Rob Scott
100 lines
3.0 KiB
Markdown
100 lines
3.0 KiB
Markdown
---
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reviewers:
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- freehan
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title: Endpoint Slices
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feature:
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title: Endpoint Slices
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description: >
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Scalable tracking of network endpoints in a Kubernetes cluster.
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content_template: templates/concept
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weight: 10
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---
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{{% capture overview %}}
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{{< feature-state for_k8s_version="v1.17" state="beta" >}}
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_Endpoint Slices_ provide a simple way to track network endpoints within a
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Kubernetes cluster. They offer a more scalable and extensible alternative to
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Endpoints.
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{{% /capture %}}
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{{% capture body %}}
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## Endpoint Slice resources {#endpointslice-resource}
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In Kubernetes, an EndpointSlice contains references to a set of network
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endpoints. The EndpointSlice controller automatically creates Endpoint Slices
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for a Kubernetes Service when a selector is specified. These Endpoint Slices
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will include references to any Pods that match the Service selector. Endpoint
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Slices group network endpoints together by unique Service and Port combinations.
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As an example, here's a sample EndpointSlice resource for the `example`
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Kubernetes Service.
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```yaml
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apiVersion: discovery.k8s.io/v1beta1
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kind: EndpointSlice
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metadata:
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name: example-abc
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labels:
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kubernetes.io/service-name: example
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addressType: IPv4
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ports:
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- name: http
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protocol: TCP
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port: 80
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endpoints:
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- addresses:
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- "10.1.2.3"
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conditions:
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ready: true
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hostname: pod-1
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topology:
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kubernetes.io/hostname: node-1
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topology.kubernetes.io/zone: us-west2-a
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```
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By default, Endpoint Slices managed by the EndpointSlice controller will have no
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more than 100 endpoints each. Below this scale, Endpoint Slices should map 1:1
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with Endpoints and Services and have similar performance.
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Endpoint Slices can act as the source of truth for kube-proxy when it comes to
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how to route internal traffic. When enabled, they should provide a performance
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improvement for services with large numbers of endpoints.
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## Address Types
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EndpointSlices support three address types:
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* IPv4
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* IPv6
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* FQDN (Fully Qualified Domain Name)
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## Motivation
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The Endpoints API has provided a simple and straightforward way of
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tracking network endpoints in Kubernetes. Unfortunately as Kubernetes clusters
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and Services have gotten larger, limitations of that API became more visible.
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Most notably, those included challenges with scaling to larger numbers of
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network endpoints.
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Since all network endpoints for a Service were stored in a single Endpoints
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resource, those resources could get quite large. That affected the performance
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of Kubernetes components (notably the master control plane) and resulted in
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significant amounts of network traffic and processing when Endpoints changed.
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Endpoint Slices help you mitigate those issues as well as provide an extensible
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platform for additional features such as topological routing.
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{{% /capture %}}
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{{% capture whatsnext %}}
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* [Enabling Endpoint Slices](/docs/tasks/administer-cluster/enabling-endpoint-slices)
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* Read [Connecting Applications with Services](/docs/concepts/services-networking/connect-applications-service/)
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{{% /capture %}}
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