I'm using the stable/memcached Helm chart (https://github.com/helm/charts/tree/master/stable/memcached)
Creating a new release works as expected. It created a StatefulSet with three pods and a Service. But when deleting the release the StatefulSet is left behind and only the Service is deleted.
helm list shows that the release is no longer there.
Is this a bug or a feature and how can I make helm delete also delete the StatefulSet?
I just did helm install stable/memcached and then deleted the release. The pods did get removed for me, which is the expected behaviour. I'm on kubernetes v1.9.7 and helm v2.10.0-rc.1+gaa98e7e. Presumably there's something preventing deletion of those resources. You could try the delete with --purge --no-hooks. There have been related bugs in previous versions so best to check your version. If it's not related to the version then best to work out if the problem is related to some nuance of the install you're doing (presumably you're running a more complex command than simply helm install stable/memcached).