Ensure KSM is disabled

LowLevel 2Automatedopenshift-virt

Description

Kernel Samepage Merging (KSM) is a Linux kernel feature that merges identical memory pages across virtual machines running on a single host, potentially reducing memory usage and improving system performance. Audit: Passes when .spec.ksmConfiguration of the HyperConverged resource is unset or false (KSM is disabled by default); any KSM node selector configuration fails. Requires oc logged in to the cluster with read access.

How it is checked

Audit method: Shell command

shell

command -v oc >/dev/null 2>&1 || exit 1; v=$(oc get hyperconvergeds kubevirt-hyperconverged -n openshift-cnv -o jsonpath='{.spec.ksmConfiguration}') || exit 1; case "$v" in ""|false|null|"{}") echo compliant;; *) echo noncompliant;; esac

Expected output: compliant

How it is fixed

Fix method: Guidance or infrastructure patch

Disable the KSM feature.For example, by directly editing the object with oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv and set the field to false

Properties

Operating systems: Any
Tags: openshift-virtmemoryksm
Reference: CIS Red Hat OpenShift Virtual Machine Extension Benchmark v1.0.0 - 1.7 Ensure KSM is disabled

Check this host

Run this on a machine you are allowed to audit. The scan is read-only.

shell

tmaegis scan --target openshift-virt --level 2