Add documentation for Scheduler performance tuning #10048

bsalamat · 2018-08-22T18:57:50Z

/sig scheduling
/ref kubernetes/enhancements/issues/593
/ref kubernetes/kubernetes/issues/66627

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bsalamat · 2018-09-06T18:10:34Z

/assign @ravisantoshgudimetla

Hi Ravi,
could you please help us review this PR?

ravisantoshgudimetla · 2018-09-07T20:17:55Z

content/en/docs/concepts/configuration/scheduler-perf-tuning.md

+
+{{< feature-state for_k8s_version="1.12" >}}
+
+Kube-scheduler is the Kubernetes default scheduler. It is responsible for


Do we need this statement?

It is in the overview section. It would be helpful for someone unfamiliar with the topic to know what they are reading about.

ravisantoshgudimetla · 2018-09-07T20:18:57Z

content/en/docs/concepts/configuration/scheduler-perf-tuning.md

+Kube-scheduler is the Kubernetes default scheduler. It is responsible for
+placement of Pods on proper Nodes of a cluster. Nodes of a cluster that meet the
+scheduling requirements of a Pod are called feasible Nodes for the Pod. The
+scheduler find feasible Nodes for a Pod and then runs a set of functions to


nit: s/find/finds

ravisantoshgudimetla · 2018-09-07T20:19:41Z

content/en/docs/concepts/configuration/scheduler-perf-tuning.md

+{{% capture overview %}}
+
+{{< feature-state for_k8s_version="1.12" >}}
+


Or probably, name this paragraph as background.

It is in the overview section. In all of our documents the first section serves as the overview/background.

bsalamat

Thanks, @ravisantoshgudimetla!

bsalamat · 2018-09-07T20:23:39Z

content/en/docs/concepts/configuration/scheduler-perf-tuning.md

+{{% capture overview %}}
+
+{{< feature-state for_k8s_version="1.12" >}}
+


It is in the overview section. In all of our documents the first section serves as the overview/background.

bsalamat · 2018-09-07T20:24:40Z

content/en/docs/concepts/configuration/scheduler-perf-tuning.md

+
+{{< feature-state for_k8s_version="1.12" >}}
+
+Kube-scheduler is the Kubernetes default scheduler. It is responsible for


It is in the overview section. It would be helpful for someone unfamiliar with the topic to know what they are reading about.

bsalamat · 2018-09-07T20:27:32Z

content/en/docs/concepts/configuration/scheduler-perf-tuning.md

+Kube-scheduler is the Kubernetes default scheduler. It is responsible for
+placement of Pods on proper Nodes of a cluster. Nodes of a cluster that meet the
+scheduling requirements of a Pod are called feasible Nodes for the Pod. The
+scheduler find feasible Nodes for a Pod and then runs a set of functions to


ravisantoshgudimetla · 2018-09-07T20:30:52Z

content/en/docs/concepts/configuration/scheduler-perf-tuning.md

+score a higher value for running the given Pod might not even be passed to the
+scoring phase. This would result in a less than ideal placement of the Pod. For
+this reason, the value should not be set to very low percentages. A general rule
+of thumb is to never set the value to anything lower than 30. Lower values


Lower than 30 in any cluster?

Yes, this is percentage. So, general rule of thumb is not to set this value below 30% unless you know what you are doing.

ravisantoshgudimetla

@bsalamat Mostly LGTM except for nits.

ravisantoshgudimetla · 2018-09-07T20:34:24Z

content/en/docs/concepts/configuration/scheduler-perf-tuning.md

+scheduler continues from the point in the array that it stopped when checking
+feasibility of the previous Pod.
+
+If Nodes are in multiple zones, the scheduler iterates over Nodes in various


Probably, we can mention the side-effect of having unequal number of nodes in zones causing unequal spread.

unequal number of nodes in zones shouldn't be a problem. It of course causes more pods to be scheduled in zones with larger number of zones, but that's expected and not different than before.

