Error: "VMkernel Live Patch is incompatible because the host has insufficient free memory" during ESX 9.0 live patching

Products

• VMware vSphere ESXi

Issue/Introduction

With the release of ESX 9.0, the operating system supports updating kernel code, including the VMkernel as well as kernel modules, without rebooting the host. Such updates are delivered via Live Patch images; vLCM can apply such an image on hosts running an ESX base image that is compatible with the specific Live Patch image. See the Live Patch product documentation for more details.

When a Live Patch affects kernel code, vLCM performs certain prechecks on each host. During the compliance scan, the following error may be reported:

VMkernel Live Patch is incompatible because the host has insufficient free memory (current memory state: <...>)

Environment

ESX 9.x

Cause

• The host does not have enough memory available to safely perform the kernel patching operation without risking the stability of the host and/or workloads.
• The host must be in a "HIGH" or "CLEAR" memory state to proceed.
• The amount of free memory to achieve these states varies based on the host's configuration.

Resolution

Reduce the memory load on the host by migrating, suspending, or powering-off workloads.

Additional Information

Live Patch product documentation: https://techdocs.broadcom.com/us/en/vmware-cis/vsphere/vsphere/9-0/managing-host-and-cluster-lifecycle/configuring-vlcm-remediation-settings-1/how-to-apply-live-patches-to-the-hosts-in-a-cluster-managed-with-images.html