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Tidy docs about EndpointSlice & related features

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Co-authored-by: Rey Lejano <52760880+reylejano@users.noreply.github.com>
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Tim Bannister
2021-04-03 16:13:50 +01:00
parent adbf10dbfe
commit c9ca131355
6 changed files with 106 additions and 105 deletions
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content/en/docs/concepts/services-networking/service-traffic-policy.md
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@@ -3,6 +3,7 @@ reviewers:
- maplain
title: Service Internal Traffic Policy
content_type: concept
weight: 45
---
@@ -19,15 +20,21 @@ cluster. This can help to reduce costs and improve performance.
## Using Service Internal Traffic Policy
You can enable Internal Traffic Policy for a Service by setting the
`spec.internalTrafficPolicy` to "Local". This tells kube-proxy to only use node
local endpoints for cluster internal traffic. Importantly, for pods on nodes with
no endpoints for a given Service, the Service will behave as if it has zero
endpoints (for Pods on this node) even if the service does have endpoints on other
nodes.
Once you have enabled the `ServiceInternalTrafficPolicy`
[feature gate](/docs/reference/command-line-tools-reference/feature-gates/),
you can enable an internal-only traffic policy for a
{{< glossary_tooltip text="Services" term_id="service" >}}, by setting its
`.spec.internalTrafficPolicy` to `Local`.
This tells kube-proxy to only use node local endpoints for cluster internal traffic.
The following example shows what a Service looks like when internalTrafficPolicy
is set to "Local":
{{< note >}}
For pods on nodes with no endpoints for a given Service, the Service
behaves as if it has zero endpoints (for Pods on this node) even if the service
does have endpoints on other nodes.
{{< /note >}}
The following example shows what a Service looks like when you set
`.spec.internalTrafficPolicy` to `Local`:
```yaml
apiVersion: v1
@@ -44,19 +51,19 @@ spec:
internalTrafficPolicy: Local
```
## How it Works
## How it works
kube-proxy filters the endpoints it routes to based on the
`spec.internalTrafficPolicy` setting. When it's "Local", only node local
endpoints are considered. When it's "Cluster" or missing, all endpoints are
The kube-proxy filters the endpoints it routes to based on the
`spec.internalTrafficPolicy` setting. When it's set to `Local`, only node local
endpoints are considered. When it's `Cluster` or missing, all endpoints are
considered.
When the feature gate `ServiceInternalTrafficPolicy` is on,
`spec.internalTrafficPolicy` defaults to "Cluster".
When the [feature gate](/docs/reference/command-line-tools-reference/feature-gates/)
`ServiceInternalTrafficPolicy` is enabled, `spec.internalTrafficPolicy` defaults to "Cluster".
## Constraints
* Service Internal Traffic Policy is not used when `externalTrafficPolicy` is set
to "Local" on a Service. It is possible to use both features in the same cluster
to `Local` on a Service. It is possible to use both features in the same cluster
on different Services, just not on the same Service.
## {{% heading "whatsnext" %}}