Current deployment procedure lacks the support of upgrade scenario to OCP 4.21 where KubeletConfig is not allowed to configure the failOnSwap flag.

In order to overcome this issue the procedure should be updated with the correct MachineConfig object. The addition to the MachineConfig includes generation of the kubelet drop-in in /etc/openshift/kubelet.conf.d

With this file being generated in CNV 4.20 swap will continue to work after upgrading to OCP 4.21

4.20.x

100%

1. Deploy CNV 4.20 on OCP 4.20
2. Apply VM higher density deployment procedure according to the 4.20 docs
3. Perform OCP upgrade to 4.21

After upgrade the KubeletConfig will be blocked and the failSwapOn flag won't be propagated to kubelet

Using the drop-in configuration file the failOnSwap flag will be propagated to kubelet so there won't be any dependency on the rejected KubeletConfig object

In the 4.21 docs we will need to add that on when upgrading from 4.20 the user needs to delete the KubeletConfig object since its not needed anymore because of the usage of the drop-in file in MachineConfig