should be populated similarly to how it is populated for a Deployment.

StatefulSet Status Details:

status:
  availableReplicas: 0
  collisionCount: 0
  currentRevision: nginx-statefulset-5b966b65c7
  observedGeneration: 3
  replicas: 1
  updateRevision: nginx-statefulset-5f5c9b5765
  updatedReplicas: 1

Deployment Status Details:

status:
  availableReplicas: 3
  conditions:
  - lastTransitionTime: "2024-10-22T15:44:33Z"
    lastUpdateTime: "2024-10-22T15:44:33Z"
    message: Deployment has minimum availability.
    reason: MinimumReplicasAvailable
    status: "True"
    type: Available
  - lastTransitionTime: "2024-10-22T15:44:31Z"
    lastUpdateTime: "2024-10-22T15:44:33Z"
    message: ReplicaSet "nginx-deployment-5c45cbfff4" has successfully progressed.
    reason: NewReplicaSetAvailable
    status: "True"
    type: Progressing
  observedGeneration: 1
  readyReplicas: 3
  replicas: 3
  updatedReplicas: 3
2

Its not missing but the way statefulset works is different than deployment. It do not track or maintain detail rollout conditions similar to deployment type.

In my opinion its not a bug but more of a design decision. The lack of a populated conditions field for StatefulSets is consistent with how Kubernetes prioritizes StatefulSet stability without adding extra rollout condition monitoring.

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