whentimeslows/website
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Add Scheduling Configuration reference doc

Browse Source 
Built from the existing Scheduling Profiles doc.

Signed-off-by: Aldo Culquicondor <acondor@google.com>
This commit is contained in:
Aldo Culquicondor
2020-06-02 16:22:46 -04:00
parent 7825b79270
commit 72090c98af
7 changed files with 100 additions and 37 deletions
Download Patch File Download Diff File Expand all files Collapse all files
content/en/docs/reference/scheduling/profiles.md → content/en/docs/reference/scheduling/config.md
+91 -29
View File
@@ -1,30 +1,57 @@
---
title: Scheduling Profiles
title: Scheduler Configuration
content_type: concept
weight: 20
---
{{< feature-state for_k8s_version="v1.19" state="beta" >}}
The `KubeSchedulerConfiguration` is a configuration API for `kube-scheduler`
that can be provided as a file via `--config` command line flag.
<!-- overview -->
{{< feature-state for_k8s_version="v1.18" state="alpha" >}}
A scheduling Profile allows you to configure the different stages of scheduling
in the {{< glossary_tooltip text="kube-scheduler" term_id="kube-scheduler" >}}.
Each stage is exposed in a extension point. Plugins provide scheduling behaviors
by implementing one or more of these extension points.
You can specify scheduling profiles by running `kube-scheduler --config <filename>`,
using the component config APIs
([`v1alpha1`](https://pkg.go.dev/k8s.io/kube-scheduler@{{< param "fullversion" >}}/config/v1alpha1?tab=doc#KubeSchedulerConfiguration)
or [`v1alpha2`](https://pkg.go.dev/k8s.io/kube-scheduler@{{< param "fullversion" >}}/config/v1alpha2?tab=doc#KubeSchedulerConfiguration)).
The `v1alpha2` API allows you to configure kube-scheduler to run
[multiple profiles](#multiple-profiles).
<!-- body -->
## Extension points
## Minimal Configuration
A minimal configuration looks as follows:
```yaml
apiVersion: kubescheduler.config.k8s.io/v1beta1
kind: KubeSchedulerConfiguration
clientConnection:
kubeconfig: /etc/srv/kubernetes/kube-scheduler/kubeconfig
```
## Upgrading from `v1alpha2` to `v1beta1` {#beta-changes}
When migrating from `kubescheduler.config.k8s.io/v1alpha2` to `kubescheduler.config.k8s.io/v1beta1`,
beware of the following changes, if applicable:
- `.bindTimeoutSeconds` was moved as part of plugin args for `VolumeBinding`,
which can be configured separately per [profile](#profiles).
- `.extenders` are updated to satisfy API standards. In particular:
- `.extenders` decoding is case sensitive. All fields are affected.
- `.extenders[*].httpTimeout` is of type `metav1.Duration`.
- `.extenders[*].enableHttps` is renamed to `.extenders[*].enableHTTPS`.
- `RequestedToCapacityRatio` args decoding is case sensitive. All fields are affected.
- `DefaultPodTopologySpread` [plugin](#scheduling-plugins) is renamed to `SelectorSpread`.
- `Unreserve` extension point is removed from Profile definition. All `Reserve`
plugins implement an `Unreserve` call.
## Profiles
A scheduling Profile allows you to configure the different stages of scheduling
in the {{< glossary_tooltip text="kube-scheduler" term_id="kube-scheduler" >}}.
Each stage is exposed in a [extension point](#extension-points).
[Plugins](#scheduling-plugins) provide scheduling behaviors by implementing one
or more of these extension points.
A single instance of `kube-scheduler` can be configured to run
[multiple profiles](#multiple-profiles)
### Extension points
Scheduling happens in a series of stages that are exposed through the following
extension points:
@@ -43,7 +70,9 @@ extension points:
filtering phase. The scheduler will then select the node with the highest
weighted scores sum.
