mirror of
https://github.com/openshift/openshift-docs.git
synced 2026-02-06 06:46:26 +01:00
44 lines
1.8 KiB
Plaintext
44 lines
1.8 KiB
Plaintext
// Module included in the following assemblies:
|
|
//
|
|
// * nodes/nodes-cluster-overcommit.adoc
|
|
|
|
[id='nodes-cluster-overcommit-node-memory_{context}']
|
|
|
|
= Reserving memory across quality of service tiers
|
|
|
|
You can use the `qos-reserved` parameter to specify a percentage of memory to be reserved
|
|
by a pod in a particular QoS level. This feature attempts to reserve requested resources to exclude pods
|
|
from lower OoS classes from using resources requested by pods in higher QoS classes.
|
|
|
|
By reserving resources for higher QOS levels, pods that don't have resource limits are prevented from encroaching on the resources
|
|
requested by pods at higher QoS levels.
|
|
|
|
.Procedure
|
|
|
|
To configure the `qos-reserved` parameter, edit the appropriate node configuration map.
|
|
|
|
----
|
|
kubeletArguments:
|
|
cgroups-per-qos:
|
|
- true
|
|
cgroup-driver:
|
|
- 'systemd'
|
|
cgroup-root:
|
|
- '/'
|
|
qos-reserved: <1>
|
|
- 'memory=50%'
|
|
----
|
|
<1> Specifies how pod resource requests are reserved at the QoS level.
|
|
{product-title} uses the `qos-reserved` parameter as follows:
|
|
- A value of `qos-reserved=memory=100%` will prevent the `Burstable` and `BestEffort` QOS classes from consuming memory
|
|
that was requested by a higher QoS class. This increases the risk of inducing OOM
|
|
on `BestEffort` and `Burstable` workloads in favor of increasing memory resource guarantees
|
|
for `Guaranteed` and `Burstable` workloads.
|
|
- A value of `qos-reserved=memory=50%` will allow the `Burstable` and `BestEffort` QOS classes
|
|
to consume half of the memory requested by a higher QoS class.
|
|
- A value of `qos-reserved=memory=0%`
|
|
will allow a `Burstable` and `BestEffort` QoS classes to consume up to the full node
|
|
allocatable amount if available, but increases the risk that a `Guaranteed` workload
|
|
will not have access to requested memory. This condition effectively disables this feature.
|
|
|