Merge pull request #40890 from windsonsea/enventp
Fix tab tags and indentations in switch-to-evented-pleg.mdpull/40642/head^2
Kubernetes Prow Robot
GitHub
commit
cd4cad9599
|
|
@ -1,5 +1,5 @@
|
|||
---
|
||||
title: Switching From Polling to CRI Event-based Updates to Container Status
|
||||
title: Switching from Polling to CRI Event-based Updates to Container Status
|
||||
min-kubernetes-server-version: 1.26
|
||||
content_type: task
|
||||
weight: 90
|
||||
|
|
@ -8,84 +8,91 @@ weight: 90
|
|||
{{< feature-state for_k8s_version="v1.26" state="beta" >}}
|
||||
|
||||
<!-- overview -->
|
||||
|
||||
This page shows how to migrate notes to use event based updates for container status. The event-based
|
||||
implementation reduces node resource consumption by the kubelet, compared to the legacy approach
|
||||
that relies on polling.
|
||||
You may know this feature as _evented Pod lifecycle event generator (PLEG)_. That's the name used
|
||||
internally within the Kubernetes project for a key implementation detail.
|
||||
|
||||
|
||||
## {{% heading "prerequisites" %}}
|
||||
|
||||
* You need to run a version of Kubernetes that provides this feature.
|
||||
Kubernetes {{< skew currentVersion >}} includes beta support for event-based container
|
||||
status updates. The feature is beta and is disabled by default.
|
||||
{{< version-check >}}
|
||||
If you are running a different version of Kubernetes, check the documentation for that release.
|
||||
|
||||
Kubernetes {{< skew currentVersion >}} includes beta support for event-based container
|
||||
status updates. The feature is beta and is disabled by default.
|
||||
{{< version-check >}}
|
||||
If you are running a different version of Kubernetes, check the documentation for that release.
|
||||
|
||||
<!-- steps -->
|
||||
|
||||
## Why switch to Evented PLEG?
|
||||
|
||||
* The current `Generic PLEG` incurs non-negligible overhead due to frequent polling of container statuses.
|
||||
* This overhead is exacerbated by Kubelet's parallelism, limiting its scalability and causing poor performance and reliability problems.
|
||||
* This overhead is exacerbated by Kubelet's parallelism, limiting its scalability
|
||||
and causing poor performance and reliability problems.
|
||||
* The goal of `Evented PLEG` is to reduce unnecessary work during inactivity by replacing periodic polling.
|
||||
|
||||
## Switching to Evented PLEG
|
||||
|
||||
1. Start the Kubelet with the [feature gate](/docs/reference/command-line-tools-reference/feature-gates/)
|
||||
`EventedPLEG` enabled. In Kubelet feature gates can be enabled by editing
|
||||
[config file](/docs/tasks/administer-cluster/kubelet-config-file/) and restarting the Kubelet service.
|
||||
|
||||
1. Start the Kubelet with the [feature gate](https://kubernetes.io/docs/reference/command-line-tools-reference/feature-gates/) `EventedPLEG` enabled. In Kubelet feature gates can be enabled by editing [config file](https://kubernetes.io/docs/tasks/administer-cluster/kubelet-config-file/) and restarting the Kubelet service.
|
||||
2. Please make sure the node is [drained](/docs/tasks/administer-cluster/safely-drain-node/) before proceeding.
|
||||
|
||||
2. Please make sure the node is [drained](https://kubernetes.io/docs/tasks/administer-cluster/safely-drain-node/) before proceeding.
