This was an oversight in the initial EndpointSlice release. This update
will ensure that Endpoints and EndpointSlices use the same logic to set
the Hostname attribute.
The Service spec includes a PublishNotReadyAddresses field which has
been used by Endpoints to report all matching resources ready. This may
or may not have been the initial purpose of the field, but given the
desire to provide backwards compatibility with the Endpoints API here,
it seems to make sense to continue to provide the same functionality.
This should fix a bug that could break masters when the EndpointSlice
feature gate was enabled. This was all tied to how the apiserver creates
and manages it's own services and endpoints (or in this case endpoint
slices). Consumers of endpoint slices also need to know about the
corresponding service. Previously we were trying to set an owner
reference here for this purpose, but that came with potential downsides
and increased complexity. This commit changes behavior of the apiserver
endpointslice integration to set the service name label instead of owner
references, and simplifies consumer logic to reference that (both are
set by the EndpointSlice controller).
Additionally, this should fix a bug with the EndpointSlice GenerateName
value that had previously been set with a "." as a suffix.
