Parallel Remediation (VLCM) performs upgrades sequentially on ESXi hosts

Products

• VMware vCenter Server

Issue/Introduction

Parallel remediation is set within vSphere Lifecycle Manager, but the upgrades of ESXi hosts still happen sequentially, one at a time.

Unable to upgrade more that one ESXi host at a time with NSX-enabled clusters (although this has no connection with NSX).

We see that when applying the firmware upgrade, hosts are remediated one at a time (see screenshot below):

 

How to Configure the vSphere Lifecycle Manager Remediation Settings
https://techdocs.broadcom.com/us/en/vmware-cis/vsphere/vsphere/8-0/managing-host-and-cluster-lifecycle-8-0/configuring-vlcm-remediation-settings-1/configure-the-vlcm-remediation-settings.html

Environment

vCenter 7.x

vCenter 8.x

Cause

This is expected behaviour and is something documented by respective HSM plugin providers like HPE, Cisco and Dell OpenManage.

Essentially, when there is firmware included in a custom ESXi host image from any hardware vendors, the upgrade will only work sequentially and this is by design. 

Firmware lifecycle made simple with vSphere Lifecycle Manager and HSM providers
https://blogs.vmware.com/cloud-foundation/2024/11/07/firmware-lifecycle-made-simple-with-vsphere-lifecycle-manager

 

Resolution

Plan downtime accordingly since only sequential upgrades are possible with firmware upgrades through vCenter.