Sync CNV runbook HCOMisconfiguredDescheduler.md (Updated at 2024-09-19 09:04:21 +0000 UTC) #213
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@jherrman Hi, This PR needs a review please. |
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/lgtm |
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| ## Meaning | ||
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| A Descheduler is a OpenShift Container Platform application that causes the |
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-> an OpenShift...
Also probably lower-case case d and italics for descheduler
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| The descheduler uses the OpenShift Container Platform eviction API to evict | ||
| pods, and receives | ||
| feedback from `kube-api` whether the eviction request was granted or not. |
| On the other side, in order to keep VM live and trigger live-migration, | ||
| OpenShift Virtualization handles eviction requests in a custom way and | ||
| unfortunately | ||
| a live migration takes time. |
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-> In contrast, to keep a VM live and trigger a live migration, OpenShift Virtualization handles eviction requests in a custom manner, and a live migration takes time to perform.
| So from the descheduler's point of view, `virt-launcher` pods fail to be | ||
| evicted, but they actually migrating to another node in background. | ||
| So the way OpenShift Virtualization handles eviction requests causes the | ||
| descheduler to | ||
| make wrong decisions and take wrong actions that could destabilize the cluster. |
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-> Therefore, when a virt-launcher pod is migrating to another node in the background, the descheduler detects this as a pod that failed to be evicted. As a consequence, the manner in which OpenShift Virtualization handles eviction requests causes the descheduler to make incorrect decisions and take incorrect actions that might destabilize the cluster.
| descheduler to | ||
| make wrong decisions and take wrong actions that could destabilize the cluster. | ||
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| To correctly handle the special case of `VM` pod evicted triggering a live |
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-> ... the special case of an evicted VM pod triggering...
| $ oc get -n openshift-kube-descheduler-operator KubeDescheduler cluster -o yaml | ||
| ``` | ||
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| looking for: |
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-> 2. Search for the following lines in the CR:
| If not there, the `Kube Descheduler Operator` is not correctly configured | ||
| to work alongside OpenShift Virtualization. |
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-> If these lines are not present, the...
| Set: | ||
| ```yaml | ||
| spec: | ||
| profileCustomizations: | ||
| devEnableEvictionsInBackground: true | ||
| ``` | ||
| on the CR for the `Kube Descheduler Operator` or | ||
| remove the `Kube Descheduler Operator`. |
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-> Do one of the following:
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Add the following lines to the CR for
Kube Descheduler Operator:spec: profileCustomizations: devEnableEvictionsInBackground: true
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Remove the
Kube Descheduler Operator
| on the CR for the `Kube Descheduler Operator` or | ||
| remove the `Kube Descheduler Operator`. | ||
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| Please notice that `EvictionsInBackground` is an alpha feature, |
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-> Note that devEnableEvictionsInBackground...
| and it's subject to change and currently provided as an | ||
| experimental feature. |
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-> and as such, it is provided as an experimental feature and is subject to change.
Based on openshift/runbooks#213 Signed-off-by: Jiri Herrmann <jherrman@redhat.com>
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Created an upstream PR for the changes, as Shirly suggested: kubevirt/monitoring#273 |
This is an automated PR by 'tools/openshift-virtualization-operator/runbook-sync'.
CNV runbook 'HCOMisconfiguredDescheduler.md' was updated in upstream https://github.com/kubevirt/monitoring at 2024-09-19 09:04:21 +0000 UTC.
This PR syncs the runbook in this repository to contain all new added changes.
/cc @machadovilaca