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28 lines
1.4 KiB
Plaintext
28 lines
1.4 KiB
Plaintext
// Module included in the following assemblies:
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//
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// * nodes/nodes-cluster-overcommit.adoc
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// * post_installation_configuration/node-tasks.adoc
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[id="nodes-cluster-overcommit-resource-requests_{context}"]
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= Resource requests and overcommitment
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For each compute resource, a container may specify a resource request and limit.
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Scheduling decisions are made based on the request to ensure that a node has
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enough capacity available to meet the requested value. If a container specifies
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limits, but omits requests, the requests are defaulted to the limits. A
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container is not able to exceed the specified limit on the node.
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The enforcement of limits is dependent upon the compute resource type. If a
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container makes no request or limit, the container is scheduled to a node with
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no resource guarantees. In practice, the container is able to consume as much of
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the specified resource as is available with the lowest local priority. In low
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resource situations, containers that specify no resource requests are given the
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lowest quality of service.
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Scheduling is based on resources requested, while quota and hard limits refer
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to resource limits, which can be set higher than requested resources. The
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difference between request and limit determines the level of overcommit;
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for instance, if a container is given a memory request of 1Gi and a memory limit
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of 2Gi, it is scheduled based on the 1Gi request being available on the node,
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but could use up to 2Gi; so it is 100% overcommitted.
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