zparnold · 2018-09-10T02:43:15Z

@bsalamat @ravisantoshgudimetla Is this doc in a "technical" shape (i.e. ready for my review from a english/grammar perspective?) I'd like to get this merged this week ideally. 😄

xiangpengzhao · 2018-09-07T00:56:34Z

content/en/docs/concepts/configuration/scheduler-perf-tuning.md

+
+{{% capture overview %}}
+
+{{< feature-state for_k8s_version="1.12" >}}


Shouldn't we show its version state here ? e.g. :
{{< feature-state for_k8s_version="v1.12" state="alpha" >}}

This does not include an API change. It is a performance improvement shipped with 1.12. So, the backward compatibility and its associated guarantees that exist with alpha, beta, GA features do not apply to this one.

xiangpengzhao · 2018-09-07T00:58:08Z

content/en/docs/concepts/configuration/scheduler-perf-tuning.md

+
+{{% capture body %}}
+
+## Percentage of Nodes To Score


xiangpengzhao · 2018-09-07T01:02:15Z

content/en/docs/concepts/configuration/scheduler-perf-tuning.md

+scheduler still checks all the nodes, simply because there are not enough
+feasible nodes to stop the scheduler's search early. {{< /note >}}
+
+**To disable this feature**, you can set `percentageOfNodesToScore` to 100.


Is there a feature gate for this feature?

There is no feature gate, but as is mentioned in the doc, it can be practically disabled by setting the percentage to 100.

ravisantoshgudimetla

/lgtm

Thanks @bsalamat for the PR. The PR LGTM

ravisantoshgudimetla · 2018-09-10T13:47:22Z

Is this doc in a "technical" shape (i.e. ready for my review from a english/grammar perspective?) I'd like to get this merged this week ideally. smile

@zparnold - This looks good to me from technical perspective. Thanks

justaugustus · 2018-09-11T09:33:30Z

@bsalamat -- what's the status here? Docs are overdue at this point and we need to merge ASAP.
@ravisantoshgudimetla -- if this still looks good from the technical, please re-/lgtm when you have a chance.

bsalamat · 2018-09-11T17:35:56Z

The PR is ready. I asked Ravi on Slack to re-lgtm it.

ravisantoshgudimetla

/lgtm

zparnold · 2018-09-12T03:45:45Z

@bsalamat I updated this PR with some style/grammar points. Let me know if it still means what you meant for it to. Otherwise it's ready to merge.
/approve

k8s-ci-robot · 2018-09-12T03:45:50Z

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bsalamat · 2018-09-12T04:35:18Z

@zparnold Your changes look good to me. Thanks for the edit!

