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4th chunk of `content/en/blog/_posts/2018-01-00-Core-Workloads-Api-Ga.md`
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The "kubernetes.io/created-by" was a legacy hold over from the days before garbage collection. Users should use an object’s ControllerRef from its ownerReferences to determine object ownership. We deprecated this feature in 1.8 and removed it in 1.9.



### Scale Subresources
A scale subresource was added to all of the applicable kinds in apps/v1beta2 (DaemonSet scales based on its node selector).  


## Kubernetes 1.9 and apps/v1
In Kubernetes 1.9, as planned, we promoted the entire core workloads API surface to GA in the apps/v1 group version. We made a few more changes to make the API consistent, but apps/v1 is mostly identical to apps/v1beta2. The reality is that most users have been treating the beta versions of the core workloads API as GA for some time now. Anyone who is still using ReplicationControllers and shying away from DaemonSets, Deployments, and StatefulSets, due to a perceived lack of stability, should plan migrate their workloads (where applicable) to apps/v1. The minor changes that were made during promotion are described below.



### Garbage Collection Defaults to Delete
Prior to apps/v1 the default garbage collection policy for Pods in a DaemonSet, Deployment, ReplicaSet, or StatefulSet, was to orphan the Pods. That is, if you deleted one of these kinds, the Pods that they owned would not be deleted automatically unless cascading deletion was explicitly specified. If you use kubectl, you probably didn’t notice this, as these kinds are scaled to zero prior to deletion. In apps/v1 all core worloads API objects will now, by default, be deleted when their owner is deleted. For most users, this change is transparent.  
Status Conditions  

Prior to apps/v1 only Deployment and ReplicaSet had Conditions in their Status objects. For consistency's sake, either all of the objects or none of them should have conditions. After some debate, we decided that Conditions are useful, and we added Conditions to StatefulSetStatus and DaemonSetStatus. The StatefulSet and DaemonSet controllers currently don’t populate them, but we may choose communicate conditions to clients, via this mechanism, in the future.

### Scale Subresource Migrated to autoscale/v1
We originally added a scale subresource to the apps group. This was the wrong direction for integration with the autoscaling, and, at some point, we would like to use custom metrics to autoscale StatefulSets. So the apps/v1 group version uses the autoscaling/v1 scale subresource.
Title: Kubernetes 1.9: apps/v1 GA Promotion and Changes
Summary
In Kubernetes 1.9, the core workloads API reached GA in apps/v1, including garbage collection defaulting to delete, the addition of Status Conditions to StatefulSetStatus and DaemonSetStatus, and the migration of the scale subresource to autoscale/v1. Users are encouraged to migrate workloads to apps/v1, especially those still using ReplicationControllers.