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docs/doc/source/admintasks/kubernetes/kubernetes-cpu-manager-policies.rst
Ron Stone f125a8b892 Remove spurious escapes (r8,dsR8) 
This change addresses a long-standing issue in rST documentation imported from XML.
That import process added backslash escapes in front of various characters. The three
most common being '(', ')', and '_'.
These instances are removed.

Signed-off-by: Ron Stone <ronald.stone@windriver.com>
Change-Id: Id43a9337ffcd505ccbdf072d7b29afdb5d2c997e
2023-03-01 11:19:04 +00:00

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Kubernetes CPU Manager Policies

You can apply the kube-cpu-mgr-policy host label from the Horizon Web interface or the CLI to set the Kubernetes CPU Manager policy.

The kube-cpu-mgr-policy host label supports the values none and static.

For example:

~(keystone)admin)$ system host-lock worker-1
~(keystone)admin)$ system host-label-assign --overwrite worker-1 kube-cpu-mgr-policy=static
~(keystone)admin)$ system host-unlock worker-1

Setting either of these values results in kubelet on the host being configured with the policy of the same name as described at https://kubernetes.io/docs/tasks/administer-cluster/cpu-management-policies/#cpu-management-policies, but with the following differences:

Static policy customizations

  • Pods in the kube-system namespace are affined to platform cores only. Other pod containers (hosted applications) are restricted to running on either the application or isolated cores. CFS quota throttling for Guaranteed QoS pods is disabled.
  • When using the static policy, improved performance can be achieved if you also use the Isolated CPU behavior as described at Isolating CPU Cores to Enhance Application Performance <isolating-cpu-cores-to-enhance-application-performance>.
  • For Kubernetes pods with a Guaranteed QoS (see https://kubernetes.io/docs/tasks/configure-pod-container/quality-service-pod/ for background information), CFS quota throttling is disabled as it causes performance degradation.
  • Kubernetes pods are prevented by default from running on CPUs with an assigned function of Platform. In contrast, pods in the kube-system namespace are affined to run on Platform CPUs by default. This assumes that the number of platform CPUs is sufficiently large to handle the workload. These two changes further ensure that low-latency applications are not interrupted by housekeeping tasks.

Recommendations

recommends using the static policy.

See also

See : Use Kubernetes CPU Manager Static Policy’s Guaranteed QoS class with exclusive CPUs <using-kubernetes-cpu-manager-static-policy> for an example of how to configure a Pod in the ‘Guaranteed QOS’ class with exclusive (or dedicated/pinned) cpus.

See : Use Kubernetes CPU Manager Static Policy with application-isolated cores <use-application-isolated-cores> for an example of how to configure a Pod with cores that are both ‘isolated from the host process scheduler’ and exclusive/dedicated/pinned cpus.