Enabling EndpointSlices

This page provides an overview of enabling EndpointSlices in Kubernetes.

Before you begin

You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:

• Katacoda
• Play with Kubernetes

Introduction

EndpointSlices provide a scalable and extensible alternative to Endpoints in Kubernetes. They build on top of the base of functionality provided by Endpoints and extend that in a scalable way. When Services have a large number (>100) of network endpoints, they will be split into multiple smaller EndpointSlice resources instead of a single large Endpoints resource.

Enabling EndpointSlices

Note: Although EndpointSlices may eventually replace Endpoints, many Kubernetes components still rely on Endpoints. For now, enabling EndpointSlices should be seen as an addition to Endpoints in a cluster, not a replacement for them.

EndpointSlice functionality in Kubernetes is made up of several different components, most are enabled by default:

• The EndpointSlice API: EndpointSlices are part of the discovery.k8s.io/v1beta1 API. This is beta and enabled by default since Kubernetes 1.17. All components listed below are dependent on this API being enabled.
• The EndpointSlice Controller: This controller maintains EndpointSlices for Services and the Pods they reference. This is controlled by the EndpointSlice feature gate. It has been enabled by default since Kubernetes 1.18.
• The EndpointSliceMirroring Controller: This controller mirrors custom Endpoints to EndpointSlices. This is controlled by the EndpointSlice feature gate. It has been enabled by default since Kubernetes 1.19.
• Kube-Proxy: When kube-proxy is configured to use EndpointSlices, it can support higher numbers of Service endpoints. This is controlled by the EndpointSliceProxying feature gate on Linux and WindowsEndpointSliceProxying on Windows. It has been enabled by default on Linux since Kubernetes 1.19. It is not enabled by default for Windows nodes. To configure kube-proxy to use EndpointSlices on Windows, you can enable the WindowsEndpointSliceProxying feature gate on kube-proxy.

Using EndpointSlices

With EndpointSlices fully enabled in your cluster, you should see corresponding EndpointSlice resources for each Endpoints resource. In addition to supporting existing Endpoints functionality, EndpointSlices include new bits of information such as topology. They will allow for greater scalability and extensibility of network endpoints in your cluster.

What's next

• Read about EndpointSlices
• Read Connecting Applications with Services