> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Endpoints and Endpoint Slices Overview

> This guide explains how Endpoints and Endpoint Slices work in Kubernetes, their roles in traffic routing, and how to inspect them.

Kubernetes Services provide a stable network endpoint for Pods, but under the hood, Services rely on two resources—**Endpoints** and **Endpoint Slices**—to map Service selectors to Pod IPs and ports. This guide explains how each resource works, their roles in traffic routing, and how to inspect them.

## Endpoints

An **Endpoint** object in Kubernetes keeps track of all Pod IPs and ports that back a Service. When you create a Service, Kubernetes uses its label selector to identify matching Pods and generates an Endpoints object with the same name.

<Frame>
  ![The image illustrates a network diagram showing a service (SVC) connected to endpoints with specific IP addresses, which in turn connect to three different pods.](https://kodekloud.com/kk-media/image/upload/v1752880346/notes-assets/images/Kubernetes-Networking-Deep-Dive-Endpoints-and-Endpoint-Slices-Overview/network-diagram-service-endpoints-pods.jpg)
</Frame>

As Pods are created, deleted, or updated, the Endpoints object is managed automatically by the control plane—no manual edits are needed.

### Inspecting an Endpoints Object

Use `kubectl` to view the Endpoints backing a Service:

```bash theme={null}
kubectl get endpoints SERVICE_NAME -o yaml
```

Example output:

```yaml theme={null}
subsets:
- addresses:
  - ip: 10.244.1.172
    nodeName: node
    targetRef:
      kind: Pod
      name: pod-name-5f68f556c8-25nb9
      namespace: default
  ports:
  - name: HTTP
    port: 80
    protocol: TCP
```

Fields explained:

* `subsets`: Groups of addresses and ports.
* `addresses`: Lists Pod IPs and node names.
* `ports`: Indicates which port names and protocols are exposed.

### Limitations of Endpoints

<Callout icon="triangle-alert" color="#FF6B6B">
  Each Endpoints object can hold up to **1,000 addresses**. In large clusters or high-scale environments, this cap may lead to performance bottlenecks or truncated endpoint lists.
</Callout>

| Resource  | Maximum Addresses | Impact                                  |
| --------- | ----------------- | --------------------------------------- |
| Endpoints | 1,000             | May require Service sharding or slicing |

<Frame>
  ![The image is a slide titled "Endpoint – Limitations," indicating that Kubernetes restricts endpoints to 1,000.](https://kodekloud.com/kk-media/image/upload/v1752880347/notes-assets/images/Kubernetes-Networking-Deep-Dive-Endpoints-and-Endpoint-Slices-Overview/endpoint-limitations-kubernetes-restrictions.jpg)
</Frame>

## Endpoint Slices

Introduced as a beta feature in v1.17 and GA in v1.21, **Endpoint Slices** solve the scalability issues of Endpoints by splitting Pod endpoints into multiple, smaller objects. Each slice holds a subset of IPs, ports, and metadata, reducing control-plane load.

<Frame>
  ![The image is a diagram titled "Endpoint Slices," illustrating an advanced, scalable way to manage a network, with a network icon and a gradient label.](https://kodekloud.com/kk-media/image/upload/v1752880348/notes-assets/images/Kubernetes-Networking-Deep-Dive-Endpoints-and-Endpoint-Slices-Overview/endpoint-slices-network-diagram.jpg)
</Frame>

<Callout icon="lightbulb" color="#1CB2FE">
  Endpoint Slices support optional fields like **topology hints**, enabling you to optimize traffic routing based on node labels or zones.
</Callout>

### How Endpoint Slices Work

<Frame>
  ![The image illustrates how Endpoint Slices work in Kubernetes, showing the relationship between services, endpoint slices, and pods, with notes on management and dynamic updates.](https://kodekloud.com/kk-media/image/upload/v1752880349/notes-assets/images/Kubernetes-Networking-Deep-Dive-Endpoints-and-Endpoint-Slices-Overview/kubernetes-endpoint-slices-illustration.jpg)
</Frame>

* **Slices per Service**: Multiple Endpoint Slice objects can coexist for one Service.
* **Subset Size**: By default, each slice holds up to 100 endpoints, configurable via the EndpointSlice API.
* **Automatic Updates**: The control plane synchronizes slices as Pods change state.

#### Viewing Endpoint Slices

```bash theme={null}
kubectl get endpointslices SERVICE_NAME-UID -o yaml
```

Sample YAML:

```yaml theme={null}
endpoints:
- addresses:
  - 10.244.1.172
  conditions:
    ready: true
    serving: true
    terminating: false
  nodeName: worker
  targetRef:
    kind: Pod
    name: pod-name-5f68f556c8-25nb9
    namespace: default
    uid: e77f4587-6d20-48bb-b5f6-f6df51a886d
  ports:
  - name: http
    port: 80
    protocol: TCP
```

| Feature             | Endpoints  | Endpoint Slices                                        |
| ------------------- | ---------- | ------------------------------------------------------ |
| Scalability         | ≤1,000 IPs | Configurable slice size, multiple slices per Service   |
| Metadata & Topology | Limited    | Supports zone hints, custom labels                     |
| Control-Plane Load  | Higher     | Distributed across slices, fewer large updates overall |

## References

* [Kubernetes Endpoints Documentation](https://kubernetes.io/docs/concepts/services-networking/service/#endpoints)
* [Endpoint Slices Documentation](https://kubernetes.io/docs/concepts/services-networking/endpoint-slices/)
* [kubectl Cheat Sheet](https://kubernetes.io/docs/reference/kubectl/cheatsheet/)
* [Kubernetes Networking Deep Dive](https://kubernetes.io/blog/2020/09/03/kubernetes-networking-deep-dive/)

<CardGroup>
  <Card title="Watch Video" icon="video" cta="Learn more" href="https://learn.kodekloud.com/user/courses/kubernetes-networking/module/00c6db37-72b0-44e1-8c3a-81e22c8d8af6/lesson/80501a3d-5b9b-46fc-b0f3-21c376a1730f" />
</CardGroup>