1. `Reserve`: This is an informational extension point that notifies plugins
when resources have being reserved for a given Pod.
when resources have been reserved for a given Pod. Plugins also implement an
`Unreserve` call that gets called in the case of failure during or after
`Reserve`.
1. `Permit`: These plugins can prevent or delay the binding of a Pod.
1. `PreBind`: These plugins perform any work required before a Pod is bound.
1. `Bind`: The plugins bind a Pod to a Node. Bind plugins are called in order
@@ -51,15 +80,35 @@ extension points:
least one bind plugin is required.
1. `PostBind`: This is an informational extension point that is called after
a Pod has been bound.
1. `UnReserve`: This is an informational extension point that is called if
a Pod is rejected after being reserved and put on hold by a `Permit` plugin.
For each extension point, you could disable specific [default plugins](#scheduling-plugins)
or enable your own. For example:
```yaml
apiVersion: kubescheduler.config.k8s.io/v1beta1
kind: KubeSchedulerConfiguration
profiles:
- plugins:
score:
disabled:
- name: NodeResourcesLeastAllocated
enabled:
- name: MyCustomPluginA
weight: 2
- name: MyCustomPluginB
weight: 1
```
You can use `*` as name in the disabled array to disable all default plugins
for that extension point. This can also be used to rearrange plugins order, if
desired.
## Scheduling plugins
### Scheduling plugins
The following plugins, enabled by default, implement one or more of these
extension points:
- `DefaultTopologySpread`: Favors spreading across nodes for Pods that belong to
- `SelectorSpread`: Favors spreading across nodes for Pods that belong to
{{< glossary_tooltip text="Services" term_id="service" >}},
{{< glossary_tooltip text="ReplicaSets" term_id="replica-set" >}} and
{{< glossary_tooltip text="StatefulSets" term_id="statefulset" >}}
@@ -99,7 +148,7 @@ extension points:
Extension points: `Score`.
- `VolumeBinding`: Checks if the node has or if it can bind the requested
{{< glossary_tooltip text="volumes" term_id="volume" >}}.
Extension points: `Filter`.
Extension points: `PreFilter`, `Filter`, `Reserve`, `PreBind`.
- `VolumeRestrictions`: Checks that volumes mounted in the node satisfy
restrictions that are specific to the volume provider.
Extension points: `Filter`.
@@ -147,10 +196,25 @@ that are not enabled by default:
Service across nodes.
Extension points: `PreFilter`, `Filter`, `Score`.
## Multiple profiles
### Multiple profiles
`kube-scheduler` can be configured to
run more than one profile. Each profile has an associated scheduler name. Each
profile can have a different set of plugins configured in its
[extension points](#extension-points).
```yaml
apiVersion: kubescheduler.config.k8s.io/v1beta1
kind: KubeSchedulerConfiguration
profiles:
- schedulerName: default-scheduler
- schedulerName: no-scoring-scheduler
plugins:
score:
disabled:
- name: '*'
```
When using the component config API v1alpha2, a scheduler can be configured to
run more than one profile. Each profile has an associated scheduler name.
Pods that want to be scheduled according to a specific profile can include
the corresponding scheduler name in its `.spec.schedulerName`.
@@ -174,8 +238,6 @@ the same configuration parameters (if applicable). This is because the scheduler
only has one pending pods queue.
{{< /note >}}
## {{% heading "whatsnext" %}}
* Learn about [scheduling](/docs/concepts/scheduling-eviction/kube-scheduler/)
content/en/docs/reference/scheduling/policies.md
+1 -1
View File
@@ -122,5 +122,5 @@ The following *priorities* implement scoring:
## {{% heading "whatsnext" %}}
* Learn about [scheduling](/docs/concepts/scheduling-eviction/kube-scheduler/)
* Learn about [kube-scheduler profiles](/docs/reference/scheduling/profiles/)
* Learn about [kube-scheduler Configuration](/docs/reference/scheduling/config/)