# Title: What is a Kuberentes Endpoint, Anyway ?

# Authors: Pallavi Jaini, Jay Vyas, Amim Knabben

https://github.com/kubernetes/kubernetes/issues/107927 <-- interesting bug w/ endpointSlice Controller when nodes dissapear ?

# What is an Endpoint "Slice" ?

When kubernetes process the service description and if the service selector matches a pod label, kuberentes automatically creates the endpoints object with same name as service.

Taking a look at a fresh cluster, you might notice that there are both endpoints, and endpoint slices for your services:

~  kubectl get services -A
NAMESPACE     NAME         TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)                  AGE
default       kubernetes   ClusterIP   10.96.0.1      <none>        443/TCP                  9h
kube-system   antrea       ClusterIP   10.96.40.142   <none>        443/TCP                  9h
kube-system   kube-dns     ClusterIP   10.96.0.10     <none>        53/UDP,53/TCP,9153/TCP   9h

~  kubectl get endpoints -A
NAMESPACE            NAME                    ENDPOINTS                                            AGE
default              kubernetes              172.19.0.7:6443                                      9h
kube-system          antrea                  172.19.0.5:10349                                     9h
kube-system          kube-dns                10.10.0.2:53,10.10.0.3:53,10.10.0.2:53 + 3 more...   9h

The same services have corresponding...

-> % kubectl get endpointslices -A
NAMESPACE     NAME             ADDRESSTYPE   PORTS        ENDPOINTS             AGE
default       kubernetes       IPv4          6443         172.18.0.2            2m35s
kube-system   antrea-gllz8     IPv4          10349        172.18.0.3            78s
kube-system   kube-dns-sfk96   IPv4          9153,53,53   10.10.0.2,10.10.0.3   2m19s

When do endpointSlices get made? (look at maxEpPerSlice, will that result in more epslices???)

The control plane automatically creates EndpointSlices for any Kubernetes Service that has a selector specified.

How can we configure it?

Why would we configure it ?

## History

# what happens when an endpoint is created?

- Sequence diagram
- ...

# What is the difference between and endpoint and a pod

...

# how do endpointSlice controllers work ?

# how does the kube-proxy deal w/ endpoints and endpointSlices?

# how does KPNG deal w/ endpoints, endpointSlices?

# how do Nodes respond to changing endpoints in a cluster

# What about CNI providers ?

## NetworkPolicies ?
...
## CNI based proxying
...