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Revise Pod concept (#22603)

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* Revise Pod concept

Adapt the existing Pod documentation to suit the Docsy theme, by
promoting the Pod concept itself to /docs/concepts/workloads/pods/

Following on from this, update the Pod Lifecycle page to cover the
lifecycle of a Pod and follow on directly from the Pod concept,
for readers keen to understand things in detail.

This change also removes the automatic contents list from the Pod
overview page. Instead, the new page links to all the pages
inside the Pod section.

* Update links to Pod concept

Link to updated content

* Incorporate Pod concept suggestions

Co-authored-by: Celeste Horgan <celeste@cncf.io>

* Revise StatefulSet suggestion for Pod concept

Co-authored-by: Celeste Horgan <celeste@cncf.io>

Co-authored-by: Celeste Horgan <celeste@cncf.io>
This commit is contained in:
Tim Bannister
2020-07-27 04:18:16 +01:00
committed by GitHub
parent c80c9c40c1
commit 49eee8fd3d
31 changed files with 704 additions and 736 deletions
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content/en/docs/concepts/workloads/pods/podpreset.md
+24 -27
View File
@@ -1,7 +1,7 @@
---
reviewers:
- jessfraz
title: Pod Preset
title: Pod Presets
content_type: concept
weight: 50
---
@@ -32,20 +32,20 @@ specific service do not need to know all the details about that service.
In order to use Pod presets in your cluster you must ensure the following:
1. You have enabled the API type `settings.k8s.io/v1alpha1/podpreset`. For
example, this can be done by including `settings.k8s.io/v1alpha1=true` in
the `--runtime-config` option for the API server. In minikube add this flag
`--extra-config=apiserver.runtime-config=settings.k8s.io/v1alpha1=true` while
starting the cluster.
1. You have enabled the admission controller `PodPreset`. One way to doing this
is to include `PodPreset` in the `--enable-admission-plugins` option value specified
for the API server. In minikube, add this flag
```shell
--extra-config=apiserver.enable-admission-plugins=NamespaceLifecycle,LimitRanger,ServiceAccount,DefaultStorageClass,DefaultTolerationSeconds,NodeRestriction,MutatingAdmissionWebhook,ValidatingAdmissionWebhook,ResourceQuota,PodPreset
```
while starting the cluster.
1. You have enabled the API type `settings.k8s.io/v1alpha1/podpreset`. For
example, this can be done by including `settings.k8s.io/v1alpha1=true` in
the `--runtime-config` option for the API server. In minikube add this flag
`--extra-config=apiserver.runtime-config=settings.k8s.io/v1alpha1=true` while
starting the cluster.
1. You have enabled the admission controller named `PodPreset`. One way to doing this
is to include `PodPreset` in the `--enable-admission-plugins` option value specified
for the API server. For example, if you use Minikube, add this flag:
```shell
--extra-config=apiserver.enable-admission-plugins=NamespaceLifecycle,LimitRanger,ServiceAccount,DefaultStorageClass,DefaultTolerationSeconds,NodeRestriction,MutatingAdmissionWebhook,ValidatingAdmissionWebhook,ResourceQuota,PodPreset
```
while starting your cluster.
## How it works
@@ -64,31 +64,28 @@ When a pod creation request occurs, the system does the following:
modified by a `PodPreset`. The annotation is of the form
`podpreset.admission.kubernetes.io/podpreset-<pod-preset name>: "<resource version>"`.
Each Pod can be matched by zero or more Pod Presets; and each `PodPreset` can be
applied to zero or more pods. When a `PodPreset` is applied to one or more
Pods, Kubernetes modifies the Pod Spec. For changes to `Env`, `EnvFrom`, and
`VolumeMounts`, Kubernetes modifies the container spec for all containers in
the Pod; for changes to `Volume`, Kubernetes modifies the Pod Spec.
Each Pod can be matched by zero or more PodPresets; and each PodPreset can be
applied to zero or more Pods. When a PodPreset is applied to one or more
Pods, Kubernetes modifies the Pod Spec. For changes to `env`, `envFrom`, and
`volumeMounts`, Kubernetes modifies the container spec for all containers in
the Pod; for changes to `volumes`, Kubernetes modifies the Pod Spec.
{{< note >}}
A Pod Preset is capable of modifying the following fields in a Pod spec when appropriate:
- The `.spec.containers` field.
- The `initContainers` field (requires Kubernetes version 1.14.0 or later).
- The `.spec.containers` field
- The `.spec.initContainers` field
{{< /note >}}
### Disable Pod Preset for a Specific Pod
### Disable Pod Preset for a specific pod
There may be instances where you wish for a Pod to not be altered by any Pod
Preset mutations. In these cases, you can add an annotation in the Pod Spec
preset mutations. In these cases, you can add an annotation in the Pod's `.spec`
of the form: `podpreset.admission.kubernetes.io/exclude: "true"`.
## {{% heading "whatsnext" %}}
See [Injecting data into a Pod using PodPreset](/docs/tasks/inject-data-application/podpreset/)
For more information about the background, see the [design proposal for PodPreset](https://git.k8s.io/community/contributors/design-proposals/service-catalog/pod-preset.md).