Hands-On Microservices with Kubernetes

When should you use a StatefulSet?

You should use a StatefulSet when you manage your data store yourself in the cloud and require good control over the storage your data store uses. The primary use case is for distributed data stores, but a StatefulSet is useful even if your data store has just one instance or pod. The stable pod identity with the stable attached storage is well worth it, although orderliness, of course, is not required. If your data store is backed up by a shared storage layer such as NFS, then a StatefulSet might not be necessary.

Additionally, this may be common sense, but if you don't manage the data store yourself, then you don't need to worry about the storage layer and you don't need to define your own StatefulSets. ...