zparnold · 2018-09-12T04:46:31Z

/lgtm

* Update docs for fields allowed at root of CRD schema (#9973) * add plugin docs and examples (#10053) * docs update to promote TaintNodesByCondition to beta (#9626) * HPA Specificity Improvements (#8757) Updated the HPA docs to reference the `autoscaling/v2beta2` API version, and added documentation about the new fields. * adjust docs for pod ready++ (#10049) * Remove --cadvisor-port - has been deprecated since v1.10 (#10023) Change-Id: Id2a685473a243aef492a98ff450759f39e362557 * Add Documentation for Snapshot Feature (#9948) * Add documentation for snapshot feature * Update volume-snapshots.md * Add dry-run to api-concepts (#10033) * kubeadm-init: Update the offline support section (#10062) The update includes the following things (in mind with Kubernetes 1.12): - Remove the 1.8 image versions - Add the 1.10 image versions that were missing until now - Include a comment for the missing arch suffixes in 1.12 Signed-off-by: Rostislav M. Georgiev <[email protected]> * Say bye to `DynamicProvisioningScheduling` (#10157) The mentioned feature gate is now collapsed into `VolumeScheduling`. xref: kubernetes/kubernetes#67432 * Update ResourceQuota per PriorityClass state for 1.12 (#10229) * TokenRequest and TokenRequestProjection now beta (#10161) xref: kubernetes/kubernetes#67349 * Change feature state for kms provider to beta. (#10230) KMS Provider will be graduating to beta in v1.12, reflecting this change on the website. * coredns default (#10200) * Promote ShareProcessNamespace to beta in docs (#9996) * Add CoreDNS details to DNS Debug docs (#10201) * add coredns details * address nits, add query logging section * Update docs with topology aware dynamic provisioning (#9939) * Document topology aware volume binding feature * update for readability * Update storage-classes.md * comma splice * don't abbreviate * HPA Algorithm Information Improvements (#9780) * Update HPA docs with more algorithm details The HPA docs pointed to an out-of-date document for information on the algorithm details, which users were finding confusing. This sticks a section on the algorithm in the HPA docs instead, documenting both general behavior and corner cases. * Add glossary info, HPA docs on quantities People often ask about the quantity notation when working with the metrics APIs, so this adds a glossary entry on quantities (since they're used elsewhere in the system), and a short explantation in the HPA walkthough. * Information about HPA readiness and stabilization This adds information about the new changes to HPA readiness and stabilization from kubernetes/enhancements#591, and other minor changes that landed in Kubernetes 1.12. * Update horizontal-pod-autoscale.md * Audit 1.12 doc (#9953) * audit 1.12 document * remove legacy audit feature kubernetes/kubernetes#65862 * update feature gate doc * MountPropagation is now GA (#10090) * RuntimeClass documentation (#10102) * RuntimeClass documentation * Update runtime-class.md * Add documentation for Scheduler performance tuning (#10048) * Add documentation for Scheduler performance tuning * Update scheduler-perf-tuning.md * TTL controller for cleaning up finished resources (#10064) * TTL controller for cleaning up finished resources * Address comments * Update ttlafterfinished.md * Bump quota configuration api version (#10217) * Incremental update from master (#10278) * fix invalid href of cloud controller manager (#10240) * fix invalid yaml format (#10238) * update storage-limits doc with Azure disk part (#10224) update storage-limits doc with Azure disk part fix comments * Update kubelet-config-file.md (#10222) Update link to KubeletConfiguration struct. * fix a trivial misspelling (#10244) * Fix cassandra-statefulset.yaml indent level (#10243) * Mention minimum etcd versions (#10208) Source: https://groups.google.com/d/msg/kubernetes-dev/jMPA4JzKiY4/HIx2ugvLBAAJ * fix 404 error (#10250) * Small verb tweak (#10190) Present participle, ftw. * Add AnchorJS logic for header links (#10155) * Add AnchorJS JavaScript * Remove existing inpage_heading logic * Remove underline from anchor tags * Use single icon and add touch visibility * Use paragraph link icon for AnchorJS * Update Sass to use code formatting in docsContent headers * Update header size coverage to H3-H6 * fix broken link in kubefed.md (#10254) * Update the version numbers for the X-Remote-Extra- and Impersonate-Extra- key fixes (#9827) The fix was cherry picked into 1.11.3, 1.10.7, and 1.9.11: kubernetes/kubernetes#67162 kubernetes/kubernetes#67163 kubernetes/kubernetes#67164 * fix typo (#10168) * fix typo * addressing comments. * Update setup-ha-etcd-with-kubeadm.md * fix typos (#10252) * fix description of contribute guide (#10253) * describe truncate feature about advanced audit (#10236) * describe truncate feature about advanced audit * Update audit.md * docs update to promote ScheduleDaemonSetPods to beta (#9923) * Dynamic volume limit updates for 1.12 (#10211) * add a placeholder commit * Update docs for csi volume limits * Update storage-limits.md * Add "MayRunAs" value among other GroupStrategies (#9888) * Add CoreDNS details to the customize DNS doc (#10228) * Add CoreDNS details to the customize DNS doc Rewrite the document to include more