RHEL 9 upgrade fails with "Leapp detected a processor which is no longer maintained in RHEL 9" error

Products

• VMware vSphere ESXi

Issue/Introduction

• When performing an in-place upgrade to Red Hat Enterprise Linux (RHEL) 9.1 using the Leapp utility, the process fails with a high-risk error.
• A similar error to the following is reported in the Leapp pre-upgrade report:

Risk Factor: high
Title: Leapp detected a processor which is no longer maintained in RHEL 9.
Summary: The following processors are no longer maintained in RHEL 9:
      - NEHALEM_EP

Environment

VMware ESXi

RedHat Guest OS

Cause

• RHEL 9 requires the x86-64-v2 instruction set to function. The virtual machine, in the example above, is currently presented with a "Nehalem" CPU baseline via the cluster's EVC configuration, which does not provide the required CPU instructions for RHEL 9.

Resolution

• To resolve this issue, you must upgrade the EVC baseline for the cluster to a generation that supports the x86-64-v2 instruction set.

1. Navigate to your Cluster in vCenter.
2. Select the Configure tab and go to VMware EVC.
3. Click Edit and change the EVC mode to Intel "Cascade Lake" Generation. Note: In a mixed cluster, you must set the EVC mode to the highest baseline supported by all hosts in that cluster.
4. After you apply the changes, you must completely power off and then power on the affected virtual machines. Important: A guest OS restart is not sufficient; a cold boot is required for the VM to recognize the new CPU instruction sets.
5. Once the VM is powered back on, rerun the Leapp upgrade utility.

• Please note if you have an ESXi Cluster with mixed processor types, such as Intel Xeon Silver 4215R (Cascade Lake) and Intel Xeon Gold 5515+ (Sapphire Rapids). In a mixed cluster, you should set the EVC mode to the highest baseline supported by all hosts. In this example, this would be Intel Cascade Lake Generation. This can be confirmed by checking the Broadcom compatibility guide.

Additional Information

For more details on EVC and CPU version compatibility, please refer to the following resources:

• vCenter EVC and CPU compatibility (313545)