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mirror of https://github.com/kubernetes-sigs/descheduler.git synced 2026-01-28 06:29:29 +01:00

Addressing review comments

Both LowNode and HighNode utilization strategies evict only as many pods
as there's free resources on other nodes. Thus, the resource fit test
is always true by definition.
This commit is contained in:
Jan Chaloupka
2022-04-28 12:00:28 +02:00
parent 16eb9063b6
commit 3eca2782d4
7 changed files with 70 additions and 176 deletions

View File

@@ -226,10 +226,10 @@ If that parameter is set to `true`, the thresholds are considered as percentage
`thresholds` will be deducted from the mean among all nodes and `targetThresholds` will be added to the mean.
A resource consumption above (resp. below) this window is considered as overutilization (resp. underutilization).
**NOTE:** Node resource consumption is determined by the requests and limits of pods, not actual usage.
This approach is chosen in order to maintain consistency with the kube-scheduler, which follows the same
design for scheduling pods onto nodes. This means that resource usage as reported by Kubelet (or commands
like `kubectl top`) may differ from the calculated consumption, due to these components reporting
**NOTE:** Node resource consumption is determined by the requests and limits of pods, not actual usage.
This approach is chosen in order to maintain consistency with the kube-scheduler, which follows the same
design for scheduling pods onto nodes. This means that resource usage as reported by Kubelet (or commands
like `kubectl top`) may differ from the calculated consumption, due to these components reporting
actual usage metrics. Implementing metrics-based descheduling is currently TODO for the project.
**Parameters:**
@@ -280,8 +280,8 @@ under utilized frequently or for a short period of time. By default, `numberOfNo
### HighNodeUtilization
This strategy finds nodes that are under utilized and evicts pods from the nodes in the hope that these pods will be
scheduled compactly into fewer nodes. Used in conjunction with node auto-scaling, this strategy is intended to help
This strategy finds nodes that are under utilized and evicts pods from the nodes in the hope that these pods will be
scheduled compactly into fewer nodes. Used in conjunction with node auto-scaling, this strategy is intended to help
trigger down scaling of under utilized nodes.
This strategy **must** be used with the scheduler scoring strategy `MostAllocated`. The parameters of this strategy are
configured under `nodeResourceUtilizationThresholds`.
@@ -300,10 +300,10 @@ strategy evicts pods from `underutilized nodes` (those with usage below `thresho
so that they can be recreated in appropriately utilized nodes.
The strategy will abort if any number of `underutilized nodes` or `appropriately utilized nodes` is zero.
**NOTE:** Node resource consumption is determined by the requests and limits of pods, not actual usage.
This approach is chosen in order to maintain consistency with the kube-scheduler, which follows the same
design for scheduling pods onto nodes. This means that resource usage as reported by Kubelet (or commands
like `kubectl top`) may differ from the calculated consumption, due to these components reporting
**NOTE:** Node resource consumption is determined by the requests and limits of pods, not actual usage.
This approach is chosen in order to maintain consistency with the kube-scheduler, which follows the same
design for scheduling pods onto nodes. This means that resource usage as reported by Kubelet (or commands
like `kubectl top`) may differ from the calculated consumption, due to these components reporting
actual usage metrics. Implementing metrics-based descheduling is currently TODO for the project.
**Parameters:**
@@ -737,9 +737,9 @@ The following strategies accept a `nodeFit` boolean parameter which can optimize
If set to `true` the descheduler will consider whether or not the pods that meet eviction criteria will fit on other nodes before evicting them. If a pod cannot be rescheduled to another node, it will not be evicted. Currently the following criteria are considered when setting `nodeFit` to `true`:
- A `nodeSelector` on the pod
- Any `Tolerations` on the pod and any `Taints` on the other nodes
- Any `tolerations` on the pod and any `taints` on the other nodes
- `nodeAffinity` on the pod
- Resource `Requests` made by the pod and the resources available on other nodes
- Resource `requests` made by the pod and the resources available on other nodes
- Whether any of the other nodes are marked as `unschedulable`
E.g.