details about CoreDNS, since it's now the default from v1.12 * Address comments * Improve doc wording * Fix link * Update dns-custom-nameservers.md * Update dns-custom-nameservers.md * Fix secrets docs in 1.12 branch (#10056) * Fix secrets docs * Update secret.md * Revert CoreDNS Docs (#10319) * Revert "Add CoreDNS details to DNS Debug docs (#10201)" This reverts commit 462817a. * Revert "Add CoreDNS details to the customize DNS doc (#10228)" This reverts commit e7319ee. * Revert "coredns default (#10200)" This reverts commit 698e93b. * Add CRI installation instructions page Added cri-installation page with CRI installation instructions Referenced it from kubeadm-init and install-kubeadm pages. * kubeadm: update API types documentation for 1.12 (#10283) v1alpha2 -> v1alpha3 MasterConfiguration -> [new-api-types] * TokenRequest feature documentation (#10295) * AdvancedAuditing is now GA (#10156) xref: kubernetes/kubernetes#65862 `AdvancedAuditing` feature is GA in 1.12. This PR adjusts the related docs. * update runtime-class.md (#10332) * update runtime-class.md * Update runtime-class.md * Document cross-authorizer permissions for creating RBAC roles (#10015) * Document cross-authorizer permissions for creating RBAC roles * Update rbac.md * kubeadm: update authored content for 1.12 (reference docs and cluster creation) (#10348) * kubeadm: update authored content in reference docs for 1.12 * kubeadm: add time frame in create-cluster-kubeadm for 1.12 * add AllowedProcMountTypes and ProcMountType to docs (#9911) Signed-off-by: Jess Frazelle <[email protected]> * kubeadm: add new command line reference (#10306) Add: - placeholder files - include place holder files - include "renew" sub command - add missing tabs for "alpha phase kubelet" * Documenting SCTP support in Kubernetes (#10279) * Documenting SCTP support in Kubernetes Service, Endpoint, NetworkPolicy and Pod * Updates based on comments on the PR * kubectl expose update with SCTP support * Updated according to comments in the PR * Revert "kubectl expose update with SCTP support" This reverts commit 0d5a1e6. * TLS Bootstrap and Server Cert Rotation feature documentation (#10232) * TokenRequest feature documentation * line wrapping to make review not insane * update content for GA without major refactor * Update kubelet-tls-bootstrapping.md * Add clarifications for volume snapshots (#10296) * Update kubadm ha installation for 1.12 (#10264) * Update kubadm ha installation for 1.12 Signed-off-by: Chuck Ha <[email protected]> * update stable version Signed-off-by: Chuck Ha <[email protected]> * Update stacked control plane for v1.12 (#2) * use v1alpha3 Signed-off-by: Chuck Ha <[email protected]> * more v1alpha3 (#4) * updates Signed-off-by: Chuck Ha <[email protected]> * Document how to run in-tree cloud providers with kubeadm (#10357) Change-Id: Iab6b996a830503d74a6eb0c507c5f8ca7a39235b * kubeadm reference doc for release 1.12 (#10359) * Revert "Revert "Add CoreDNS details to DNS Debug docs (#10201)"" This reverts commit bb30f4d. * Revert "Revert "Add CoreDNS details to the customize DNS doc (#10228)"" This reverts commit bc23d45. * Revert "Revert "coredns default (#10200)"" This reverts commit 7f4350d. * add missing instruction for ha guide (#10374) Signed-off-by: Chuck Ha <[email protected]> * kubeadm - Ha upgrade updates (#10340) * Update HA upgrade docs * Adds external etcd HA upgrade guide Signed-off-by: Chuck Ha <[email protected]> * copyedit * more edits * add runasgroup in psp (#10076) * update KubeletPluginsWatcher feature gate (#10205) * generated 1.12 docs * Building Multi-arch images with Manifests (#10379) In 1.12, a variety of images used in a typical kubernetes installation have started to using manifests to better support environments with arm or ppc64le architectures. For example all images used with kubeadm by default have manifests, another would be all the tests in the conformance test suite. Here we capture the best practices for everyone to start using manifests in their own workflows. Change-Id: I5ba4c5fe55ffc9486a8251760f3352be4f2e1494 * Upgrade docs for v1.12 (#10344) * generated assets and docs * remove 1.7 * update 1.12 * update plugin documentation under docs>tasks>extend-kubectl (#10259) * update plugin documentation under docs>tasks>extend-kubectl * Update kubectl-plugins.md

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Scheduler checks feasibility and scores a subset of all cluster nodes kubernetes/enhancements#593

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Add documentation for Scheduler performance tuning

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Update scheduler-perf-tuning.md

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Add documentation for Scheduler performance tuning #10048

Add documentation for Scheduler performance tuning #10048

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		{{< feature-state for_k8s_version="1.12" >}}

		Kube-scheduler is the Kubernetes default scheduler. It is responsible for

		{{% capture overview %}}

		{{< feature-state for_k8s_version="1.12" >}}

Add documentation for Scheduler performance tuning #10048

Add documentation for Scheduler performance tuning #10048

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