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Add a description to the kube-state-metrics sharding example #1091

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Jan 13, 2025
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Add a description to the kube-state-metrics sharding example #1091

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29 changes: 28 additions & 1 deletion ...s/k8s-monitoring/docs/examples/scalability/sharded-kube-state-metrics/README.md
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(NOTE: Do not edit README.md directly. It is a generated file!)
( To make changes, please modify values.yaml or description.txt and run `make examples`)
-->
# Example: scalability/sharded-kube-state-metrics/values.yaml
# Sharded kube-state-metrics

This example demonstrates how to [shard kube-state-metrics](https://github.com/kubernetes/kube-state-metrics#scaling-kube-state-metrics)
to improve scalability. This is useful when your Kubernetes cluster has a large number of objects and kube-state-metrics
is struggling to keep up. The symptoms of this might be:

* It takes longer than 60 seconds to scrape kube-state-metrics, which is longer than the scrape interval.

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MD030/list-marker-space Spaces after list markers [Expected: 3; Actual: 1]

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charts/k8s-monitoring/docs/examples/scalability/sharded-kube-state-metrics/README.md:11:1 MD030/list-marker-space Spaces after list markers [Expected: 3; Actual: 1]
* The sheer amount of metric data coming from kube-state-metrics is causing Alloy to spike its required resources.

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MD030/list-marker-space Spaces after list markers [Expected: 3; Actual: 1]

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charts/k8s-monitoring/docs/examples/scalability/sharded-kube-state-metrics/README.md:12:1 MD030/list-marker-space Spaces after list markers [Expected: 3; Actual: 1]
* kube-state-metrics itself might not be able to keep up with the number of objects in the cluster.

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MD030/list-marker-space Spaces after list markers [Expected: 3; Actual: 1]

Raw Output:
charts/k8s-monitoring/docs/examples/scalability/sharded-kube-state-metrics/README.md:13:1 MD030/list-marker-space Spaces after list markers [Expected: 3; Actual: 1]

By increasing the number of replicas and enabling [automatic sharding](https://github.com/kubernetes/kube-state-metrics#automated-sharding),
kube-state-metrics will automatically distribute the resources on the cluster across the shards.

## Changing replicas

Whenever the number of replicas changes, there are two scenarios to consider. Your requirements will dictate which one
is best for you.

### RollingUpdate

If the deployment strategy is set to `RollingUpdate`, when kube-state-metrics is updated it is possible for there to be
two running instances for a short period. This means that there shouldn't be a gap in metrics, but could lead to

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Be careful with `period`, it’s profane in some cases                                                                                 period        retext-profanities

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    26:35-26:41  warning  Be careful with `period`, it’s profane in some cases                                                                                 period        retext-profanities
duplicate metrics for a short period.

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Be careful with `period`, it’s profane in some cases                                                                                 period        retext-profanities

Raw Output:
    27:31-27:37  warning  Be careful with `period`, it’s profane in some cases                                                                                 period        retext-profanities

### Recreate

However, if the deployment strategy is set to `Recreate`, the old kube-state-metrics pod is terminated before the new
one is started. This means that there will be a gap in metrics while the new pod is starting.

## Values

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28 changes: 28 additions & 0 deletions charts/k8s-monitoring/docs/examples/scalability/sharded-kube-state-metrics/description.txt
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