Fix inline markup in headers, links (#10099)
* Clean up inline markup and links - Clean up inline markup in html headers - Fix links on page and related page - Clean up some wording and add links to tutorial and concepts * Update scale-stateful-set.md
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@@ -22,7 +22,6 @@ This page shows how to delete Pods which are part of a stateful set, and explain
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{{% capture steps %}}
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## StatefulSet considerations
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In normal operation of a StatefulSet, there is **never** a need to force delete a StatefulSet Pod. The StatefulSet controller is responsible for creating, scaling and deleting members of the StatefulSet. It tries to ensure that the specified number of Pods from ordinal 0 through N-1 are alive and ready. StatefulSet ensures that, at any time, there is at most one Pod with a given identity running in a cluster. This is referred to as *at most one* semantics provided by a StatefulSet.
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@@ -79,8 +78,6 @@ Always perform force deletion of StatefulSet Pods carefully and with complete kn
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{{% capture whatsnext %}}
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Learn more about [debugging a StatefulSet](/docs/tasks/manage-stateful-set/debugging-a-statefulset/).
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Learn more about [debugging a StatefulSet](/docs/tasks/debug-application-cluster/debug-stateful-set/).
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@@ -13,29 +13,28 @@ weight: 50
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---
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{{% capture overview %}}
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This page shows how to scale a StatefulSet.
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This task shows how to scale a StatefulSet. Scaling a StatefulSet refers to increasing or decreasing the number of replicas.
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{{% /capture %}}
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{{% capture prerequisites %}}
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* StatefulSets are only available in Kubernetes version 1.5 or later.
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* **Not all stateful applications scale nicely.** You need to understand your StatefulSets well before continuing. If you're unsure, remember that it might not be safe to scale your StatefulSets.
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* You should perform scaling only when you're sure that your stateful application
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To check your version of Kubernetes, run `kubectl version`.
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* Not all stateful applications scale nicely. If you are unsure about whether to scale your StatefulSets, see [StatefulSet concepts](/docs/concepts/workloads/controllers/statefulset/) or [StatefulSet tutorial](/docs/tutorials/stateful-application/basic-stateful-set/) for futher information.
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* You should perform scaling only when you are confident that your stateful application
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cluster is completely healthy.
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{{% /capture %}}
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{{% capture steps %}}
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## Use `kubectl` to scale StatefulSets
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## Scaling StatefulSets
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Make sure you have `kubectl` upgraded to Kubernetes version 1.5 or later before
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continuing. If you're unsure, run `kubectl version` and check `Client Version`
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for which kubectl you're using.
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### Use kubectl to scale StatefulSets
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### `kubectl scale`
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First, find the StatefulSet you want to scale. Remember, you need to first understand if you can scale it or not.
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First, find the StatefulSet you want to scale.
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```shell
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kubectl get statefulsets <stateful-set-name>
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@@ -47,7 +46,7 @@ Change the number of replicas of your StatefulSet:
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kubectl scale statefulsets <stateful-set-name> --replicas=<new-replicas>
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```
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### Alternative: `kubectl apply` / `kubectl edit` / `kubectl patch`
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### Make in-place updates on your StatefulSets
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Alternatively, you can do [in-place updates](/docs/concepts/cluster-administration/manage-deployment/#in-place-updates-of-resources) on your StatefulSets.
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@@ -72,32 +71,29 @@ kubectl patch statefulsets <stateful-set-name> -p '{"spec":{"replicas":<new-repl
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## Troubleshooting
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### Scaling down doesn't work right
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### Scaling down does not work right
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You cannot scale down a StatefulSet when any of the stateful Pods it manages is unhealthy. Scaling down only takes place
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after those stateful Pods become running and ready.
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With a StatefulSet of size > 1, if there is an unhealthy Pod, there is no way
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for Kubernetes to know (yet) if it is due to a permanent fault or a transient
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one (upgrade/maintenance/node reboot). If the Pod is unhealthy due to a permanent fault, scaling
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If spec.replicas > 1, Kubernetes cannot determine the reason for an unhealthy Pod. It might be the result of a permanent fault or of a transient fault. A transient fault can be caused by a restart required by upgrading or maintenance.
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If the Pod is unhealthy due to a permanent fault, scaling
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without correcting the fault may lead to a state where the StatefulSet membership
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drops below a certain minimum number of "replicas" that are needed to function
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drops below a certain minimum number of replicas that are needed to function
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correctly. This may cause your StatefulSet to become unavailable.
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If the Pod is unhealthy due to a transient fault and the Pod might become available again,
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the transient error may interfere with your scale-up/scale-down operation. Some distributed
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the transient error may interfere with your scale-up or scale-down operation. Some distributed
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databases have issues when nodes join and leave at the same time. It is better
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to reason about scaling operations at the application level in these cases, and
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perform scaling only when you're sure that your stateful application cluster is
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perform scaling only when you are sure that your stateful application cluster is
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completely healthy.
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{{% /capture %}}
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{{% capture whatsnext %}}
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Learn more about [deleting a StatefulSet](/docs/tasks/manage-stateful-set/deleting-a-statefulset/).
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* Learn more about [deleting a StatefulSet](/docs/tasks/run-application/delete-stateful-set/).
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{{% /capture %}}
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