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39 lines
2.1 KiB
Plaintext
39 lines
2.1 KiB
Plaintext
// Module included in the following assemblies:
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//
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// * scalability_and_performance/telco_core_ref_design_specs/telco-core-rds.adoc
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:_mod-docs-content-type: REFERENCE
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[id="telco-core-scheduling_{context}"]
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= Scheduling
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New in this release::
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* No reference design updates in this release.
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Description::
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The scheduler is a cluster-wide component responsible for selecting the right node for a given workload.
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It is a core part of the platform and does not require any specific configuration in the common deployment scenarios.
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However, there are few specific use cases described in the following section.
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+
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NUMA-aware scheduling can be enabled through the NUMA Resources Operator.
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For more information, see "Scheduling NUMA-aware workloads".
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Limits and requirements::
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* The default scheduler does not understand the NUMA locality of workloads.
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It only knows about the sum of all free resources on a worker node.
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This might cause workloads to be rejected when scheduled to a node with the topology manager policy set to single-numa-node or restricted.
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For more information, see "Topology Manager policies"..
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** For example, consider a pod requesting 6 CPUs and being scheduled to an empty node that has 4 CPUs per NUMA node.
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The total allocatable capacity of the node is 8 CPUs. The scheduler places the pod on the empty node.
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The node local admission fails, as there are only 4 CPUs available in each of the NUMA nodes.
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* All clusters with multi-NUMA nodes are required to use the NUMA Resources Operator.
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See "Installing the NUMA Resources Operator" for more information.
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Use the `machineConfigPoolSelector` field in the `KubeletConfig` CR to select all nodes where NUMA aligned scheduling is required.
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* All machine config pools must have consistent hardware configuration.
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For example, all nodes are expected to have the same NUMA zone count.
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Engineering considerations::
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* Pods might require annotations for correct scheduling and isolation.
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For more information about annotations, see "CPU partitioning and performance tuning".
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* You can configure SR-IOV virtual function NUMA affinity to be ignored during scheduling by using the excludeTopology field in `SriovNetworkNodePolicy` CR.
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