|
||||
3. Start the `CRI Runtime` with the `Evented PLEG` support.
|
||||
|
||||
3. Start the `CRI Runtime` with the `Evented PLEG` support.
|
||||
{{< tabs name="tab_with_code" >}}
|
||||
{{< tab name="Containerd" codelang="bash" >}}
|
||||
Version 1.7+
|
||||
{{< /tab >}}
|
||||
{{< tab name="CRI-O" codelang="bash" >}}
|
||||
Version 1.26+
|
||||
|
||||
Check if the CRI-O is already configured to emit `CRI Events` by verifying the configuration,
|
||||
```
|
||||
$ crio config | grep enable_pod_events
|
||||
```
|
||||
If its enabled it should show,
|
||||
```
|
||||
# enable_pod_events = true
|
||||
```
|
||||
{{< tabs name="tab_with_code" >}}
|
||||
|
||||
To enable it, start the cri-o daemon with the flag `--enable-pod-events=true` or using a drop in config like,
|
||||
|
||||
[crio.runtime]
|
||||
enable_pod_events: true
|
||||
|
||||
{{% tab name="containerd" %}}
|
||||
Version 1.7+
|
||||
{{% /tab %}}
|
||||
|
||||
{{< /tab >}}
|
||||
{{< /tabs >}}
|
||||
{{% tab name="CRI-O" %}}
|
||||
Version 1.26+
|
||||
|
||||
Check if the CRI-O is already configured to emit `CRI Events` by verifying the configuration:
|
||||
|
||||
{{< version-check >}}
|
||||
```shell
|
||||
crio config | grep enable_pod_events
|
||||
```
|
||||
|
||||
4. Verify that `Evented PLEG` is in use by looking for the term `EventedPLEG` in the kubelet logs
|
||||
If it is enabled it should show:
|
||||
|
||||
The output is similar to this:
|
||||
```
|
||||
I0314 11:10:13.909915 1105457 feature_gate.go:249] feature gates: &{map[EventedPLEG:true]}
|
||||
```
|
||||
```
|
||||
enable_pod_events = true
|
||||
```
|
||||
|
||||
If you have set LOG_LEVEL to 4 and above, you might see more entries that indicate `Evented PLEG` is in use by the kubelet.
|
||||
|
||||
```
|
||||
I0314 11:12:42.009542 1110177 evented.go:238] "Evented PLEG: Generated pod status from the received event" podUID=3b2c6172-b112-447a-ba96-94e7022912dc
|
||||
I0314 11:12:44.623326 1110177 evented.go:238] "Evented PLEG: Generated pod status from the received event" podUID=b3fba5ea-a8c5-4b76-8f43-481e17e8ec40
|
||||
I0314 11:12:44.714564 1110177 evented.go:238] "Evented PLEG: Generated pod status from the received event" podUID=b3fba5ea-a8c5-4b76-8f43-481e17e8ec40
|
||||
```
|
||||
To enable it, start the cri-o daemon with the flag `--enable-pod-events=true` or using a drop in config like:
|
||||
|
||||
```
|
||||
[crio.runtime]
|
||||
enable_pod_events: true
|
||||
```
|
||||
|
||||
{{% /tab %}}
|
||||
{{< /tabs >}}
|
||||
|
||||
{{< version-check >}}
|
||||
|
||||
4. Verify that `Evented PLEG` is in use by looking for the term `EventedPLEG` in the kubelet logs.
|
||||
|
||||
The output is similar to this:
|
||||
|
||||
```
|
||||
I0314 11:10:13.909915 1105457 feature_gate.go:249] feature gates: &{map[EventedPLEG:true]}
|
||||
```
|
||||
|
||||
If you have set LOG_LEVEL to 4 and above, you might see more entries that
|
||||
indicate `Evented PLEG` is in use by the kubelet.
|
||||
|
||||
```
|
||||
I0314 11:12:42.009542 1110177 evented.go:238] "Evented PLEG: Generated pod status from the received event" podUID=3b2c6172-b112-447a-ba96-94e7022912dc
|
||||
I0314 11:12:44.623326 1110177 evented.go:238] "Evented PLEG: Generated pod status from the received event" podUID=b3fba5ea-a8c5-4b76-8f43-481e17e8ec40
|
||||
I0314 11:12:44.714564 1110177 evented.go:238] "Evented PLEG: Generated pod status from the received event" podUID=b3fba5ea-a8c5-4b76-8f43-481e17e8ec40
|
||||
```
|
||||
|
||||
## {{% heading "whatsnext" %}}
|
||||
|
||||
* Learn more about [KEP 3386](https://github.com/kubernetes/enhancements/blob/5b258a990adabc2ffdc9d84581ea6ed696f7ce6c/keps/sig-node/3386-kubelet-evented-pleg/README.md).
|
||||
|
||||
|
||||
|
||||
* Learn more about
|
||||
[KEP 3386](https://github.com/kubernetes/enhancements/blob/5b258a990adabc2ffdc9d84581ea6ed696f7ce6c/keps/sig-node/3386-kubelet-evented-pleg/README.md).
|
||||
|
|
|
|||
Loading…
Reference in New Issue